Some tips for benchmarking
Rafael Espíndola via llvm-commits
llvm-commits at lists.llvm.org
Wed Oct 19 19:39:39 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 https://github.com/lpechacek/cpuset 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% )
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