Quoting r. Roland Dreier <[EMAIL PROTECTED]>: > Subject: Re: ANNOUNCE: First usable version of userspace verbs > > mst> but I also changed the clock sampling to use the realtime > mst> clock from -lrt, since it gives a more consistent timing > mst> results on my system. > > By the way, what exactly are you using? clock_gettime() with > CLOCK_REALTIME? Do you know what the difference from gettimeofday is? > > I haven't followed Linux timekeeping development too closely but there > should be some portable libc way to get high-resolution time without a > system call (ie rdtsc on x86, mftb on ppc, etc). > > - R. >
Looking at libc sources (glibc-2.3.2-200304020432) there appears an internal macro for it, but I dont see it exported, it seems to be used for ./malloc/memusage.c implementation. I'll look for a library outside of libc that we can use. clock_gettime is a syscall, so has overhead course. Still, since we call it once per 1000 iterations, the overhead isnt big. -- MST - Michael S. Tsirkin _______________________________________________ openib-general mailing list [email protected] http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
