306 lines
9.4 KiB
C
306 lines
9.4 KiB
C
/* $NetBSD: kern_cctr.c,v 1.10 2019/06/24 06:24:33 skrll Exp $ */
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/*-
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* Copyright (c) 2006, 2008 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* re-implementation of TSC for MP systems merging cc_microtime and
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* TSC for timecounters by Frank Kardel
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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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*
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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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/* basic calibration ideas are (kern_microtime.c): */
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/******************************************************************************
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* *
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* Copyright (c) David L. Mills 1993, 1994 *
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* *
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* Permission to use, copy, modify, and distribute this software and its *
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* documentation for any purpose and without fee is hereby granted, provided *
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* that the above copyright notice appears in all copies and that both the *
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* copyright notice and this permission notice appear in supporting *
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* documentation, and that the name University of Delaware not be used in *
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* advertising or publicity pertaining to distribution of the software *
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* without specific, written prior permission. The University of Delaware *
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* makes no representations about the suitability this software for any *
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* purpose. It is provided "as is" without express or implied warranty. *
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* *
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******************************************************************************/
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/* reminiscents from older version of this file are: */
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/*-
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* Copyright (c) 1998-2003 Poul-Henning Kamp
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* All rights reserved.
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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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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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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#include <sys/cdefs.h>
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/* __FBSDID("$FreeBSD: src/sys/i386/i386/tsc.c,v 1.204 2003/10/21 18:28:34 silby Exp $"); */
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__KERNEL_RCSID(0, "$NetBSD: kern_cctr.c,v 1.10 2019/06/24 06:24:33 skrll Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/sysctl.h>
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#include <sys/time.h>
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#include <sys/timetc.h>
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#include <sys/kernel.h>
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#include <sys/power.h>
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#include <sys/cpu.h>
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#include <machine/cpu_counter.h>
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/* XXX make cc_timecounter.tc_frequency settable by sysctl() */
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static timecounter_pps_t cc_calibrate;
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void cc_calibrate_cpu(struct cpu_info *);
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static int64_t cc_cal_val; /* last calibrate time stamp */
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static struct timecounter cc_timecounter = {
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.tc_get_timecount = cc_get_timecount,
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.tc_poll_pps = cc_calibrate,
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.tc_counter_mask = ~0u,
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.tc_frequency = 0,
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.tc_name = "unknown cycle counter",
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/*
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* don't pick cycle counter automatically
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* if frequency changes might affect cycle counter
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*/
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.tc_quality = -100000,
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.tc_priv = NULL,
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.tc_next = NULL
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};
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/*
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* initialize cycle counter based timecounter
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*/
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struct timecounter *
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cc_init(timecounter_get_t getcc, uint64_t freq, const char *name, int quality)
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{
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if (getcc != NULL)
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cc_timecounter.tc_get_timecount = getcc;
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cc_timecounter.tc_frequency = freq;
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cc_timecounter.tc_name = name;
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cc_timecounter.tc_quality = quality;
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tc_init(&cc_timecounter);
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return &cc_timecounter;
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}
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/*
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* pick up tick count scaled to reference tick count
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*/
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u_int
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cc_get_timecount(struct timecounter *tc)
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{
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struct cpu_info *ci;
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int64_t rcc, cc, ncsw;
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u_int gen;
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retry:
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ncsw = curlwp->l_ncsw;
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__insn_barrier();
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ci = curcpu();
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if (ci->ci_cc.cc_denom == 0) {
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/*
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* This is our first time here on this CPU. Just
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* start with reasonable initial values.
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*/
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ci->ci_cc.cc_cc = cpu_counter32();
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ci->ci_cc.cc_val = 0;
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if (ci->ci_cc.cc_gen == 0)
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ci->ci_cc.cc_gen++;
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ci->ci_cc.cc_denom = cpu_frequency(ci);
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if (ci->ci_cc.cc_denom == 0)
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ci->ci_cc.cc_denom = cc_timecounter.tc_frequency;
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ci->ci_cc.cc_delta = ci->ci_cc.cc_denom;
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}
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/*
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* read counter and re-read when the re-calibration
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* strikes inbetween
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*/
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do {
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/* pick up current generation number */
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gen = ci->ci_cc.cc_gen;
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/* determine local delta ticks */
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cc = cpu_counter32() - ci->ci_cc.cc_cc;
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if (cc < 0)
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cc += 0x100000000LL;
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/* scale to primary */
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rcc = (cc * ci->ci_cc.cc_delta) / ci->ci_cc.cc_denom
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+ ci->ci_cc.cc_val;
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} while (gen == 0 || gen != ci->ci_cc.cc_gen);
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__insn_barrier();
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if (ncsw != curlwp->l_ncsw) {
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/* Was preempted */
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goto retry;
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}
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return rcc;
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}
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/*
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* called once per clock tick via the pps callback
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* for the calibration of the TSC counters.
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* it is called only for the PRIMARY cpu. all
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* other cpus are called via a broadcast IPI
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* calibration interval is 1 second - we call
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* the calibration code only every hz calls
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*/
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static void
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cc_calibrate(struct timecounter *tc)
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{
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static int calls;
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struct cpu_info *ci;
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KASSERT(kpreempt_disabled());
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/*
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* XXX: for high interrupt frequency
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* support: ++calls < hz / tc_tick
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*/
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if (++calls < hz)
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return;
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calls = 0;
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ci = curcpu();
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/* pick up reference ticks */
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cc_cal_val = cpu_counter32();
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#if defined(MULTIPROCESSOR)
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cc_calibrate_mp(ci);
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#endif
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cc_calibrate_cpu(ci);
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}
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/*
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* This routine is called about once per second directly by the master
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* processor and via an interprocessor interrupt for other processors.
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* It determines the CC frequency of each processor relative to the
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* master clock and the time this determination is made. These values
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* are used by cc_get_timecount() to interpolate the ticks between
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* timer interrupts. Note that we assume the kernel variables have
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* been zeroed early in life.
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*/
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void
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cc_calibrate_cpu(struct cpu_info *ci)
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{
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u_int gen;
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int64_t val;
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int64_t delta, denom;
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int s;
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#ifdef TIMECOUNTER_DEBUG
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int64_t factor, old_factor;
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#endif
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val = cc_cal_val;
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s = splhigh();
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/* create next generation number */
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gen = ci->ci_cc.cc_gen;
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gen++;
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if (gen == 0)
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gen++;
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/* update in progress */
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ci->ci_cc.cc_gen = 0;
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denom = ci->ci_cc.cc_cc;
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ci->ci_cc.cc_cc = cpu_counter32();
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if (ci->ci_cc.cc_denom == 0) {
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/*
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* This is our first time here on this CPU. Just
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* start with reasonable initial values.
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*/
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ci->ci_cc.cc_val = val;
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ci->ci_cc.cc_denom = cpu_frequency(ci);
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if (ci->ci_cc.cc_denom == 0)
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ci->ci_cc.cc_denom = cc_timecounter.tc_frequency;
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ci->ci_cc.cc_delta = ci->ci_cc.cc_denom;
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ci->ci_cc.cc_gen = gen;
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splx(s);
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return;
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}
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#ifdef TIMECOUNTER_DEBUG
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old_factor = (ci->ci_cc.cc_delta * 1000 ) / ci->ci_cc.cc_denom;
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#endif
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/* local ticks per period */
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denom = ci->ci_cc.cc_cc - denom;
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if (denom < 0)
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denom += 0x100000000LL;
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ci->ci_cc.cc_denom = denom;
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/* reference ticks per period */
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delta = val - ci->ci_cc.cc_val;
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if (delta < 0)
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delta += 0x100000000LL;
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ci->ci_cc.cc_val = val;
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ci->ci_cc.cc_delta = delta;
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/* publish new generation number */
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ci->ci_cc.cc_gen = gen;
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splx(s);
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#ifdef TIMECOUNTER_DEBUG
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factor = (delta * 1000) / denom - old_factor;
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if (factor < 0)
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factor = -factor;
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if (factor > old_factor / 10)
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printf("cc_calibrate_cpu[%u]: 10%% exceeded - delta %"
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PRId64 ", denom %" PRId64 ", factor %" PRId64
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", old factor %" PRId64"\n", ci->ci_index,
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delta, denom, (delta * 1000) / denom, old_factor);
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#endif /* TIMECOUNTER_DEBUG */
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}
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