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From: Aubrey Li <aubrey.li@linux.intel.com>
To: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Mel Gorman <mgorman@techsingularity.net>,
	Rik van Riel <riel@surriel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Valentin Schneider <valentin.schneider@arm.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Gautham R Shenoy <ego@linux.vnet.ibm.com>,
	Parth Shah <parth@linux.ibm.com>
Subject: Re: [PATCH v2 6/8] sched/idle: Move busy_cpu accounting to idle callback
Date: Mon, 17 May 2021 20:48:46 +0800	[thread overview]
Message-ID: <9d493353-7a27-16aa-3e99-c6a07e69de25@linux.intel.com> (raw)
In-Reply-To: <20210517104058.GW2633526@linux.vnet.ibm.com>

On 5/17/21 6:40 PM, Srikar Dronamraju wrote:
> * Aubrey Li <aubrey.li@linux.intel.com> [2021-05-14 12:11:50]:
> 
>> On 5/13/21 3:31 PM, Srikar Dronamraju wrote:
>>> * Aubrey Li <aubrey.li@linux.intel.com> [2021-05-12 16:08:24]:
>>>> On 5/7/21 12:45 AM, Srikar Dronamraju wrote:
> 
> <snip>
> 
>>>> Also, for those frequent context-switching tasks with very short idle,
>>>> it's expensive for scheduler to mark idle/busy every time, that's why
>>>> my patch only marks idle every time and marks busy ratelimited in
>>>> scheduler tick.
>>>>
>>>
>>> I have tried few tasks with very short idle times and updating nr_busy
>>> everytime, doesnt seem to be impacting. Infact, it seems to help in picking
>>> the idler-llc more often.
>>>
>>
>> How many CPUs in your LLC?
> 
> I have tried with X86, 48 CPUs, 2 nodes, each having 24 CPUs in LLC
> +
> POWER10, Multiple CPUs with 4 CPUs in LLC
> +
> POWER9, Multiple CPUs with 8 CPUs in LLC
> 
>>
>> This is a system with 192 CPUs, 4 nodes and each node has 48 CPUs in LLC
>> domain.
>>
> 
> Okay,
> 
>> It looks like for netperf both TCP and UDP cases have the notable change
>> under 2 x overcommit, it may be not interesting though.
>>
>>
> 
> I believe the extra load on this 24 core LLC could be because we may end up
> trying to set the idle-core, even when there is no idle core available.
> 
> If possible, can you please give a try with v3 with the call to
> set_next_idle_core commented out?
> 
> 

v3 seems not be applicable on tip/sched/core 915a2bc3c6b7?

  reply	other threads:[~2021-05-17 12:48 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-06 16:45 [PATCH v2 0/8] sched/fair: wake_affine improvements Srikar Dronamraju
2021-05-06 16:45 ` [PATCH v2 1/8] sched/fair: Update affine statistics when needed Srikar Dronamraju
2021-05-07 16:08   ` Valentin Schneider
2021-05-07 17:05     ` Srikar Dronamraju
2021-05-11 11:51       ` Valentin Schneider
2021-05-11 16:22         ` Srikar Dronamraju
2021-05-06 16:45 ` [PATCH v2 2/8] sched/fair: Maintain the identity of idle-core Srikar Dronamraju
2021-05-11 11:51   ` Valentin Schneider
2021-05-11 16:27     ` Srikar Dronamraju
2021-05-06 16:45 ` [PATCH v2 3/8] sched/fair: Update idle-core more often Srikar Dronamraju
2021-05-06 16:45 ` [PATCH v2 4/8] sched/fair: Prefer idle CPU to cache affinity Srikar Dronamraju
2021-05-06 16:45 ` [PATCH v2 5/8] sched/fair: Use affine_idler_llc for wakeups across LLC Srikar Dronamraju
2021-05-06 16:45 ` [PATCH v2 6/8] sched/idle: Move busy_cpu accounting to idle callback Srikar Dronamraju
2021-05-11 11:51   ` Valentin Schneider
2021-05-11 16:55     ` Srikar Dronamraju
2021-05-12  0:32     ` Aubrey Li
2021-05-12  8:08   ` Aubrey Li
2021-05-13  7:31     ` Srikar Dronamraju
2021-05-14  4:11       ` Aubrey Li
2021-05-17 10:40         ` Srikar Dronamraju
2021-05-17 12:48           ` Aubrey Li [this message]
2021-05-17 12:57             ` Srikar Dronamraju
2021-05-18  0:59               ` Aubrey Li
2021-05-18  4:00                 ` Srikar Dronamraju
2021-05-18  6:05                   ` Aubrey Li
2021-05-18  7:18                     ` Srikar Dronamraju
2021-05-19  9:43                       ` Aubrey Li
2021-05-19 17:34                         ` Srikar Dronamraju
2021-05-06 16:45 ` [PATCH v2 7/8] sched/fair: Remove ifdefs in waker_affine_idler_llc Srikar Dronamraju
2021-05-06 16:45 ` [PATCH v2 8/8] sched/fair: Dont iterate if no idle CPUs Srikar Dronamraju
2021-05-06 16:53 ` [PATCH v2 0/8] sched/fair: wake_affine improvements Srikar Dronamraju

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