diff options
Diffstat (limited to 'static/openbsd/man9/microtime.9')
| -rw-r--r-- | static/openbsd/man9/microtime.9 | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/static/openbsd/man9/microtime.9 b/static/openbsd/man9/microtime.9 new file mode 100644 index 00000000..b2b0eb40 --- /dev/null +++ b/static/openbsd/man9/microtime.9 @@ -0,0 +1,219 @@ +.\" $OpenBSD: microtime.9,v 1.23 2022/12/28 15:46:39 cheloha Exp $ +.\" $NetBSD: microtime.9,v 1.2 1999/03/16 00:40:47 garbled Exp $ +.\" +.\" Copyright (c) 1998 The NetBSD Foundation, Inc. +.\" All rights reserved. +.\" +.\" This code is derived from software contributed to The NetBSD Foundation +.\" by Jeremy Cooper. +.\" +.\" 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 $Mdocdate: December 28 2022 $ +.Dt MICROTIME 9 +.Os +.Sh NAME +.Nm microuptime , +.Nm getmicrouptime , +.Nm nanouptime , +.Nm getnanouptime , +.Nm nsecuptime , +.Nm getnsecuptime , +.Nm getuptime , +.Nm nanoruntime , +.Nm getnsecruntime , +.Nm microtime , +.Nm getmicrotime , +.Nm nanotime , +.Nm getnanotime , +.Nm gettime , +.Nm microboottime , +.Nm nanoboottime +.Nd get the time +.Sh SYNOPSIS +.In sys/time.h +.Ft void +.Fo microuptime +.Fa "struct timeval *tv" +.Fc +.Ft void +.Fo getmicrouptime +.Fa "struct timeval *tv" +.Fc +.Ft void +.Fo nanouptime +.Fa "struct timespec *ts" +.Fc +.Ft void +.Fo getnanouptime +.Fa "struct timespec *ts" +.Fc +.Ft uint64_t +.Fo nsecuptime +.Fa "void" +.Fc +.Ft uint64_t +.Fo getnsecuptime +.Fa "void" +.Fc +.Ft time_t +.Fo getuptime +.Fa "void" +.Fc +.Ft void +.Fo nanoruntime +.Fa "struct timespec *ts" +.Fc +.Ft uint64_t +.Fo getnsecruntime +.Fa "void" +.Fc +.Ft void +.Fo microtime +.Fa "struct timeval *tv" +.Fc +.Ft void +.Fo getmicrotime +.Fa "struct timeval *tv" +.Fc +.Ft void +.Fo nanotime +.Fa "struct timespec *ts" +.Fc +.Ft void +.Fo getnanotime +.Fa "struct timespec *ts" +.Fc +.Ft time_t +.Fo gettime +.Fa "void" +.Fc +.Ft void +.Fo microboottime +.Fa "struct timeval *tv" +.Fc +.Ft void +.Fo nanoboottime +.Fa "struct timespec *ts" +.Fc +.Sh DESCRIPTION +The kernel has three clocks and a variety of interfaces for reading them. +.Pp +The +.Sy uptime +clock measures the time elapsed since the system booted. +It begins at zero and advances monotonically. +The uptime clock may be read with the following functions: +.Bl -column "getmicrouptimeX" "Output Format" "Source" -offset indent +.It Em Name Ta Em Output Format Ta Em Source +.It Fn microuptime Ta Vt struct timeval Ta hardware +.It Fn getmicrouptime Ta Vt struct timeval Ta timestamp +.It Fn nanouptime Ta Vt struct timespec Ta hardware +.It Fn getnanouptime Ta Vt struct timespec Ta timestamp +.It Fn nsecuptime Ta Ft uint64_t Ta hardware +.It Fn getnsecuptime Ta Ft uint64_t Ta timestamp +.It Fn getuptime Ta Ft time_t Ta timestamp +.El +.Pp +The +.Sy runtime +clock measures the time elapsed since the system booted, +less any time the system is suspended or hibernating. +It begins at zero and normally advances monotonically, +but pauses while the system is suspended or hibernating. +The runtime clock may be read with the following functions: +.Bl -column "getnsecruntimeX" "Output Format" "Source" -offset indent +.It Em Name Ta Em Output Format Ta Em Source +.It Fn nanoruntime Ta Vt struct timespec Ta hardware +.It Fn getnsecruntime Ta Ft uint64_t Ta timestamp +.El +.Pp +The +.Sy UTC +clock measures the time elapsed since Jan 1 1970 00:00:00 +.Pq the Unix Epoch . +The clock normally advances monotonically, +but jumps when a process calls +.Xr clock_settime 2 +or +.Xr settimeofday 2 . +The UTC clock may be read with the following functions: +.Bl -column "getmicrotimeX" "Output Format" "Source" -offset indent +.It Em Name Ta Em Output Format Ta Em Source +.It Fn microtime Ta Vt struct timeval Ta hardware +.It Fn getmicrotime Ta Vt struct timeval Ta timestamp +.It Fn nanotime Ta Vt struct timespec Ta hardware +.It Fn getnanotime Ta Vt struct timespec Ta timestamp +.It Fn gettime Ta Ft time_t Ta timestamp +.El +.Pp +The kernel also maintains a +.Sy boot timestamp . +It is the moment on the UTC clock when the system booted. +The timestamp jumps when a process calls +.Xr clock_settime 2 +or +.Xr settimeofday 2 . +The boot timestamp may be read with the following functions: +.Bl -column "microboottimeX" "Output Format" "Source" -offset indent +.It Em Name Ta Em Output Format Ta Em Source +.It Fn microboottime Ta Vt struct timeval Ta timestamp +.It Fn nanoboottime Ta Vt struct timespec Ta timestamp +.El +.Pp +Functions that source from the +.Em hardware +provide the most precise result possible. +Functions that source from a +.Em timestamp +provide a far less precise result, +but do so very quickly. +On most platforms, +timestamps are updated approximately 100 times per second. +.Sh CONTEXT +These functions may be called during autoconf, +from process context, +or from any interrupt context. +.Sh RETURN VALUES +.Fn nsecuptime , +.Fn getnsecuptime , +and +.Fn getnsecruntime +return a count of nanoseconds. +.Pp +.Fn getuptime +and +.Fn gettime +return a count of seconds. +.Sh ERRORS +These functions are always successful, +and no return value is reserved to indicate an error. +.Sh CODE REFERENCES +.Pa sys/kern/kern_tc.c +.Sh SEE ALSO +.Xr clock_settime 2 , +.Xr settimeofday 2 , +.Xr timeradd 3 , +.Xr hardclock 9 , +.Xr hz 9 , +.Xr inittodr 9 , +.Xr tc_init 9 |