81 lines
2.9 KiB
Groff
81 lines
2.9 KiB
Groff
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.\" $NetBSD: hardclock.9,v 1.1 2001/09/09 03:07:10 wiz Exp $
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.\"
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.\" Copyright (c) 2001 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 Thomas Klausner.
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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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.Dd September 5, 2001
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.Dt HARDCLOCK 9
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.Os
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.Sh NAME
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.Nm hardclock
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.Nd real-time timer
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.Sh SYNOPSIS
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.Ft void
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.Fn hardclock "struct clockframe *"
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.Sh DESCRIPTION
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The
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.Fn hardclock
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function gets called
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.Xr hz 9
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times per second.
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It performs different tasks:
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.Bl -bullet -compact
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.It
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Run the current process's virtual and profile time (decrease the
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corresponding timers, if they are activated, and generate
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.Li SIGVTALRM
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or
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.Li SIGPROF ,
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respectively).
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.It
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Increment the time-of-day, taking care of any
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.Xr ntpd 8
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or
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.Xr adjtime 2
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induced changes and leap seconds, as well as any necessary
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compensations to keep in sync with PPS signals or external clocks, if
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support for this is in the kernel (see
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.Xr options 4 ) .
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.It
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Schedule softclock interrupts if any callouts should be triggered (see
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.Xr callout 9 ) .
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.El
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.Sh SEE ALSO
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.Xr adjtime 2 ,
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.Xr ntp_adjtime 2 ,
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.Xr signal 7 ,
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.Xr ntpd 8 ,
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.Xr callout 9 ,
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.Xr hz 9
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