Re: Performance drop on kernel-4.17 visible on Stream, Linpack and NAS parallel benchmarks

From: Rafael J. Wysocki
Date: Wed Jun 06 2018 - 08:56:26 EST


On Wed, Jun 6, 2018 at 2:50 PM, Jakub Racek <jracek@xxxxxxxxxx> wrote:
> +++ Rafael J. Wysocki [06/06/18 14:34 +0200]:
>>
>> On Wed, Jun 6, 2018 at 2:27 PM, Jakub Racek <jracek@xxxxxxxxxx> wrote:
>>>
>>> Hi,
>>>
>>> There is a huge performance regression on the 2 and 4 NUMA node systems
>>> on
>>> stream benchmark with 4.17 kernel compared to 4.16 kernel. Stream,
>>> Linpack
>>> and NAS parallel benchmarks show upto 50% performance drop.
>>
>>
>> OK, and why do you think that it is related to ACPI?
>
>
> I don't know where the problems is or who to CC.
> What information should be added? I can probably provide it, if I know
> what.

The problem appears to be reproducible 100% of the time, so can you
possibly carry out a "git bisect" binary search to find the
problematic commit?

Thanks,
Rafael