lightweight function for measuring time ( better than clock_getime )

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Operating Systems Linux Red Hat lightweight function for measuring time ( better than clock_getime )
# 1  
Old 07-17-2011
lightweight function for measuring time ( better than clock_getime )

I have a Red Hat Enterprise with Real Time kernel.

Are you aware if there are C functions for this kernel or some code/library for this OS for measuring time more lightweight than clock_gettime and gettimeofday? THe hardware I have is NUMA.

Reading forums I found gethrtime but it is available on Solaris only; this last spends few cycles compared to clock_gettime and gettimeofday eating the CPU.

Do you know if for Red Hat someomene did something similar?
My distro is the following

THanks a lot

     uname -a
     Linux lndbxdev01 #1 SMP PREEMPT RT 
     Mon Mar 23 10:58:10 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux

     Red Hat Enterprise Linux Server release 5.3 (Tikanga)

# 2  
Old 07-19-2011
after few research I didn't find a better function than clock_getime or a specific function for RedHat distro BUT I can tell you that in the 2.6 kernel there are new ID available for clock_getime.
If you use version 2.6.28 you can use a new clock type, CLOCK_MONOTONIC_RAW
If you use version 2.6.32 you can use a new clock type, CLOCK_REALTIME_COARSE and CLOCK_MONOTIC_COARSE.

Someone did some tests with it and they seem 5 times faster than the code used by CLOCK_MONOTONIC and CLOCK_REALTIME.

Best Regards
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