Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
IronPort-SDR: z8aWKyBeMhBimhOTDgzMzG/TK+95W4ZbMAv3tfrHgG260iCQqrTt++li/OsUmuQXwYIAPqsPgi
 i+D1bK3MvpUQ==
IronPort-SDR: nyA9quQLu82kgtjugpD+ctBZqdQgKaIoN/n0LYx7gIQb7mmIxboZ3bzAs7oxGTQJrb/HrjYc/p
 rDAigRoE4M9w==
Subject: Re: [LKP] Re: 2463a604a8: netperf.Throughput_tps 12.8% improvement
To:     Bart Van Assche <bvanassche@acm.org>,
        kernel test robot <oliver.sang@intel.com>
Cc:     0day robot <lkp@intel.com>, John Garry <john.garry@huawei.com>,
        Hannes Reinecke <hare@suse.com>,
        LKML <linux-kernel@vger.kernel.org>, lkp@lists.01.org,
        "Martin K . Petersen" <martin.petersen@oracle.com>,
        Christoph Hellwig <hch@lst.de>, linux-scsi@vger.kernel.org,
        "James E.J. Bottomley" <jejb@linux.ibm.com>
References: <20210525064427.GC7744@xsang-OptiPlex-9020>
 <f572997b-8979-26bb-cb3b-9926086c4cc7@acm.org>
From:   Xing Zhengjun <zhengjun.xing@linux.intel.com>
Message-ID: <0c2d909a-d307-548b-473c-0c85d479573e@linux.intel.com>
Date:   Wed, 26 May 2021 09:50:05 +0800
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101
 Thunderbird/78.10.2
MIME-Version: 1.0
In-Reply-To: <f572997b-8979-26bb-cb3b-9926086c4cc7@acm.org>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 8bit
Content-Language: en-US
Precedence: bulk


On 5/26/2021 12:44 AM, Bart Van Assche wrote:
> On 5/24/21 11:44 PM, kernel test robot wrote:
>> FYI, we noticed a 12.8% improvement of netperf.Throughput_tps due to commit:
>>
>> commit: 2463a604a86728777ce4284214a52de46a808c9e ("[PATCH v3 2/3] Introduce enums for the SAM, message, host and driver status codes")
>> url: https://github.com/0day-ci/linux/commits/Bart-Van-Assche/Introduce-enums-for-SCSI-status-codes/20210524-105751
>> base: https://git.kernel.org/cgit/linux/kernel/git/mkp/scsi.git for-next
>>
>> in testcase: netperf
>> on test machine: 192 threads 4 sockets Intel(R) Xeon(R) Platinum 9242 CPU @ 2.30GHz with 192G memory
>> with following parameters:
>>
>> 	ip: ipv4
>> 	runtime: 300s
>> 	nr_threads: 16
>> 	cluster: cs-localhost
>> 	test: TCP_CRR
>> 	cpufreq_governor: performance
>> 	ucode: 0x5003006
>>
>> test-description: Netperf is a benchmark that can be use to measure various aspect of networking performance.
>> test-url: http://www.netperf.org/netperf/
> The above email reports a performance improvement for the networking
> subsystem while my patch only affects the SCSI subsystem and should not
> have any performance impact. I'm confused by the above feedback ...

I suspect it related with cache alignment, 2463a604a8 changes "u8" 
(size:1) to "enum xxx_status" (size: 4),  the cache alignment is better 
than before , so cause the improvement.
>
> Bart.
> _______________________________________________
> LKP mailing list -- lkp@lists.01.org
> To unsubscribe send an email to lkp-leave@lists.01.org

-- 
Zhengjun Xing