Re: [x86/copy_mc] a0ac629ebe: fio.read_iops -43.3% regression

[Ingo Molnar]

* kernel test robot <rong.a.chen@xxxxxxxxx> wrote:

> Greeting,
> 
> FYI, we noticed a -43.3% regression of fio.read_iops due to commit:
> 
> 
> commit: a0ac629ebe7b3d248cb93807782a00d9142fdb98 ("x86/copy_mc: Introduce copy_mc_generic()")
> url: https://github.com/0day-ci/linux/commits/Dan-Williams/Renovate-memcpy_mcsafe-with-copy_mc_to_-user-kernel/20200802-014046
> 
> 
> in testcase: fio-basic
> on test machine: 96 threads Intel(R) Xeon(R) Gold 6252 CPU @ 2.10GHz with 256G memory
> with following parameters:

So this performance regression, if it isn't a spurious result, looks 
concerning. Is this expected?

Thanks,

	Ingo