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Message-ID: <3790fb8b-db91-b528-c574-b188c5d8d2fd@bytedance.com>
Date:   Wed, 22 Jun 2022 12:03:38 +0800
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Subject: Re: [PATCH v4 6/7] sched/fair: skip busy cores in SIS search
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To:     Chen Yu <yu.c.chen@intel.com>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Mel Gorman <mgorman@suse.de>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Josh Don <joshdon@google.com>,
        Tim Chen <tim.c.chen@linux.intel.com>,
        K Prateek Nayak <kprateek.nayak@amd.com>,
        "Gautham R . Shenoy" <gautham.shenoy@amd.com>,
        linux-kernel@vger.kernel.org
References: <20220619120451.95251-1-wuyun.abel@bytedance.com>
 <20220619120451.95251-7-wuyun.abel@bytedance.com>
 <20220621181442.GA37168@chenyu5-mobl1>
From:   Abel Wu <wuyun.abel@bytedance.com>
In-Reply-To: <20220621181442.GA37168@chenyu5-mobl1>
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On 6/22/22 2:14 AM, Chen Yu Wrote:
> Hi Abel,
> On Sun, Jun 19, 2022 at 08:04:50PM +0800, Abel Wu wrote:
>> Try to improve efficiency of SIS domain search by filtering out busy
>> cores, and as a result the more overloaded the system is, the less
>> cpus will be scanned.
>>
>> The filter is supposed to contain unoccupied cpus of the LLC. And we
>> propagate these cpus to the filter one at a time at core granule.
>> This can help spreading load to different cores given that the search
>> depth is limited. The chosen cpu to be propagated is guaranteed to be
>> unoccupied at that time.
>>
>> When idle cpu exists, the last one is preferred in order not to
>> conflict with periodic load balancing during which the first idle
>> cpu (if any) is chosen to be fed with tasks.
>>
> Maybe the content in cover letter could be copied into this git log for
> future reference?

Definitely. Will fix this in next version.
Thanks.