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Message-ID: <f7a0d098ac635c9596d739515efd4f1bc383c73e.camel@linux.intel.com>
Subject: Re: [PATCH v4 2/2] sched/fair: Scan cluster before scanning LLC in
 wake-up path
From:   Tim Chen <tim.c.chen@linux.intel.com>
To:     Yicong Yang <yangyicong@huawei.com>,
        Yicong Yang <yangyicong@hisilicon.com>, peterz@infradead.org,
        mingo@redhat.com, juri.lelli@redhat.com,
        vincent.guittot@linaro.org, gautham.shenoy@amd.com,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc:     dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com,
        bristot@redhat.com, prime.zeng@huawei.com,
        jonathan.cameron@huawei.com, ego@linux.vnet.ibm.com,
        srikar@linux.vnet.ibm.com, linuxarm@huawei.com, 21cnbao@gmail.com,
        guodong.xu@linaro.org, hesham.almatary@huawei.com,
        john.garry@huawei.com, shenyang39@huawei.com,
        Chen Yu <yu.c.chen@intel.com>
Date:   Fri, 10 Jun 2022 14:19:57 -0700
In-Reply-To: <4ab2c422-04ae-3199-ae2a-357c3270cd05@huawei.com>
References: <20220609120622.47724-1-yangyicong@hisilicon.com>
         <20220609120622.47724-3-yangyicong@hisilicon.com>
         <c3fa2b4f5884e5ad4efda48b1bb2ab4f7a2e532a.camel@linux.intel.com>
         <4ab2c422-04ae-3199-ae2a-357c3270cd05@huawei.com>
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On Fri, 2022-06-10 at 14:39 +0800, Yicong Yang wrote:
> 
> 
> I've tested this patch with MySQL as well (like in v2). This won't hurt
> the MySQL case with SIS_PROP but observed some improvement with SIS_UTIL
> posted in [1]. We leverage the nr to suppress redundant scanning in the
> current approach and seems SIS_UTIL is more efficient in this case.
> 
> 			 5.19-rc1		   patched	 patched+SIS_UTIL[1]
> TPS-16threads		  6215.11	  6172.74 (-0.68%)	  6217.33 (0.04%)
> QPS-16threads		124302.21	123454.68 (-0.68%)	124346.52 (0.04%)
> avg-lat-16threads	     2.57	     2.59 (-0.65%)	     2.57 (0.00%)
> TPS-24threads		  8726.40	  8690.87 (-0.41%)	  8833.08 (1.22%)
> QPS-24threads		174527.88	173817.42 (-0.41%)	176661.54 (1.21%)
> avg-lat-24threads	     2.75	     2.76 (-0.36%)	     2.71 (1.33%)
> TPS-32threads		  9555.42	  9514.86 (-0.42%)	 10010.87 (4.77%)
> QPS-32threads		191108.37	190297.28 (-0.42%)	200217.35 (4.55%)
> avg-lat-32threads	     3.35	     3.36 (-0.30%)	     3.20 (4.58%)
> TPS-64threads		 10290.10	 10324.75 (0.34%)	 10819.77 (5.15%)
> QPS-64threads		205802.05	206494.95 (0.34%)	216395.40 (4.90%)
> avg-lat-64threads	     6.22	     6.20 (0.38%)	     5.92 (4.88%)
> 

Thanks for the numbers. SIS_UTIL will keep off migrations off the cluster
that doesn't really improve overall utilization.  We have higher chance that
L2 cache is warm.  So it makes sense that we see a bit
better performance there.

Tim