Messages in this thread | | | Subject | Re: 2.6.15:kernel/time.c: The Nanosecond and code duplication | From | Andi Kleen <> | Date | 13 Feb 2006 11:12:32 +0100 |
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"Ulrich Windl" <ulrich.windl@rz.uni-regensburg.de> writes:
> but there's no POSIX like syscall interface > (clock_getres, clock_gettime, clock_settime) yet.
% grep clock include/asm-x86_64/unistd.h #define __NR_clock_settime 227 __SYSCALL(__NR_clock_settime, sys_clock_settime) #define __NR_clock_gettime 228 __SYSCALL(__NR_clock_gettime, sys_clock_gettime) #define __NR_clock_getres 229 __SYSCALL(__NR_clock_getres, sys_clock_getres) #define __NR_clock_nanosleep 230 __SYSCALL(__NR_clock_nanosleep, sys_clock_nanosleep)
Has been available for quite some time.
However the calls are currently slower than gettimeofday and also don't use nanoseconds internally in all cases (depends on the architecture), but still microseconds. But I'm not sure it matters that much because the underlying timers are often not better than microseconds anyways and with nanoseconds you start to time even the inherent system call latency.
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