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| author | H.J. Lu <hjl.tools@gmail.com> | 2020-06-05 09:48:04 -0700 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2020-06-05 09:48:07 -0700 |
| commit | e52434a2e4d1105272daaef87678da950fbec73f (patch) | |
| tree | 32d8bfaeedb32a24a51a5ee588f0417542b69f29 /benchtests/README | |
| parent | f6070476687af9ca1b5837f8a45047acdd419b08 (diff) | |
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benchtests: Restore the clock_gettime option
commit 7621e38bf3c58b2d0359545f1f2898017fd89d05
Author: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
Date: Tue Jan 29 17:43:45 2019 +0000
Add generic hp-timing support
removed the clock_gettime option. Restore the clock_gettime option for
some x86 CPUs on which value from RDTSC may not be incremented at a fixed
rate.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Diffstat (limited to 'benchtests/README')
| -rw-r--r-- | benchtests/README | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/benchtests/README b/benchtests/README index c4f03fd872..f440f3295a 100644 --- a/benchtests/README +++ b/benchtests/README @@ -27,7 +27,12 @@ BENCH_DURATION. The benchmark suite does function call measurements using architecture-specific high precision timing instructions whenever available. When such support is -not available, it uses clock_gettime (CLOCK_MONOTONIC). +not available, it uses clock_gettime (CLOCK_MONOTONIC). One can force the +benchmark to use clock_gettime by invoking make as follows: + + $ make USE_CLOCK_GETTIME=1 bench + +Again, one must run `make bench-clean' before changing the measurement method. On x86 processors, RDTSCP instruction provides more precise timing data than RDTSC instruction. All x86 processors since 2010 support RDTSCP |