Re: hackbench vs select_idle_sibling; was: [tip:sched/core] sched/fair, cpumask: Export for_each_cpu_wrap()

Chris Mason
2017-06-09T17:53:30Z

On 06/06/2017 05:21 AM, Peter Zijlstra wrote:
> On Mon, Jun 05, 2017 at 02:00:21PM +0100, Matt Fleming wrote:
>> On Fri, 19 May, at 04:00:35PM, Matt Fleming wrote:
>>> On Wed, 17 May, at 12:53:50PM, Peter Zijlstra wrote:
>>>>
>>>> Please test..
>>>
>>> Results are still coming in but things do look better with your patch
>>> applied.
>>>
>>> It does look like there's a regression when running hackbench in
>>> process mode and when the CPUs are not fully utilised, e.g. check this
>>> out:
>>
>> This turned out to be a false positive; your patch improves things as
>> far as I can see.
>
> Hooray, I'll move it to a part of the queue intended for merging.

It's a little late, but Roman Gushchin helped get some runs of this with
our production workload. The patch is every so slightly better.

Thanks!

-chris