Re: [RFC][PATCH 13/16] sched: Add core wide task selection and scheduling.

Subhra Mazumdar
2019-04-19T23:20:35Z

On 4/19/19 1:40 AM, Ingo Molnar wrote:
> * Subhra Mazumdar <subhra.mazumdar@oracle.com> wrote:
>
>> I see similar improvement with this patch as removing the condition I
>> earlier mentioned. So that's not needed. I also included the patch for the
>> priority fix. For 2 DB instances, HT disabling stands at -22% for 32 users
>> (from earlier emails).
>>
>>
>> 1 DB instance
>>
>> users  baseline   %idle    core_sched %idle
>> 16     1          84       -4.9% 84
>> 24     1          76       -6.7% 75
>> 32     1          69       -2.4% 69
>>
>> 2 DB instance
>>
>> users  baseline   %idle    core_sched %idle
>> 16     1          66       -19.5% 69
>> 24     1          54       -9.8% 57
>> 32     1          42       -27.2%        48
> So HT disabling slows down the 2DB instance by -22%, while core-sched
> slows it down by -27.2%?
>
> Would it be possible to see all the results in two larger tables (1 DB
> instance and 2 DB instance) so that we can compare the performance of the
> 3 kernel variants with each other:
>
> - "vanilla +HT": Hyperthreading enabled, vanilla scheduler
> - "vanilla -HT": Hyperthreading disabled, vanilla scheduler
> - "core_sched": Hyperthreading enabled, core-scheduling enabled
>
> ?
>
> Thanks,
>
> Ingo
Following are the numbers. Disabling HT gives improvement in some cases.

1 DB instance

users  vanilla+HT   core_sched vanilla-HT
16     1            -4.9% -11.7%
24     1            -6.7% +13.7%
32     1            -2.4% +8%

2 DB instance

users  vanilla+HT   core_sched vanilla-HT
16     1            -19.5% +5.6%
24     1            -9.8% +3.5%
32     1            -27.2%        -22.8%