[PATCH] D53927: [AArch64] Enable libm vectorized functions via SLEEF

[Stefan Teleman via Phabricator via llvm-commits]

steleman added a comment.



> 1. @steleman I don't understand some of the values in your benchmarks. In particular, sin and cos should have similar timings, not differ so much as in your report. I wonder whether the choice of the CLOCK_PROCESS_CPUTIME_ID might have caused this. I think that CLOCK_PROCESS_CPUTIME_ID might translate in a syscall, and therefore cause much overhead in the measurement. I'd rather use CLOCK_MONOTONIC. Also, to make sure you are just measuring the function latency, I think you should invoke the benchmark on array of smaller size, and invoke the call a couple of times before actually starting the time measurement, to reduce the amount of noise causes by warm up effects.

I don't understand this. Are you suggesting that decreasing the size of the statistical sample increases the accuracy?

At any rate, the test benchmark and the results spreadsheet aren't part of this changeset.

So I'm confused as to what's being asked here.


https://reviews.llvm.org/D53927