glibc/sysdeps/posix/clock_getres.c
Roland McGrath 2f4f3bd4a9 2005-04-27 Roland McGrath <roland@redhat.com>
* sysdeps/unix/sysv/linux/kernel-posix-cpu-timers.h: New file.
	* sysdeps/unix/sysv/linux/clock_getcpuclockid.c: New file.
	* sysdeps/unix/sysv/linux/ia64/clock_getcpuclockid.c
	(HAS_CPUCLOCK): New macro.
	(clock_getcpuclockid): Function removed.
	#include the new linux file to define it instead.
	* sysdeps/unix/clock_gettime.c [HP_TIMING_AVAIL] (hp_timing_gettime):
	New function, broken out of ...
	(clock_gettime) [HP_TIMING_AVAIL]: ... here.  Call it.
	(realtime_gettime): New function, broken out of ...
	(clock_gettime) [! HANDLED_REALTIME]: ... here.  Call it.
	(clock_gettime) [SYSDEP_GETTIME_CPU]: Use new macro in default case.
	* sysdeps/unix/sysv/linux/clock_gettime.c (SYSCALL_GETTIME): New macro.
	(SYSDEP_GETTIME_CPUTIME): New macro.
	(SYSDEP_GETTIME): Use both.
	[! __ASSUME_POSIX_TIMERS] (maybe_syscall_gettime): New function, broken
	out of ...
	(SYSDEP_GETTIME): ... here.  Use it.
	[__NR_clock_gettime] (HANDLED_CPUTIME): Define it.
	(SYSDEP_GETTIME_CPUTIME): New macro.  Handle CPU timers by trying
	kernel support and falling back to hp-timing code.
	* sysdeps/posix/clock_getres.c
	[HP_TIMING_AVAIL] (hp_timing_getres): New function, broken out of ...
	(clock_getres) [HP_TIMING_AVAIL]: ... here.  Call it.
	(realtime_getres): New function, broken out of ...
	(clock_getres) [! HANDLED_REALTIME]: ... here.  Call it.
	(clock_getres) [SYSDEP_GETRES_CPU]: Use new macro in default case.
	* sysdeps/unix/sysv/linux/clock_getres.c (SYSCALL_GETRES): New macro.
	(SYSDEP_GETRES_CPUTIME): New macro.
	(SYSDEP_GETRES): Use both.
	[! __ASSUME_POSIX_TIMERS] (maybe_syscall_getres): New function, broken
	out of ...
	(SYSDEP_GETRES): ... here.  Use it.
	[__NR_clock_getres] (HANDLED_CPUTIME): Define it.
	(SYSDEP_GETRES_CPUTIME): New macro.  Handle CPU timers by trying
	kernel support and falling back to hp-timing code.
	* sysdeps/unix/sysv/linux/clock_nanosleep.c: Handle
	CLOCK_PROCESS_CPUTIME_ID and CLOCK_PROCESS_THREAD_ID specially,
	translating to the kernel clockid_t for our own process/thread clock.
2005-04-27 08:01:41 +00:00

119 lines
3.0 KiB
C

/* clock_getres -- Get the resolution of a POSIX clockid_t.
Copyright (C) 1999, 2000, 2001, 2003, 2004 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <errno.h>
#include <stdint.h>
#include <time.h>
#include <unistd.h>
#include <sys/param.h>
#include <libc-internal.h>
#if HP_TIMING_AVAIL
static long int nsec; /* Clock frequency of the processor. */
static inline int
hp_timing_getres (struct timespec *res)
{
if (__builtin_expect (nsec == 0, 0))
{
hp_timing_t freq;
/* This can only happen if we haven't initialized the `nsec'
variable yet. Do this now. We don't have to protect this
code against multiple execution since all of them should
lead to the same result. */
freq = __get_clockfreq ();
if (__builtin_expect (freq == 0, 0))
/* Something went wrong. */
return -1;
nsec = MAX (UINT64_C (1000000000) / freq, 1);
}
/* Fill in the values.
The seconds are always zero (unless we have a 1Hz machine). */
res->tv_sec = 0;
res->tv_nsec = nsec;
return 0;
}
#endif
static inline int
realtime_getres (struct timespec *res)
{
long int clk_tck = sysconf (_SC_CLK_TCK);
if (__builtin_expect (clk_tck != -1, 1))
{
/* This implementation assumes that the realtime clock has a
resolution higher than 1 second. This is the case for any
reasonable implementation. */
res->tv_sec = 0;
res->tv_nsec = 1000000000 / clk_tck;
return 0;
}
return -1;
}
/* Get resolution of clock. */
int
clock_getres (clockid_t clock_id, struct timespec *res)
{
int retval = -1;
switch (clock_id)
{
#ifdef SYSDEP_GETRES
SYSDEP_GETRES;
#endif
#ifndef HANDLED_REALTIME
case CLOCK_REALTIME:
retval = realtime_getres (res);
break;
#endif /* handled REALTIME */
default:
#ifdef SYSDEP_GETRES_CPU
SYSDEP_GETRES_CPU;
#endif
#if HP_TIMING_AVAIL
if ((clock_id & ((1 << CLOCK_IDFIELD_SIZE) - 1))
== CLOCK_THREAD_CPUTIME_ID)
retval = hp_timing_getres (res);
else
#endif
__set_errno (EINVAL);
break;
#if HP_TIMING_AVAIL && !defined HANDLED_CPUTIME
case CLOCK_PROCESS_CPUTIME_ID:
case CLOCK_THREAD_CPUTIME_ID:
retval = hp_timing_getres (res);
break;
#endif
}
return retval;
}