RE: Need help with accurate timers for multithreaded programs on Linux/X-86

There are several POSIX timer_* API in nptl such as timer_create(),
timer_gettime(), etc. nptl/sysdeps/pthread/tst-timer.c shows how to use
them. 

Another one is http://sourceforge.net/projects/high-res-timers.


> 
> Hi Folks,
>   I will appreciate if people can point me to accurate and reliable
> timers for multithreaded programs on Linux/X-86 (specifically RH9.0).
> 
> I have quite a bit of multithreading experience (mainly on Solaris)
> but very little on Linux.  On Solaris, the two timers: gethrvtime()
> and gethrtime() are proving to be very valuable in tuning/testing
> the code that I am currently multithreading.
> 
> On Linux, I have tried both gettimeofday based timer and a timer
> using RDTSC instruction in IA-32 but am not able to get repeatable
> and reliable timings with these...well bottomline is that we are
> seeing reasonable scaling (eg. 1.6-1.7X on 2-way) on Solaris (version
> 8)
> but basically none on Linux (RH 9.0).  I suspect my lack of
> experience on Linux is probably the reason...hence request for
> help from you all.
> 
> I know this is a very general question but any pointers you all
> can provide on how to accurately measure time in portions of
> code (on a per-thread basis) and/or if I should try a different
> version of Linux thread library will be really appreciated.
> 
> regards,
> 
> --Rajat