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;
Subject: Re: [bpf] af7ec13833: will-it-scale.per_process_ops -2.5% regression
To:     kernel test robot <rong.a.chen@intel.com>
CC:     Alexei Starovoitov <ast@kernel.org>,
        Andrii Nakryiko <andriin@fb.com>,
        Martin KaFai Lau <kafai@fb.com>,
        LKML <linux-kernel@vger.kernel.org>, <lkp@lists.01.org>
References: <20200628085032.GT5535@shao2-debian>
From:   Yonghong Song <yhs@fb.com>
Message-ID: <cb4cab43-8f13-dd2a-5c58-855d93c6e790@fb.com>
Date:   Mon, 29 Jun 2020 08:10:49 -0700
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0)
 Gecko/20100101 Thunderbird/68.9.0
In-Reply-To: <20200628085032.GT5535@shao2-debian>
Content-Type: text/plain; charset=windows-1252; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
MIME-Version: 1.0
X-MS-Exchange-MessageSentRepresentingType: 1
Received: from [IPv6:2620:10d:c085:21cf::11fb] (2620:10d:c090:400::5:c5e6) by BYAPR01CA0025.prod.exchangelabs.com (2603:10b6:a02:80::38) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3131.20 via Frontend Transport; Mon, 29 Jun 2020 15:10:51 +0000
X-Originating-IP: [2620:10d:c090:400::5:c5e6]
X-MS-PublicTrafficType: Email
X-MS-Office365-Filtering-Correlation-Id: a0215cae-6e2f-4cbc-36ab-08d81c3e9cc0
X-MS-TrafficTypeDiagnostic: BYAPR15MB3094:
X-MS-Exchange-Transport-Forked: True
X-Microsoft-Antispam-PRVS: <BYAPR15MB30948BA2273CA285FEC1DAA1D36E0@BYAPR15MB3094.namprd15.prod.outlook.com>
X-FB-Source: Internal
X-MS-Oob-TLC-OOBClassifiers: OLM:1186;
X-Forefront-PRVS: 044968D9E1
X-MS-Exchange-SenderADCheck: 1
X-Microsoft-Antispam: BCL:0;
X-Microsoft-Antispam-Message-Info: 4idhr6YpDBdGJYZYJr6/ChqREU+r7dIBIOotAEYjX34ChT8hzURV/qBK/dzUnE5tvMq9J1YPAxlFTYuyeSjM6/JfddOxVajOfsrUiHDGuAR+WzeRyPJZ7WbroMV5zwfoE7iLFUbE2o2GtS/Tza+bedHcozIqnCFq+19vi/47z5+IgGqkXVSJ44CPZGMXoii3cI56BbFLI36R8lzSemHNK/Mxb3a0J5sKRqoPCquO7KmjXr8+8GNvqW3W683SI5p+wp4uLiobY91JEgMI8Avk2+3T3oaYDYPVY3xH/63baWyD0ycPEoujWdpfBaLnLRAzqjyTPhyODpS+36OF2/s5h8m5YUwEHQ7GhBtZ1ssaBYIq9SxgXLJIWj+NHZWrkDFW6p+wcbsjlAy42BvWCPSSobbwsQXhMU+mEFgmiiz3Vbr9BnRzDFWvwBp07kGGoUkYbVmFCCgyM0zrBCP8cGahNQ==
X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:BYAPR15MB4088.namprd15.prod.outlook.com;PTR:;CAT:NONE;SFTY:;SFS:(39860400002)(366004)(376002)(136003)(396003)(346002)(31696002)(66946007)(66476007)(4326008)(66556008)(31686004)(83380400001)(6916009)(36756003)(966005)(2906002)(86362001)(53546011)(6486002)(316002)(54906003)(52116002)(478600001)(16526019)(186003)(5660300002)(8676002)(2616005)(8936002)(43740500002);DIR:OUT;SFP:1102;
X-MS-Exchange-AntiSpam-MessageData: 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
X-MS-Exchange-CrossTenant-Network-Message-Id: a0215cae-6e2f-4cbc-36ab-08d81c3e9cc0
X-MS-Exchange-CrossTenant-AuthSource: BYAPR15MB4088.namprd15.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 29 Jun 2020 15:10:51.8536
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 8ae927fe-1255-47a7-a2af-5f3a069daaa2
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: rbtDDIQ4smyxI89AmnuuEPaxF983dU06nbVyXFTAWhvny3lSIb5zcs0XHpq4iWgo
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR15MB3094
X-OriginatorOrg: fb.com
X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687
 definitions=2020-06-29_15:2020-06-29,2020-06-29 signatures=0
X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 phishscore=0 mlxscore=0
 lowpriorityscore=0 clxscore=1015 malwarescore=0 spamscore=0
 impostorscore=0 bulkscore=0 cotscore=-2147483648 suspectscore=0
 priorityscore=1501 mlxlogscore=725 adultscore=0 classifier=spam adjust=0
 reason=mlx scancount=1 engine=8.12.0-2004280000
 definitions=main-2006290103
X-FB-Internal: deliver
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org


On 6/28/20 1:50 AM, kernel test robot wrote:
> Greeting,
> 
> FYI, we noticed a -2.5% regression of will-it-scale.per_process_ops due to commit:
> 
> 
> commit: af7ec13833619e17f03aa73a785a2f871da6d66b ("bpf: Add bpf_skc_to_tcp6_sock() helper")
> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master

One of previous emails claims that
     commit: 492e639f0c222784e2e0f121966375f641c61b15 ("bpf: Add 
bpf_seq_printf and bpf_seq_write helpers")
is reponsible for 2.5% improvement for will-it-scale.per_process_ops, 
which I believe is false.

This commit should not cause regression.

Probably the variation of performance is caused by test environment 
which you may want to investigate further to reduce false alarming.
Thanks!

> 
> in testcase: will-it-scale
> on test machine: 192 threads Intel(R) Xeon(R) Platinum 9242 CPU @ 2.30GHz with 192G memory
> with following parameters:
> 
> 	nr_task: 16
> 	mode: process
> 	test: mmap1
> 	cpufreq_governor: performance
> 	ucode: 0x5002f01
> 
> test-description: Will It Scale takes a testcase and runs it from 1 through to n parallel copies to see if the testcase will scale. It builds both a process and threads based test in order to see any differences between the two.
> test-url: https://github.com/antonblanchard/will-it-scale
> 
> 
> 
> If you fix the issue, kindly add following tag
> Reported-by: kernel test robot <rong.a.chen@intel.com>
> 
> 
> Details are as below:
[...]