1680 lines
48 KiB
C
1680 lines
48 KiB
C
/* $NetBSD: kern_clock.c,v 1.71 2000/08/26 04:01:16 sommerfeld Exp $ */
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/*-
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* Copyright (c) 2000 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
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* NASA Ames Research Center.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*-
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* Copyright (c) 1982, 1986, 1991, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)kern_clock.c 8.5 (Berkeley) 1/21/94
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*/
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#include "opt_ntp.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/dkstat.h>
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#include <sys/callout.h>
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#include <sys/kernel.h>
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#include <sys/proc.h>
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#include <sys/resourcevar.h>
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#include <sys/signalvar.h>
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#include <uvm/uvm_extern.h>
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#include <sys/sysctl.h>
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#include <sys/timex.h>
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#include <sys/sched.h>
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#include <machine/cpu.h>
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#ifdef GPROF
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#include <sys/gmon.h>
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#endif
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/*
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* Clock handling routines.
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*
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* This code is written to operate with two timers that run independently of
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* each other. The main clock, running hz times per second, is used to keep
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* track of real time. The second timer handles kernel and user profiling,
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* and does resource use estimation. If the second timer is programmable,
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* it is randomized to avoid aliasing between the two clocks. For example,
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* the randomization prevents an adversary from always giving up the cpu
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* just before its quantum expires. Otherwise, it would never accumulate
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* cpu ticks. The mean frequency of the second timer is stathz.
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*
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* If no second timer exists, stathz will be zero; in this case we drive
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* profiling and statistics off the main clock. This WILL NOT be accurate;
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* do not do it unless absolutely necessary.
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*
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* The statistics clock may (or may not) be run at a higher rate while
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* profiling. This profile clock runs at profhz. We require that profhz
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* be an integral multiple of stathz.
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*
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* If the statistics clock is running fast, it must be divided by the ratio
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* profhz/stathz for statistics. (For profiling, every tick counts.)
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*/
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#ifdef NTP /* NTP phase-locked loop in kernel */
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/*
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* Phase/frequency-lock loop (PLL/FLL) definitions
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*
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* The following variables are read and set by the ntp_adjtime() system
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* call.
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*
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* time_state shows the state of the system clock, with values defined
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* in the timex.h header file.
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*
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* time_status shows the status of the system clock, with bits defined
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* in the timex.h header file.
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*
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* time_offset is used by the PLL/FLL to adjust the system time in small
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* increments.
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*
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* time_constant determines the bandwidth or "stiffness" of the PLL.
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*
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* time_tolerance determines maximum frequency error or tolerance of the
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* CPU clock oscillator and is a property of the architecture; however,
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* in principle it could change as result of the presence of external
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* discipline signals, for instance.
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*
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* time_precision is usually equal to the kernel tick variable; however,
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* in cases where a precision clock counter or external clock is
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* available, the resolution can be much less than this and depend on
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* whether the external clock is working or not.
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*
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* time_maxerror is initialized by a ntp_adjtime() call and increased by
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* the kernel once each second to reflect the maximum error bound
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* growth.
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*
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* time_esterror is set and read by the ntp_adjtime() call, but
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* otherwise not used by the kernel.
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*/
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int time_state = TIME_OK; /* clock state */
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int time_status = STA_UNSYNC; /* clock status bits */
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long time_offset = 0; /* time offset (us) */
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long time_constant = 0; /* pll time constant */
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long time_tolerance = MAXFREQ; /* frequency tolerance (scaled ppm) */
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long time_precision = 1; /* clock precision (us) */
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long time_maxerror = MAXPHASE; /* maximum error (us) */
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long time_esterror = MAXPHASE; /* estimated error (us) */
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/*
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* The following variables establish the state of the PLL/FLL and the
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* residual time and frequency offset of the local clock. The scale
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* factors are defined in the timex.h header file.
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*
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* time_phase and time_freq are the phase increment and the frequency
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* increment, respectively, of the kernel time variable.
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*
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* time_freq is set via ntp_adjtime() from a value stored in a file when
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* the synchronization daemon is first started. Its value is retrieved
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* via ntp_adjtime() and written to the file about once per hour by the
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* daemon.
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*
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* time_adj is the adjustment added to the value of tick at each timer
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* interrupt and is recomputed from time_phase and time_freq at each
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* seconds rollover.
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*
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* time_reftime is the second's portion of the system time at the last
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* call to ntp_adjtime(). It is used to adjust the time_freq variable
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* and to increase the time_maxerror as the time since last update
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* increases.
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*/
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long time_phase = 0; /* phase offset (scaled us) */
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long time_freq = 0; /* frequency offset (scaled ppm) */
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long time_adj = 0; /* tick adjust (scaled 1 / hz) */
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long time_reftime = 0; /* time at last adjustment (s) */
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#ifdef PPS_SYNC
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/*
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* The following variables are used only if the kernel PPS discipline
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* code is configured (PPS_SYNC). The scale factors are defined in the
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* timex.h header file.
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*
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* pps_time contains the time at each calibration interval, as read by
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* microtime(). pps_count counts the seconds of the calibration
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* interval, the duration of which is nominally pps_shift in powers of
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* two.
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*
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* pps_offset is the time offset produced by the time median filter
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* pps_tf[], while pps_jitter is the dispersion (jitter) measured by
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* this filter.
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*
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* pps_freq is the frequency offset produced by the frequency median
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* filter pps_ff[], while pps_stabil is the dispersion (wander) measured
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* by this filter.
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*
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* pps_usec is latched from a high resolution counter or external clock
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* at pps_time. Here we want the hardware counter contents only, not the
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* contents plus the time_tv.usec as usual.
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*
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* pps_valid counts the number of seconds since the last PPS update. It
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* is used as a watchdog timer to disable the PPS discipline should the
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* PPS signal be lost.
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*
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* pps_glitch counts the number of seconds since the beginning of an
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* offset burst more than tick/2 from current nominal offset. It is used
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* mainly to suppress error bursts due to priority conflicts between the
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* PPS interrupt and timer interrupt.
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*
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* pps_intcnt counts the calibration intervals for use in the interval-
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* adaptation algorithm. It's just too complicated for words.
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*/
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struct timeval pps_time; /* kernel time at last interval */
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long pps_tf[] = {0, 0, 0}; /* pps time offset median filter (us) */
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long pps_offset = 0; /* pps time offset (us) */
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long pps_jitter = MAXTIME; /* time dispersion (jitter) (us) */
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long pps_ff[] = {0, 0, 0}; /* pps frequency offset median filter */
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long pps_freq = 0; /* frequency offset (scaled ppm) */
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long pps_stabil = MAXFREQ; /* frequency dispersion (scaled ppm) */
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long pps_usec = 0; /* microsec counter at last interval */
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long pps_valid = PPS_VALID; /* pps signal watchdog counter */
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int pps_glitch = 0; /* pps signal glitch counter */
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int pps_count = 0; /* calibration interval counter (s) */
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int pps_shift = PPS_SHIFT; /* interval duration (s) (shift) */
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int pps_intcnt = 0; /* intervals at current duration */
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/*
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* PPS signal quality monitors
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*
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* pps_jitcnt counts the seconds that have been discarded because the
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* jitter measured by the time median filter exceeds the limit MAXTIME
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* (100 us).
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*
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* pps_calcnt counts the frequency calibration intervals, which are
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* variable from 4 s to 256 s.
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*
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* pps_errcnt counts the calibration intervals which have been discarded
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* because the wander exceeds the limit MAXFREQ (100 ppm) or where the
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* calibration interval jitter exceeds two ticks.
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*
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* pps_stbcnt counts the calibration intervals that have been discarded
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* because the frequency wander exceeds the limit MAXFREQ / 4 (25 us).
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*/
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long pps_jitcnt = 0; /* jitter limit exceeded */
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long pps_calcnt = 0; /* calibration intervals */
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long pps_errcnt = 0; /* calibration errors */
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long pps_stbcnt = 0; /* stability limit exceeded */
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#endif /* PPS_SYNC */
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#ifdef EXT_CLOCK
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/*
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* External clock definitions
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*
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* The following definitions and declarations are used only if an
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* external clock is configured on the system.
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*/
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#define CLOCK_INTERVAL 30 /* CPU clock update interval (s) */
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/*
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* The clock_count variable is set to CLOCK_INTERVAL at each PPS
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* interrupt and decremented once each second.
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*/
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int clock_count = 0; /* CPU clock counter */
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#ifdef HIGHBALL
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/*
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* The clock_offset and clock_cpu variables are used by the HIGHBALL
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* interface. The clock_offset variable defines the offset between
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* system time and the HIGBALL counters. The clock_cpu variable contains
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* the offset between the system clock and the HIGHBALL clock for use in
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* disciplining the kernel time variable.
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*/
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extern struct timeval clock_offset; /* Highball clock offset */
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long clock_cpu = 0; /* CPU clock adjust */
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#endif /* HIGHBALL */
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#endif /* EXT_CLOCK */
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#endif /* NTP */
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/*
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* Bump a timeval by a small number of usec's.
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*/
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#define BUMPTIME(t, usec) { \
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volatile struct timeval *tp = (t); \
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long us; \
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\
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tp->tv_usec = us = tp->tv_usec + (usec); \
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if (us >= 1000000) { \
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tp->tv_usec = us - 1000000; \
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tp->tv_sec++; \
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} \
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}
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int stathz;
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int profhz;
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int profprocs;
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int softclock_running; /* 1 => softclock() is running */
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static int psdiv; /* prof => stat divider */
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int psratio; /* ratio: prof / stat */
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int tickfix, tickfixinterval; /* used if tick not really integral */
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#ifndef NTP
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static int tickfixcnt; /* accumulated fractional error */
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#else
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int fixtick; /* used by NTP for same */
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int shifthz;
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#endif
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/*
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* We might want ldd to load the both words from time at once.
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* To succeed we need to be quadword aligned.
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* The sparc already does that, and that it has worked so far is a fluke.
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*/
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volatile struct timeval time __attribute__((__aligned__(__alignof__(quad_t))));
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volatile struct timeval mono_time;
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/*
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* The callout mechanism is based on the work of Adam M. Costello and
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* George Varghese, published in a technical report entitled "Redesigning
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* the BSD Callout and Timer Facilities", and Justin Gibbs's subsequent
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* integration into FreeBSD, modified for NetBSD by Jason R. Thorpe.
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*
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* The original work on the data structures used in this implementation
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* was published by G. Varghese and A. Lauck in the paper "Hashed and
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* Hierarchical Timing Wheels: Data Structures for the Efficient
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* Implementation of a Timer Facility" in the Proceedings of the 11th
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* ACM Annual Symposium on Operating System Principles, Austin, Texas,
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* November 1987.
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*/
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struct callout_queue *callwheel;
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int callwheelsize, callwheelbits, callwheelmask;
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static struct callout *nextsoftcheck; /* next callout to be checked */
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#ifdef CALLWHEEL_STATS
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int callwheel_collisions; /* number of hash collisions */
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int callwheel_maxlength; /* length of the longest hash chain */
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int *callwheel_sizes; /* per-bucket length count */
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u_int64_t callwheel_count; /* # callouts currently */
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u_int64_t callwheel_established; /* # callouts established */
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u_int64_t callwheel_fired; /* # callouts that fired */
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u_int64_t callwheel_disestablished; /* # callouts disestablished */
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u_int64_t callwheel_changed; /* # callouts changed */
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u_int64_t callwheel_softclocks; /* # times softclock() called */
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u_int64_t callwheel_softchecks; /* # checks per softclock() */
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u_int64_t callwheel_softempty; /* # empty buckets seen */
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#endif /* CALLWHEEL_STATS */
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/*
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* This value indicates the number of consecutive callouts that
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* will be checked before we allow interrupts to have a chance
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* again.
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*/
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#ifndef MAX_SOFTCLOCK_STEPS
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#define MAX_SOFTCLOCK_STEPS 100
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#endif
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struct simplelock callwheel_slock;
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#define CALLWHEEL_LOCK(s) \
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do { \
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s = splclock(); \
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simple_lock(&callwheel_slock); \
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} while (0)
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#define CALLWHEEL_UNLOCK(s) \
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do { \
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simple_unlock(&callwheel_slock); \
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splx(s); \
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} while (0)
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static void callout_stop_locked(struct callout *);
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/*
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* These are both protected by callwheel_lock.
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* XXX SHOULD BE STATIC!!
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*/
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u_int64_t hardclock_ticks, softclock_ticks;
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/*
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* Initialize clock frequencies and start both clocks running.
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*/
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void
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initclocks(void)
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{
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int i;
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/*
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* Set divisors to 1 (normal case) and let the machine-specific
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* code do its bit.
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*/
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psdiv = 1;
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cpu_initclocks();
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/*
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* Compute profhz/stathz/rrticks, and fix profhz if needed.
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*/
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i = stathz ? stathz : hz;
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if (profhz == 0)
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profhz = i;
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psratio = profhz / i;
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rrticks = hz / 10;
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#ifdef NTP
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switch (hz) {
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case 1:
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shifthz = SHIFT_SCALE - 0;
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break;
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case 2:
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shifthz = SHIFT_SCALE - 1;
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break;
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case 4:
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shifthz = SHIFT_SCALE - 2;
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break;
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case 8:
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shifthz = SHIFT_SCALE - 3;
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break;
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case 16:
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shifthz = SHIFT_SCALE - 4;
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break;
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case 32:
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shifthz = SHIFT_SCALE - 5;
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break;
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case 60:
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case 64:
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shifthz = SHIFT_SCALE - 6;
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break;
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case 96:
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case 100:
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case 128:
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shifthz = SHIFT_SCALE - 7;
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break;
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case 256:
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shifthz = SHIFT_SCALE - 8;
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break;
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case 512:
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shifthz = SHIFT_SCALE - 9;
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break;
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case 1000:
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case 1024:
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shifthz = SHIFT_SCALE - 10;
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break;
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case 1200:
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case 2048:
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shifthz = SHIFT_SCALE - 11;
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break;
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case 4096:
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shifthz = SHIFT_SCALE - 12;
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break;
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case 8192:
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shifthz = SHIFT_SCALE - 13;
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break;
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case 16384:
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shifthz = SHIFT_SCALE - 14;
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break;
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case 32768:
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shifthz = SHIFT_SCALE - 15;
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break;
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case 65536:
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shifthz = SHIFT_SCALE - 16;
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break;
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default:
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panic("weird hz");
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}
|
|
if (fixtick == 0) {
|
|
/*
|
|
* Give MD code a chance to set this to a better
|
|
* value; but, if it doesn't, we should.
|
|
*/
|
|
fixtick = (1000000 - (hz*tick));
|
|
}
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* The real-time timer, interrupting hz times per second.
|
|
*/
|
|
void
|
|
hardclock(struct clockframe *frame)
|
|
{
|
|
struct proc *p;
|
|
int delta;
|
|
extern int tickdelta;
|
|
extern long timedelta;
|
|
struct cpu_info *ci = curcpu();
|
|
#ifdef NTP
|
|
int time_update;
|
|
int ltemp;
|
|
#endif
|
|
|
|
p = curproc;
|
|
if (p) {
|
|
struct pstats *pstats;
|
|
|
|
/*
|
|
* Run current process's virtual and profile time, as needed.
|
|
*/
|
|
pstats = p->p_stats;
|
|
if (CLKF_USERMODE(frame) &&
|
|
timerisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value) &&
|
|
itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL], tick) == 0)
|
|
psignal(p, SIGVTALRM);
|
|
if (timerisset(&pstats->p_timer[ITIMER_PROF].it_value) &&
|
|
itimerdecr(&pstats->p_timer[ITIMER_PROF], tick) == 0)
|
|
psignal(p, SIGPROF);
|
|
}
|
|
|
|
/*
|
|
* If no separate statistics clock is available, run it from here.
|
|
*/
|
|
if (stathz == 0)
|
|
statclock(frame);
|
|
if ((--ci->ci_schedstate.spc_rrticks) <= 0)
|
|
roundrobin(ci);
|
|
|
|
#if defined(MULTIPROCESSOR)
|
|
/*
|
|
* If we are not the primary CPU, we're not allowed to do
|
|
* any more work.
|
|
*/
|
|
if (CPU_IS_PRIMARY(ci) == 0)
|
|
return;
|
|
#endif
|
|
|
|
/*
|
|
* Increment the time-of-day. The increment is normally just
|
|
* ``tick''. If the machine is one which has a clock frequency
|
|
* such that ``hz'' would not divide the second evenly into
|
|
* milliseconds, a periodic adjustment must be applied. Finally,
|
|
* if we are still adjusting the time (see adjtime()),
|
|
* ``tickdelta'' may also be added in.
|
|
*/
|
|
delta = tick;
|
|
|
|
#ifndef NTP
|
|
if (tickfix) {
|
|
tickfixcnt += tickfix;
|
|
if (tickfixcnt >= tickfixinterval) {
|
|
delta++;
|
|
tickfixcnt -= tickfixinterval;
|
|
}
|
|
}
|
|
#endif /* !NTP */
|
|
/* Imprecise 4bsd adjtime() handling */
|
|
if (timedelta != 0) {
|
|
delta += tickdelta;
|
|
timedelta -= tickdelta;
|
|
}
|
|
|
|
#ifdef notyet
|
|
microset();
|
|
#endif
|
|
|
|
#ifndef NTP
|
|
BUMPTIME(&time, delta); /* XXX Now done using NTP code below */
|
|
#endif
|
|
BUMPTIME(&mono_time, delta);
|
|
|
|
#ifdef NTP
|
|
time_update = delta;
|
|
|
|
/*
|
|
* Compute the phase adjustment. If the low-order bits
|
|
* (time_phase) of the update overflow, bump the high-order bits
|
|
* (time_update).
|
|
*/
|
|
time_phase += time_adj;
|
|
if (time_phase <= -FINEUSEC) {
|
|
ltemp = -time_phase >> SHIFT_SCALE;
|
|
time_phase += ltemp << SHIFT_SCALE;
|
|
time_update -= ltemp;
|
|
} else if (time_phase >= FINEUSEC) {
|
|
ltemp = time_phase >> SHIFT_SCALE;
|
|
time_phase -= ltemp << SHIFT_SCALE;
|
|
time_update += ltemp;
|
|
}
|
|
|
|
#ifdef HIGHBALL
|
|
/*
|
|
* If the HIGHBALL board is installed, we need to adjust the
|
|
* external clock offset in order to close the hardware feedback
|
|
* loop. This will adjust the external clock phase and frequency
|
|
* in small amounts. The additional phase noise and frequency
|
|
* wander this causes should be minimal. We also need to
|
|
* discipline the kernel time variable, since the PLL is used to
|
|
* discipline the external clock. If the Highball board is not
|
|
* present, we discipline kernel time with the PLL as usual. We
|
|
* assume that the external clock phase adjustment (time_update)
|
|
* and kernel phase adjustment (clock_cpu) are less than the
|
|
* value of tick.
|
|
*/
|
|
clock_offset.tv_usec += time_update;
|
|
if (clock_offset.tv_usec >= 1000000) {
|
|
clock_offset.tv_sec++;
|
|
clock_offset.tv_usec -= 1000000;
|
|
}
|
|
if (clock_offset.tv_usec < 0) {
|
|
clock_offset.tv_sec--;
|
|
clock_offset.tv_usec += 1000000;
|
|
}
|
|
time.tv_usec += clock_cpu;
|
|
clock_cpu = 0;
|
|
#else
|
|
time.tv_usec += time_update;
|
|
#endif /* HIGHBALL */
|
|
|
|
/*
|
|
* On rollover of the second the phase adjustment to be used for
|
|
* the next second is calculated. Also, the maximum error is
|
|
* increased by the tolerance. If the PPS frequency discipline
|
|
* code is present, the phase is increased to compensate for the
|
|
* CPU clock oscillator frequency error.
|
|
*
|
|
* On a 32-bit machine and given parameters in the timex.h
|
|
* header file, the maximum phase adjustment is +-512 ms and
|
|
* maximum frequency offset is a tad less than) +-512 ppm. On a
|
|
* 64-bit machine, you shouldn't need to ask.
|
|
*/
|
|
if (time.tv_usec >= 1000000) {
|
|
time.tv_usec -= 1000000;
|
|
time.tv_sec++;
|
|
time_maxerror += time_tolerance >> SHIFT_USEC;
|
|
|
|
/*
|
|
* Leap second processing. If in leap-insert state at
|
|
* the end of the day, the system clock is set back one
|
|
* second; if in leap-delete state, the system clock is
|
|
* set ahead one second. The microtime() routine or
|
|
* external clock driver will insure that reported time
|
|
* is always monotonic. The ugly divides should be
|
|
* replaced.
|
|
*/
|
|
switch (time_state) {
|
|
case TIME_OK:
|
|
if (time_status & STA_INS)
|
|
time_state = TIME_INS;
|
|
else if (time_status & STA_DEL)
|
|
time_state = TIME_DEL;
|
|
break;
|
|
|
|
case TIME_INS:
|
|
if (time.tv_sec % 86400 == 0) {
|
|
time.tv_sec--;
|
|
time_state = TIME_OOP;
|
|
}
|
|
break;
|
|
|
|
case TIME_DEL:
|
|
if ((time.tv_sec + 1) % 86400 == 0) {
|
|
time.tv_sec++;
|
|
time_state = TIME_WAIT;
|
|
}
|
|
break;
|
|
|
|
case TIME_OOP:
|
|
time_state = TIME_WAIT;
|
|
break;
|
|
|
|
case TIME_WAIT:
|
|
if (!(time_status & (STA_INS | STA_DEL)))
|
|
time_state = TIME_OK;
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Compute the phase adjustment for the next second. In
|
|
* PLL mode, the offset is reduced by a fixed factor
|
|
* times the time constant. In FLL mode the offset is
|
|
* used directly. In either mode, the maximum phase
|
|
* adjustment for each second is clamped so as to spread
|
|
* the adjustment over not more than the number of
|
|
* seconds between updates.
|
|
*/
|
|
if (time_offset < 0) {
|
|
ltemp = -time_offset;
|
|
if (!(time_status & STA_FLL))
|
|
ltemp >>= SHIFT_KG + time_constant;
|
|
if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE)
|
|
ltemp = (MAXPHASE / MINSEC) <<
|
|
SHIFT_UPDATE;
|
|
time_offset += ltemp;
|
|
time_adj = -ltemp << (shifthz - SHIFT_UPDATE);
|
|
} else if (time_offset > 0) {
|
|
ltemp = time_offset;
|
|
if (!(time_status & STA_FLL))
|
|
ltemp >>= SHIFT_KG + time_constant;
|
|
if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE)
|
|
ltemp = (MAXPHASE / MINSEC) <<
|
|
SHIFT_UPDATE;
|
|
time_offset -= ltemp;
|
|
time_adj = ltemp << (shifthz - SHIFT_UPDATE);
|
|
} else
|
|
time_adj = 0;
|
|
|
|
/*
|
|
* Compute the frequency estimate and additional phase
|
|
* adjustment due to frequency error for the next
|
|
* second. When the PPS signal is engaged, gnaw on the
|
|
* watchdog counter and update the frequency computed by
|
|
* the pll and the PPS signal.
|
|
*/
|
|
#ifdef PPS_SYNC
|
|
pps_valid++;
|
|
if (pps_valid == PPS_VALID) {
|
|
pps_jitter = MAXTIME;
|
|
pps_stabil = MAXFREQ;
|
|
time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER |
|
|
STA_PPSWANDER | STA_PPSERROR);
|
|
}
|
|
ltemp = time_freq + pps_freq;
|
|
#else
|
|
ltemp = time_freq;
|
|
#endif /* PPS_SYNC */
|
|
|
|
if (ltemp < 0)
|
|
time_adj -= -ltemp >> (SHIFT_USEC - shifthz);
|
|
else
|
|
time_adj += ltemp >> (SHIFT_USEC - shifthz);
|
|
time_adj += (long)fixtick << shifthz;
|
|
|
|
/*
|
|
* When the CPU clock oscillator frequency is not a
|
|
* power of 2 in Hz, shifthz is only an approximate
|
|
* scale factor.
|
|
*
|
|
* To determine the adjustment, you can do the following:
|
|
* bc -q
|
|
* scale=24
|
|
* obase=2
|
|
* idealhz/realhz
|
|
* where `idealhz' is the next higher power of 2, and `realhz'
|
|
* is the actual value. You may need to factor this result
|
|
* into a sequence of 2 multipliers to get better precision.
|
|
*
|
|
* Likewise, the error can be calculated with (e.g. for 100Hz):
|
|
* bc -q
|
|
* scale=24
|
|
* ((1+2^-2+2^-5)*(1-2^-10)*realhz-idealhz)/idealhz
|
|
* (and then multiply by 1000000 to get ppm).
|
|
*/
|
|
switch (hz) {
|
|
case 60:
|
|
/* A factor of 1.000100010001 gives about 15ppm
|
|
error. */
|
|
if (time_adj < 0) {
|
|
time_adj -= (-time_adj >> 4);
|
|
time_adj -= (-time_adj >> 8);
|
|
} else {
|
|
time_adj += (time_adj >> 4);
|
|
time_adj += (time_adj >> 8);
|
|
}
|
|
break;
|
|
|
|
case 96:
|
|
/* A factor of 1.0101010101 gives about 244ppm error. */
|
|
if (time_adj < 0) {
|
|
time_adj -= (-time_adj >> 2);
|
|
time_adj -= (-time_adj >> 4) + (-time_adj >> 8);
|
|
} else {
|
|
time_adj += (time_adj >> 2);
|
|
time_adj += (time_adj >> 4) + (time_adj >> 8);
|
|
}
|
|
break;
|
|
|
|
case 100:
|
|
/* A factor of 1.010001111010111 gives about 1ppm
|
|
error. */
|
|
if (time_adj < 0) {
|
|
time_adj -= (-time_adj >> 2) + (-time_adj >> 5);
|
|
time_adj += (-time_adj >> 10);
|
|
} else {
|
|
time_adj += (time_adj >> 2) + (time_adj >> 5);
|
|
time_adj -= (time_adj >> 10);
|
|
}
|
|
break;
|
|
|
|
case 1000:
|
|
/* A factor of 1.000001100010100001 gives about 50ppm
|
|
error. */
|
|
if (time_adj < 0) {
|
|
time_adj -= (-time_adj >> 6) + (-time_adj >> 11);
|
|
time_adj -= (-time_adj >> 7);
|
|
} else {
|
|
time_adj += (time_adj >> 6) + (time_adj >> 11);
|
|
time_adj += (time_adj >> 7);
|
|
}
|
|
break;
|
|
|
|
case 1200:
|
|
/* A factor of 1.1011010011100001 gives about 64ppm
|
|
error. */
|
|
if (time_adj < 0) {
|
|
time_adj -= (-time_adj >> 1) + (-time_adj >> 6);
|
|
time_adj -= (-time_adj >> 3) + (-time_adj >> 10);
|
|
} else {
|
|
time_adj += (time_adj >> 1) + (time_adj >> 6);
|
|
time_adj += (time_adj >> 3) + (time_adj >> 10);
|
|
}
|
|
break;
|
|
}
|
|
|
|
#ifdef EXT_CLOCK
|
|
/*
|
|
* If an external clock is present, it is necessary to
|
|
* discipline the kernel time variable anyway, since not
|
|
* all system components use the microtime() interface.
|
|
* Here, the time offset between the external clock and
|
|
* kernel time variable is computed every so often.
|
|
*/
|
|
clock_count++;
|
|
if (clock_count > CLOCK_INTERVAL) {
|
|
clock_count = 0;
|
|
microtime(&clock_ext);
|
|
delta.tv_sec = clock_ext.tv_sec - time.tv_sec;
|
|
delta.tv_usec = clock_ext.tv_usec -
|
|
time.tv_usec;
|
|
if (delta.tv_usec < 0)
|
|
delta.tv_sec--;
|
|
if (delta.tv_usec >= 500000) {
|
|
delta.tv_usec -= 1000000;
|
|
delta.tv_sec++;
|
|
}
|
|
if (delta.tv_usec < -500000) {
|
|
delta.tv_usec += 1000000;
|
|
delta.tv_sec--;
|
|
}
|
|
if (delta.tv_sec > 0 || (delta.tv_sec == 0 &&
|
|
delta.tv_usec > MAXPHASE) ||
|
|
delta.tv_sec < -1 || (delta.tv_sec == -1 &&
|
|
delta.tv_usec < -MAXPHASE)) {
|
|
time = clock_ext;
|
|
delta.tv_sec = 0;
|
|
delta.tv_usec = 0;
|
|
}
|
|
#ifdef HIGHBALL
|
|
clock_cpu = delta.tv_usec;
|
|
#else /* HIGHBALL */
|
|
hardupdate(delta.tv_usec);
|
|
#endif /* HIGHBALL */
|
|
}
|
|
#endif /* EXT_CLOCK */
|
|
}
|
|
|
|
#endif /* NTP */
|
|
|
|
/*
|
|
* Process callouts at a very low cpu priority, so we don't keep the
|
|
* relatively high clock interrupt priority any longer than necessary.
|
|
*/
|
|
simple_lock(&callwheel_slock); /* already at splclock() */
|
|
hardclock_ticks++;
|
|
if (TAILQ_FIRST(&callwheel[hardclock_ticks & callwheelmask]) != NULL) {
|
|
simple_unlock(&callwheel_slock);
|
|
if (CLKF_BASEPRI(frame)) {
|
|
/*
|
|
* Save the overhead of a software interrupt;
|
|
* it will happen as soon as we return, so do
|
|
* it now.
|
|
*
|
|
* NOTE: If we're at ``base priority'', softclock()
|
|
* was not already running.
|
|
*/
|
|
spllowersoftclock();
|
|
KERNEL_LOCK(LK_CANRECURSE|LK_EXCLUSIVE);
|
|
softclock();
|
|
KERNEL_UNLOCK();
|
|
} else
|
|
setsoftclock();
|
|
return;
|
|
} else if (softclock_running == 0 &&
|
|
(softclock_ticks + 1) == hardclock_ticks) {
|
|
softclock_ticks++;
|
|
}
|
|
simple_unlock(&callwheel_slock);
|
|
}
|
|
|
|
/*
|
|
* Software (low priority) clock interrupt.
|
|
* Run periodic events from timeout queue.
|
|
*/
|
|
/*ARGSUSED*/
|
|
void
|
|
softclock(void)
|
|
{
|
|
struct callout_queue *bucket;
|
|
struct callout *c;
|
|
void (*func)(void *);
|
|
void *arg;
|
|
int s, idx;
|
|
int steps = 0;
|
|
|
|
CALLWHEEL_LOCK(s);
|
|
|
|
softclock_running = 1;
|
|
|
|
#ifdef CALLWHEEL_STATS
|
|
callwheel_softclocks++;
|
|
#endif
|
|
|
|
while (softclock_ticks != hardclock_ticks) {
|
|
softclock_ticks++;
|
|
idx = (int)(softclock_ticks & callwheelmask);
|
|
bucket = &callwheel[idx];
|
|
c = TAILQ_FIRST(bucket);
|
|
#ifdef CALLWHEEL_STATS
|
|
if (c == NULL)
|
|
callwheel_softempty++;
|
|
#endif
|
|
while (c != NULL) {
|
|
#ifdef CALLWHEEL_STATS
|
|
callwheel_softchecks++;
|
|
#endif
|
|
if (c->c_time != softclock_ticks) {
|
|
c = TAILQ_NEXT(c, c_link);
|
|
if (++steps >= MAX_SOFTCLOCK_STEPS) {
|
|
nextsoftcheck = c;
|
|
/* Give interrupts a chance. */
|
|
CALLWHEEL_UNLOCK(s);
|
|
CALLWHEEL_LOCK(s);
|
|
c = nextsoftcheck;
|
|
steps = 0;
|
|
}
|
|
} else {
|
|
nextsoftcheck = TAILQ_NEXT(c, c_link);
|
|
TAILQ_REMOVE(bucket, c, c_link);
|
|
#ifdef CALLWHEEL_STATS
|
|
callwheel_sizes[idx]--;
|
|
callwheel_fired++;
|
|
callwheel_count--;
|
|
#endif
|
|
func = c->c_func;
|
|
arg = c->c_arg;
|
|
c->c_func = NULL;
|
|
c->c_flags &= ~CALLOUT_PENDING;
|
|
CALLWHEEL_UNLOCK(s);
|
|
(*func)(arg);
|
|
CALLWHEEL_LOCK(s);
|
|
steps = 0;
|
|
c = nextsoftcheck;
|
|
}
|
|
}
|
|
}
|
|
nextsoftcheck = NULL;
|
|
softclock_running = 0;
|
|
CALLWHEEL_UNLOCK(s);
|
|
}
|
|
|
|
/*
|
|
* callout_setsize:
|
|
*
|
|
* Determine how many callwheels are necessary and
|
|
* set hash mask. Called from allocsys().
|
|
*/
|
|
void
|
|
callout_setsize(void)
|
|
{
|
|
|
|
for (callwheelsize = 1; callwheelsize < ncallout; callwheelsize <<= 1)
|
|
/* loop */ ;
|
|
callwheelmask = callwheelsize - 1;
|
|
}
|
|
|
|
/*
|
|
* callout_startup:
|
|
*
|
|
* Initialize the callwheel buckets.
|
|
*/
|
|
void
|
|
callout_startup(void)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < callwheelsize; i++)
|
|
TAILQ_INIT(&callwheel[i]);
|
|
|
|
simple_lock_init(&callwheel_slock);
|
|
}
|
|
|
|
/*
|
|
* callout_init:
|
|
*
|
|
* Initialize a callout structure so that it can be used
|
|
* by callout_reset() and callout_stop().
|
|
*/
|
|
void
|
|
callout_init(struct callout *c)
|
|
{
|
|
|
|
memset(c, 0, sizeof(*c));
|
|
}
|
|
|
|
/*
|
|
* callout_reset:
|
|
*
|
|
* Establish or change a timeout.
|
|
*/
|
|
void
|
|
callout_reset(struct callout *c, int ticks, void (*func)(void *), void *arg)
|
|
{
|
|
struct callout_queue *bucket;
|
|
int s;
|
|
|
|
if (ticks <= 0)
|
|
ticks = 1;
|
|
|
|
CALLWHEEL_LOCK(s);
|
|
|
|
/*
|
|
* If this callout's timer is already running, cancel it
|
|
* before we modify it.
|
|
*/
|
|
if (c->c_flags & CALLOUT_PENDING) {
|
|
callout_stop_locked(c); /* Already locked */
|
|
#ifdef CALLWHEEL_STATS
|
|
callwheel_changed++;
|
|
#endif
|
|
}
|
|
|
|
c->c_arg = arg;
|
|
c->c_func = func;
|
|
c->c_flags = CALLOUT_ACTIVE | CALLOUT_PENDING;
|
|
c->c_time = hardclock_ticks + ticks;
|
|
|
|
bucket = &callwheel[c->c_time & callwheelmask];
|
|
|
|
#ifdef CALLWHEEL_STATS
|
|
if (TAILQ_FIRST(bucket) != NULL)
|
|
callwheel_collisions++;
|
|
#endif
|
|
|
|
TAILQ_INSERT_TAIL(bucket, c, c_link);
|
|
|
|
#ifdef CALLWHEEL_STATS
|
|
callwheel_count++;
|
|
callwheel_established++;
|
|
if (++callwheel_sizes[c->c_time & callwheelmask] > callwheel_maxlength)
|
|
callwheel_maxlength =
|
|
callwheel_sizes[c->c_time & callwheelmask];
|
|
#endif
|
|
|
|
CALLWHEEL_UNLOCK(s);
|
|
}
|
|
|
|
/*
|
|
* callout_stop_locked:
|
|
*
|
|
* Disestablish a timeout. Callwheel is locked.
|
|
*/
|
|
static void
|
|
callout_stop_locked(struct callout *c)
|
|
{
|
|
|
|
/*
|
|
* Don't attempt to delete a callout that's not on the queue.
|
|
*/
|
|
if ((c->c_flags & CALLOUT_PENDING) == 0) {
|
|
c->c_flags &= ~CALLOUT_ACTIVE;
|
|
return;
|
|
}
|
|
|
|
c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING);
|
|
|
|
if (nextsoftcheck == c)
|
|
nextsoftcheck = TAILQ_NEXT(c, c_link);
|
|
|
|
TAILQ_REMOVE(&callwheel[c->c_time & callwheelmask], c, c_link);
|
|
#ifdef CALLWHEEL_STATS
|
|
callwheel_count--;
|
|
callwheel_disestablished++;
|
|
callwheel_sizes[c->c_time & callwheelmask]--;
|
|
#endif
|
|
|
|
c->c_func = NULL;
|
|
}
|
|
|
|
/*
|
|
* callout_stop:
|
|
*
|
|
* Disestablish a timeout. Callwheel is unlocked. This is
|
|
* the standard entry point.
|
|
*/
|
|
void
|
|
callout_stop(struct callout *c)
|
|
{
|
|
int s;
|
|
|
|
CALLWHEEL_LOCK(s);
|
|
callout_stop_locked(c);
|
|
CALLWHEEL_UNLOCK(s);
|
|
}
|
|
|
|
#ifdef CALLWHEEL_STATS
|
|
/*
|
|
* callout_showstats:
|
|
*
|
|
* Display callout statistics. Call it from DDB.
|
|
*/
|
|
void
|
|
callout_showstats(void)
|
|
{
|
|
u_int64_t curticks;
|
|
int s;
|
|
|
|
s = splclock();
|
|
curticks = softclock_ticks;
|
|
splx(s);
|
|
|
|
printf("Callwheel statistics:\n");
|
|
printf("\tCallouts currently queued: %llu\n", callwheel_count);
|
|
printf("\tCallouts established: %llu\n", callwheel_established);
|
|
printf("\tCallouts disestablished: %llu\n", callwheel_disestablished);
|
|
if (callwheel_changed != 0)
|
|
printf("\t\tOf those, %llu were changes\n", callwheel_changed);
|
|
printf("\tCallouts that fired: %llu\n", callwheel_fired);
|
|
printf("\tNumber of buckets: %d\n", callwheelsize);
|
|
printf("\tNumber of hash collisions: %d\n", callwheel_collisions);
|
|
printf("\tMaximum hash chain length: %d\n", callwheel_maxlength);
|
|
printf("\tSoftclocks: %llu, Softchecks: %llu\n",
|
|
callwheel_softclocks, callwheel_softchecks);
|
|
printf("\t\tEmpty buckets seen: %llu\n", callwheel_softempty);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Compute number of hz until specified time. Used to compute second
|
|
* argument to callout_reset() from an absolute time.
|
|
*/
|
|
int
|
|
hzto(struct timeval *tv)
|
|
{
|
|
unsigned long ticks;
|
|
long sec, usec;
|
|
int s;
|
|
|
|
/*
|
|
* If the number of usecs in the whole seconds part of the time
|
|
* difference fits in a long, then the total number of usecs will
|
|
* fit in an unsigned long. Compute the total and convert it to
|
|
* ticks, rounding up and adding 1 to allow for the current tick
|
|
* to expire. Rounding also depends on unsigned long arithmetic
|
|
* to avoid overflow.
|
|
*
|
|
* Otherwise, if the number of ticks in the whole seconds part of
|
|
* the time difference fits in a long, then convert the parts to
|
|
* ticks separately and add, using similar rounding methods and
|
|
* overflow avoidance. This method would work in the previous
|
|
* case, but it is slightly slower and assume that hz is integral.
|
|
*
|
|
* Otherwise, round the time difference down to the maximum
|
|
* representable value.
|
|
*
|
|
* If ints are 32-bit, then the maximum value for any timeout in
|
|
* 10ms ticks is 248 days.
|
|
*/
|
|
s = splclock();
|
|
sec = tv->tv_sec - time.tv_sec;
|
|
usec = tv->tv_usec - time.tv_usec;
|
|
splx(s);
|
|
|
|
if (usec < 0) {
|
|
sec--;
|
|
usec += 1000000;
|
|
}
|
|
|
|
if (sec < 0 || (sec == 0 && usec <= 0)) {
|
|
/*
|
|
* Would expire now or in the past. Return 0 ticks.
|
|
* This is different from the legacy hzto() interface,
|
|
* and callers need to check for it.
|
|
*/
|
|
ticks = 0;
|
|
} else if (sec <= (LONG_MAX / 1000000))
|
|
ticks = (((sec * 1000000) + (unsigned long)usec + (tick - 1))
|
|
/ tick) + 1;
|
|
else if (sec <= (LONG_MAX / hz))
|
|
ticks = (sec * hz) +
|
|
(((unsigned long)usec + (tick - 1)) / tick) + 1;
|
|
else
|
|
ticks = LONG_MAX;
|
|
|
|
if (ticks > INT_MAX)
|
|
ticks = INT_MAX;
|
|
|
|
return ((int)ticks);
|
|
}
|
|
|
|
/*
|
|
* Start profiling on a process.
|
|
*
|
|
* Kernel profiling passes proc0 which never exits and hence
|
|
* keeps the profile clock running constantly.
|
|
*/
|
|
void
|
|
startprofclock(struct proc *p)
|
|
{
|
|
|
|
if ((p->p_flag & P_PROFIL) == 0) {
|
|
p->p_flag |= P_PROFIL;
|
|
if (++profprocs == 1 && stathz != 0)
|
|
psdiv = psratio;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Stop profiling on a process.
|
|
*/
|
|
void
|
|
stopprofclock(struct proc *p)
|
|
{
|
|
|
|
if (p->p_flag & P_PROFIL) {
|
|
p->p_flag &= ~P_PROFIL;
|
|
if (--profprocs == 0 && stathz != 0)
|
|
psdiv = 1;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Statistics clock. Grab profile sample, and if divider reaches 0,
|
|
* do process and kernel statistics.
|
|
*/
|
|
void
|
|
statclock(struct clockframe *frame)
|
|
{
|
|
#ifdef GPROF
|
|
struct gmonparam *g;
|
|
intptr_t i;
|
|
#endif
|
|
struct cpu_info *ci = curcpu();
|
|
struct schedstate_percpu *spc = &ci->ci_schedstate;
|
|
struct proc *p;
|
|
|
|
/*
|
|
* Notice changes in divisor frequency, and adjust clock
|
|
* frequency accordingly.
|
|
*/
|
|
if (spc->spc_psdiv != psdiv) {
|
|
spc->spc_psdiv = psdiv;
|
|
spc->spc_pscnt = psdiv;
|
|
if (psdiv == 1) {
|
|
setstatclockrate(stathz);
|
|
} else {
|
|
setstatclockrate(profhz);
|
|
}
|
|
}
|
|
if (CLKF_USERMODE(frame)) {
|
|
p = curproc;
|
|
if (p->p_flag & P_PROFIL)
|
|
addupc_intr(p, CLKF_PC(frame), 1);
|
|
if (--spc->spc_pscnt > 0)
|
|
return;
|
|
/*
|
|
* Came from user mode; CPU was in user state.
|
|
* If this process is being profiled record the tick.
|
|
*/
|
|
p->p_uticks++;
|
|
if (p->p_nice > NZERO)
|
|
spc->spc_cp_time[CP_NICE]++;
|
|
else
|
|
spc->spc_cp_time[CP_USER]++;
|
|
} else {
|
|
#ifdef GPROF
|
|
/*
|
|
* Kernel statistics are just like addupc_intr, only easier.
|
|
*/
|
|
g = &_gmonparam;
|
|
if (g->state == GMON_PROF_ON) {
|
|
i = CLKF_PC(frame) - g->lowpc;
|
|
if (i < g->textsize) {
|
|
i /= HISTFRACTION * sizeof(*g->kcount);
|
|
g->kcount[i]++;
|
|
}
|
|
}
|
|
#endif
|
|
if (--spc->spc_pscnt > 0)
|
|
return;
|
|
/*
|
|
* Came from kernel mode, so we were:
|
|
* - handling an interrupt,
|
|
* - doing syscall or trap work on behalf of the current
|
|
* user process, or
|
|
* - spinning in the idle loop.
|
|
* Whichever it is, charge the time as appropriate.
|
|
* Note that we charge interrupts to the current process,
|
|
* regardless of whether they are ``for'' that process,
|
|
* so that we know how much of its real time was spent
|
|
* in ``non-process'' (i.e., interrupt) work.
|
|
*/
|
|
p = curproc;
|
|
if (CLKF_INTR(frame)) {
|
|
if (p != NULL)
|
|
p->p_iticks++;
|
|
spc->spc_cp_time[CP_INTR]++;
|
|
} else if (p != NULL) {
|
|
p->p_sticks++;
|
|
spc->spc_cp_time[CP_SYS]++;
|
|
} else
|
|
spc->spc_cp_time[CP_IDLE]++;
|
|
}
|
|
spc->spc_pscnt = psdiv;
|
|
|
|
if (p != NULL) {
|
|
++p->p_cpticks;
|
|
/*
|
|
* If no separate schedclock is provided, call it here
|
|
* at ~~12-25 Hz, ~~16 Hz is best
|
|
*/
|
|
if (schedhz == 0)
|
|
if ((++ci->ci_schedstate.spc_schedticks & 3) == 0)
|
|
schedclock(p);
|
|
}
|
|
}
|
|
|
|
|
|
#ifdef NTP /* NTP phase-locked loop in kernel */
|
|
|
|
/*
|
|
* hardupdate() - local clock update
|
|
*
|
|
* This routine is called by ntp_adjtime() to update the local clock
|
|
* phase and frequency. The implementation is of an adaptive-parameter,
|
|
* hybrid phase/frequency-lock loop (PLL/FLL). The routine computes new
|
|
* time and frequency offset estimates for each call. If the kernel PPS
|
|
* discipline code is configured (PPS_SYNC), the PPS signal itself
|
|
* determines the new time offset, instead of the calling argument.
|
|
* Presumably, calls to ntp_adjtime() occur only when the caller
|
|
* believes the local clock is valid within some bound (+-128 ms with
|
|
* NTP). If the caller's time is far different than the PPS time, an
|
|
* argument will ensue, and it's not clear who will lose.
|
|
*
|
|
* For uncompensated quartz crystal oscillatores and nominal update
|
|
* intervals less than 1024 s, operation should be in phase-lock mode
|
|
* (STA_FLL = 0), where the loop is disciplined to phase. For update
|
|
* intervals greater than thiss, operation should be in frequency-lock
|
|
* mode (STA_FLL = 1), where the loop is disciplined to frequency.
|
|
*
|
|
* Note: splclock() is in effect.
|
|
*/
|
|
void
|
|
hardupdate(long offset)
|
|
{
|
|
long ltemp, mtemp;
|
|
|
|
if (!(time_status & STA_PLL) && !(time_status & STA_PPSTIME))
|
|
return;
|
|
ltemp = offset;
|
|
#ifdef PPS_SYNC
|
|
if (time_status & STA_PPSTIME && time_status & STA_PPSSIGNAL)
|
|
ltemp = pps_offset;
|
|
#endif /* PPS_SYNC */
|
|
|
|
/*
|
|
* Scale the phase adjustment and clamp to the operating range.
|
|
*/
|
|
if (ltemp > MAXPHASE)
|
|
time_offset = MAXPHASE << SHIFT_UPDATE;
|
|
else if (ltemp < -MAXPHASE)
|
|
time_offset = -(MAXPHASE << SHIFT_UPDATE);
|
|
else
|
|
time_offset = ltemp << SHIFT_UPDATE;
|
|
|
|
/*
|
|
* Select whether the frequency is to be controlled and in which
|
|
* mode (PLL or FLL). Clamp to the operating range. Ugly
|
|
* multiply/divide should be replaced someday.
|
|
*/
|
|
if (time_status & STA_FREQHOLD || time_reftime == 0)
|
|
time_reftime = time.tv_sec;
|
|
mtemp = time.tv_sec - time_reftime;
|
|
time_reftime = time.tv_sec;
|
|
if (time_status & STA_FLL) {
|
|
if (mtemp >= MINSEC) {
|
|
ltemp = ((time_offset / mtemp) << (SHIFT_USEC -
|
|
SHIFT_UPDATE));
|
|
if (ltemp < 0)
|
|
time_freq -= -ltemp >> SHIFT_KH;
|
|
else
|
|
time_freq += ltemp >> SHIFT_KH;
|
|
}
|
|
} else {
|
|
if (mtemp < MAXSEC) {
|
|
ltemp *= mtemp;
|
|
if (ltemp < 0)
|
|
time_freq -= -ltemp >> (time_constant +
|
|
time_constant + SHIFT_KF -
|
|
SHIFT_USEC);
|
|
else
|
|
time_freq += ltemp >> (time_constant +
|
|
time_constant + SHIFT_KF -
|
|
SHIFT_USEC);
|
|
}
|
|
}
|
|
if (time_freq > time_tolerance)
|
|
time_freq = time_tolerance;
|
|
else if (time_freq < -time_tolerance)
|
|
time_freq = -time_tolerance;
|
|
}
|
|
|
|
#ifdef PPS_SYNC
|
|
/*
|
|
* hardpps() - discipline CPU clock oscillator to external PPS signal
|
|
*
|
|
* This routine is called at each PPS interrupt in order to discipline
|
|
* the CPU clock oscillator to the PPS signal. It measures the PPS phase
|
|
* and leaves it in a handy spot for the hardclock() routine. It
|
|
* integrates successive PPS phase differences and calculates the
|
|
* frequency offset. This is used in hardclock() to discipline the CPU
|
|
* clock oscillator so that intrinsic frequency error is cancelled out.
|
|
* The code requires the caller to capture the time and hardware counter
|
|
* value at the on-time PPS signal transition.
|
|
*
|
|
* Note that, on some Unix systems, this routine runs at an interrupt
|
|
* priority level higher than the timer interrupt routine hardclock().
|
|
* Therefore, the variables used are distinct from the hardclock()
|
|
* variables, except for certain exceptions: The PPS frequency pps_freq
|
|
* and phase pps_offset variables are determined by this routine and
|
|
* updated atomically. The time_tolerance variable can be considered a
|
|
* constant, since it is infrequently changed, and then only when the
|
|
* PPS signal is disabled. The watchdog counter pps_valid is updated
|
|
* once per second by hardclock() and is atomically cleared in this
|
|
* routine.
|
|
*/
|
|
void
|
|
hardpps(struct timeval *tvp, /* time at PPS */
|
|
long usec /* hardware counter at PPS */)
|
|
{
|
|
long u_usec, v_usec, bigtick;
|
|
long cal_sec, cal_usec;
|
|
|
|
/*
|
|
* An occasional glitch can be produced when the PPS interrupt
|
|
* occurs in the hardclock() routine before the time variable is
|
|
* updated. Here the offset is discarded when the difference
|
|
* between it and the last one is greater than tick/2, but not
|
|
* if the interval since the first discard exceeds 30 s.
|
|
*/
|
|
time_status |= STA_PPSSIGNAL;
|
|
time_status &= ~(STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR);
|
|
pps_valid = 0;
|
|
u_usec = -tvp->tv_usec;
|
|
if (u_usec < -500000)
|
|
u_usec += 1000000;
|
|
v_usec = pps_offset - u_usec;
|
|
if (v_usec < 0)
|
|
v_usec = -v_usec;
|
|
if (v_usec > (tick >> 1)) {
|
|
if (pps_glitch > MAXGLITCH) {
|
|
pps_glitch = 0;
|
|
pps_tf[2] = u_usec;
|
|
pps_tf[1] = u_usec;
|
|
} else {
|
|
pps_glitch++;
|
|
u_usec = pps_offset;
|
|
}
|
|
} else
|
|
pps_glitch = 0;
|
|
|
|
/*
|
|
* A three-stage median filter is used to help deglitch the pps
|
|
* time. The median sample becomes the time offset estimate; the
|
|
* difference between the other two samples becomes the time
|
|
* dispersion (jitter) estimate.
|
|
*/
|
|
pps_tf[2] = pps_tf[1];
|
|
pps_tf[1] = pps_tf[0];
|
|
pps_tf[0] = u_usec;
|
|
if (pps_tf[0] > pps_tf[1]) {
|
|
if (pps_tf[1] > pps_tf[2]) {
|
|
pps_offset = pps_tf[1]; /* 0 1 2 */
|
|
v_usec = pps_tf[0] - pps_tf[2];
|
|
} else if (pps_tf[2] > pps_tf[0]) {
|
|
pps_offset = pps_tf[0]; /* 2 0 1 */
|
|
v_usec = pps_tf[2] - pps_tf[1];
|
|
} else {
|
|
pps_offset = pps_tf[2]; /* 0 2 1 */
|
|
v_usec = pps_tf[0] - pps_tf[1];
|
|
}
|
|
} else {
|
|
if (pps_tf[1] < pps_tf[2]) {
|
|
pps_offset = pps_tf[1]; /* 2 1 0 */
|
|
v_usec = pps_tf[2] - pps_tf[0];
|
|
} else if (pps_tf[2] < pps_tf[0]) {
|
|
pps_offset = pps_tf[0]; /* 1 0 2 */
|
|
v_usec = pps_tf[1] - pps_tf[2];
|
|
} else {
|
|
pps_offset = pps_tf[2]; /* 1 2 0 */
|
|
v_usec = pps_tf[1] - pps_tf[0];
|
|
}
|
|
}
|
|
if (v_usec > MAXTIME)
|
|
pps_jitcnt++;
|
|
v_usec = (v_usec << PPS_AVG) - pps_jitter;
|
|
if (v_usec < 0)
|
|
pps_jitter -= -v_usec >> PPS_AVG;
|
|
else
|
|
pps_jitter += v_usec >> PPS_AVG;
|
|
if (pps_jitter > (MAXTIME >> 1))
|
|
time_status |= STA_PPSJITTER;
|
|
|
|
/*
|
|
* During the calibration interval adjust the starting time when
|
|
* the tick overflows. At the end of the interval compute the
|
|
* duration of the interval and the difference of the hardware
|
|
* counters at the beginning and end of the interval. This code
|
|
* is deliciously complicated by the fact valid differences may
|
|
* exceed the value of tick when using long calibration
|
|
* intervals and small ticks. Note that the counter can be
|
|
* greater than tick if caught at just the wrong instant, but
|
|
* the values returned and used here are correct.
|
|
*/
|
|
bigtick = (long)tick << SHIFT_USEC;
|
|
pps_usec -= pps_freq;
|
|
if (pps_usec >= bigtick)
|
|
pps_usec -= bigtick;
|
|
if (pps_usec < 0)
|
|
pps_usec += bigtick;
|
|
pps_time.tv_sec++;
|
|
pps_count++;
|
|
if (pps_count < (1 << pps_shift))
|
|
return;
|
|
pps_count = 0;
|
|
pps_calcnt++;
|
|
u_usec = usec << SHIFT_USEC;
|
|
v_usec = pps_usec - u_usec;
|
|
if (v_usec >= bigtick >> 1)
|
|
v_usec -= bigtick;
|
|
if (v_usec < -(bigtick >> 1))
|
|
v_usec += bigtick;
|
|
if (v_usec < 0)
|
|
v_usec = -(-v_usec >> pps_shift);
|
|
else
|
|
v_usec = v_usec >> pps_shift;
|
|
pps_usec = u_usec;
|
|
cal_sec = tvp->tv_sec;
|
|
cal_usec = tvp->tv_usec;
|
|
cal_sec -= pps_time.tv_sec;
|
|
cal_usec -= pps_time.tv_usec;
|
|
if (cal_usec < 0) {
|
|
cal_usec += 1000000;
|
|
cal_sec--;
|
|
}
|
|
pps_time = *tvp;
|
|
|
|
/*
|
|
* Check for lost interrupts, noise, excessive jitter and
|
|
* excessive frequency error. The number of timer ticks during
|
|
* the interval may vary +-1 tick. Add to this a margin of one
|
|
* tick for the PPS signal jitter and maximum frequency
|
|
* deviation. If the limits are exceeded, the calibration
|
|
* interval is reset to the minimum and we start over.
|
|
*/
|
|
u_usec = (long)tick << 1;
|
|
if (!((cal_sec == -1 && cal_usec > (1000000 - u_usec))
|
|
|| (cal_sec == 0 && cal_usec < u_usec))
|
|
|| v_usec > time_tolerance || v_usec < -time_tolerance) {
|
|
pps_errcnt++;
|
|
pps_shift = PPS_SHIFT;
|
|
pps_intcnt = 0;
|
|
time_status |= STA_PPSERROR;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* A three-stage median filter is used to help deglitch the pps
|
|
* frequency. The median sample becomes the frequency offset
|
|
* estimate; the difference between the other two samples
|
|
* becomes the frequency dispersion (stability) estimate.
|
|
*/
|
|
pps_ff[2] = pps_ff[1];
|
|
pps_ff[1] = pps_ff[0];
|
|
pps_ff[0] = v_usec;
|
|
if (pps_ff[0] > pps_ff[1]) {
|
|
if (pps_ff[1] > pps_ff[2]) {
|
|
u_usec = pps_ff[1]; /* 0 1 2 */
|
|
v_usec = pps_ff[0] - pps_ff[2];
|
|
} else if (pps_ff[2] > pps_ff[0]) {
|
|
u_usec = pps_ff[0]; /* 2 0 1 */
|
|
v_usec = pps_ff[2] - pps_ff[1];
|
|
} else {
|
|
u_usec = pps_ff[2]; /* 0 2 1 */
|
|
v_usec = pps_ff[0] - pps_ff[1];
|
|
}
|
|
} else {
|
|
if (pps_ff[1] < pps_ff[2]) {
|
|
u_usec = pps_ff[1]; /* 2 1 0 */
|
|
v_usec = pps_ff[2] - pps_ff[0];
|
|
} else if (pps_ff[2] < pps_ff[0]) {
|
|
u_usec = pps_ff[0]; /* 1 0 2 */
|
|
v_usec = pps_ff[1] - pps_ff[2];
|
|
} else {
|
|
u_usec = pps_ff[2]; /* 1 2 0 */
|
|
v_usec = pps_ff[1] - pps_ff[0];
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Here the frequency dispersion (stability) is updated. If it
|
|
* is less than one-fourth the maximum (MAXFREQ), the frequency
|
|
* offset is updated as well, but clamped to the tolerance. It
|
|
* will be processed later by the hardclock() routine.
|
|
*/
|
|
v_usec = (v_usec >> 1) - pps_stabil;
|
|
if (v_usec < 0)
|
|
pps_stabil -= -v_usec >> PPS_AVG;
|
|
else
|
|
pps_stabil += v_usec >> PPS_AVG;
|
|
if (pps_stabil > MAXFREQ >> 2) {
|
|
pps_stbcnt++;
|
|
time_status |= STA_PPSWANDER;
|
|
return;
|
|
}
|
|
if (time_status & STA_PPSFREQ) {
|
|
if (u_usec < 0) {
|
|
pps_freq -= -u_usec >> PPS_AVG;
|
|
if (pps_freq < -time_tolerance)
|
|
pps_freq = -time_tolerance;
|
|
u_usec = -u_usec;
|
|
} else {
|
|
pps_freq += u_usec >> PPS_AVG;
|
|
if (pps_freq > time_tolerance)
|
|
pps_freq = time_tolerance;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Here the calibration interval is adjusted. If the maximum
|
|
* time difference is greater than tick / 4, reduce the interval
|
|
* by half. If this is not the case for four consecutive
|
|
* intervals, double the interval.
|
|
*/
|
|
if (u_usec << pps_shift > bigtick >> 2) {
|
|
pps_intcnt = 0;
|
|
if (pps_shift > PPS_SHIFT)
|
|
pps_shift--;
|
|
} else if (pps_intcnt >= 4) {
|
|
pps_intcnt = 0;
|
|
if (pps_shift < PPS_SHIFTMAX)
|
|
pps_shift++;
|
|
} else
|
|
pps_intcnt++;
|
|
}
|
|
#endif /* PPS_SYNC */
|
|
#endif /* NTP */
|
|
|
|
/*
|
|
* Return information about system clocks.
|
|
*/
|
|
int
|
|
sysctl_clockrate(void *where, size_t *sizep)
|
|
{
|
|
struct clockinfo clkinfo;
|
|
|
|
/*
|
|
* Construct clockinfo structure.
|
|
*/
|
|
clkinfo.tick = tick;
|
|
clkinfo.tickadj = tickadj;
|
|
clkinfo.hz = hz;
|
|
clkinfo.profhz = profhz;
|
|
clkinfo.stathz = stathz ? stathz : hz;
|
|
return (sysctl_rdstruct(where, sizep, NULL, &clkinfo, sizeof(clkinfo)));
|
|
}
|