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From: "Li, Aubrey" <aubrey.li@linux.intel.com>
To: Valentin Schneider <valentin.schneider@arm.com>
Cc: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com,
	vincent.guittot@linaro.org, mgorman@techsingularity.net,
	qais.yousef@arm.com, dietmar.eggemann@arm.com,
	rostedt@goodmis.org, bsegall@google.com,
	tim.c.chen@linux.intel.com, linux-kernel@vger.kernel.org,
	Aubrey Li <aubrey.li@intel.com>, Mel Gorman <mgorman@suse.de>,
	Jiang Biao <benbjiang@gmail.com>
Subject: Re: [RFC PATCH v4] sched/fair: select idle cpu from idle cpumask for task wakeup
Date: Thu, 19 Nov 2020 09:13:09 +0800	[thread overview]
Message-ID: <bf7b6dd3-7922-2a4e-8df5-735b24c2dfc7@linux.intel.com> (raw)
In-Reply-To: <jhjlfeyx41f.mognet@arm.com>

On 2020/11/18 20:06, Valentin Schneider wrote:
> 
> On 16/11/20 20:04, Aubrey Li wrote:
>> From: Aubrey Li <aubrey.li@intel.com>
>>
>> Add idle cpumask to track idle cpus in sched domain. When a CPU
>> enters idle, if the idle driver indicates to stop tick, this CPU
>> is set in the idle cpumask to be a wakeup target. And if the CPU
>> is not in idle, the CPU is cleared in idle cpumask during scheduler
>> tick to ratelimit idle cpumask update.
>>
>> When a task wakes up to select an idle cpu, scanning idle cpumask
>> has low cost than scanning all the cpus in last level cache domain,
>> especially when the system is heavily loaded.
>>
>> Benchmarks were tested on a x86 4 socket system with 24 cores per
>> socket and 2 hyperthreads per core, total 192 CPUs. Hackbench and
>> schbench have no notable change, uperf has:
>>
>> uperf throughput: netperf workload, tcp_nodelay, r/w size = 90
>>
>>   threads       baseline-avg    %std    patch-avg       %std
>>   96            1               0.83    1.23            3.27
>>   144           1               1.03    1.67            2.67
>>   192           1               0.69    1.81            3.59
>>   240           1               2.84    1.51            2.67
>>
>> Cc: Mel Gorman <mgorman@suse.de>
>> Cc: Vincent Guittot <vincent.guittot@linaro.org>
>> Cc: Qais Yousef <qais.yousef@arm.com>
>> Cc: Valentin Schneider <valentin.schneider@arm.com>
>> Cc: Jiang Biao <benbjiang@gmail.com>
>> Cc: Tim Chen <tim.c.chen@linux.intel.com>
>> Signed-off-by: Aubrey Li <aubrey.li@linux.intel.com>
> 
> That's missing a v3 -> v4 change summary
> 

okay, I'll add in the next version soon.

Thanks,
-Aubrey

  reply	other threads:[~2020-11-19  1:13 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-16 20:04 [RFC PATCH v4] sched/fair: select idle cpu from idle cpumask for task wakeup Aubrey Li
2020-11-18 12:06 ` Valentin Schneider
2020-11-19  1:13   ` Li, Aubrey [this message]
2020-11-18 13:36 ` Vincent Guittot
2020-11-19  1:34   ` Li, Aubrey
2020-11-19  8:19     ` Vincent Guittot
2020-11-19 11:41       ` Li, Aubrey
2020-11-22 14:03 ` [sched/fair] 8d86968ac3: hackbench.throughput 51.7% improvement kernel test robot
2020-11-25  9:09 ` [sched/fair] 8d86968ac3: netperf.Throughput_tps -29.5% regression kernel test robot
2020-11-26  6:57   ` Li, Aubrey
2020-11-26 12:13     ` Mel Gorman
2020-12-02 14:29       ` Li, Aubrey
2020-12-02 14:48         ` Mel Gorman
2020-12-02 16:22         ` Vincent Guittot

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