Some tips for benchmarking

George Rimar via llvm-commits llvm-commits at
Thu Oct 20 00:42:34 PDT 2016

>After much pain I decided that instead of just running tests many
>times I should put some effort in figuring out why perf numbers were
>so hard to reproduce on my machine.
>I was already disabling address space randomization and setting the
>scaling_governor to performance. Other things I found
>* Use to reserve a cpu for just
>the program you are benchmarking.
>* Disable the SMP pair (echo 0 > /sys/devices/system/cpu/cpuX/online)
>of the cpu you will use for the benchmark.
>* disable turbo mode (echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo).
>The results are pretty awesome:
>3.012355647 seconds time elapsed         ( +-  0.01% )

That might be helpful, thanks for sharing !


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