Copyright (c) 2001 The NetBSD Foundation, Inc.
All rights reserved.
This code is derived from software contributed to The NetBSD Foundation
by Thomas Klausner.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
.Dd March 25, 2010 .Dt HARDCLOCK 9 .Os .Sh NAME .Nm hardclock .Nd real-time timer .Sh SYNOPSIS .Ft void .Fn hardclock "struct clockframe *frame" .Sh DESCRIPTION The .Fn hardclock function is called .Xr hz 9 times per second. It implements the real-time system clock. The argument .Va frame is an opaque, machine-dependent structure that encapsulates the previous machine state.
p The .Fn hardclock performs different tasks such as: l -bullet -offset indent t Run the current process's virtual and profile time (decrease the corresponding timers, if they are activated, and generate .Li SIGVTALRM or .Li SIGPROF , respectively). t Increment the time-of-day, taking care of any .Xr ntpd 8 or .Xr adjtime 2 induced changes and leap seconds, as well as any necessary compensations to keep in sync with PPS signals or external clocks, if support for this is in the kernel (see .Xr options 4 ) . t Schedule softclock interrupts if any callouts should be triggered (see .Xr callout 9 ) . .El .Sh SEE ALSO .Xr adjtime 2 , .Xr ntp_adjtime 2 , .Xr signal 7 , .Xr ntpd 8 , .Xr callout 9 , .Xr hz 9
Indexes created Tue Sep 23 02:09:52 GMT 2025