Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Chaitanya Kulkarni <chaitanyak@nvidia.com>
To:     Michael Marod <michael@michaelmarod.com>
CC:     Keith Busch <kbusch@kernel.org>,
        Christoph Hellwig <hch@infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>
Subject: Re: NVME performance regression in Linux 5.x due to lack of block
 level IO queueing
Thread-Topic: NVME performance regression in Linux 5.x due to lack of block
 level IO queueing
Thread-Index: AQHYRJPdEASHqlgOOkeQA9+5bxa47KzY6EUAgAE61YCAADOygIAACOsA
Date:   Fri, 1 Apr 2022 02:59:00 +0000
Message-ID: <a00e3a0d-8dff-c845-ed3b-9dc435187ecd@nvidia.com>
References: <51E3A396-F68B-496D-AE36-B0457A3B0968@michaelmarod.com>
 <847D3821-1D92-468C-88C3-34284BA7922E@michaelmarod.com>
 <C06B8EF0-BF3B-4F14-994F-F80B5102D538@michaelmarod.com>
 <YkUvgu6VxNORv8M6@infradead.org>
 <4034AD9F-2A6A-4AE6-B5FC-58FC2BC238F5@michaelmarod.com>
 <YkZi+co1HchfRafa@kbusch-mbp.dhcp.thefacebook.com>
In-Reply-To: <YkZi+co1HchfRafa@kbusch-mbp.dhcp.thefacebook.com>
Accept-Language: en-US
Content-Language: en-US
user-agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.3.0
x-ms-exchange-antispam-messagedata-chunkcount: 1
x-ms-exchange-antispam-messagedata-0: =?utf-8?B?NkdOcnd1dWFYM1pTcG9uaVdRSUxVYXZVQXk3WmhQbDBYd2VJdm9jSXF0UFVr?=
 =?utf-8?B?QlBYaDBFN2JjRGFrektkeUdpbFVVNld5SWV3OHlCUmFHQ3h3aUM1SEhVY0Z6?=
 =?utf-8?B?TjZyMjVvTmJEcXIvUFY1QVp2VGRwQXdISmdSRGMzSnliVUNMUzNFUmxvK1c2?=
 =?utf-8?B?RTNzZkNBTkZhMXFaSjFwZ0ZGMVUxbTBvQzRwOExsUHQ4MnQwVUw1a0hLaE9k?=
 =?utf-8?B?VGZHUlFLMzNkTGg1SUFKZ3liNzEvR2RUU1BaU2JCSnY0UVRUbFpFMUI3a2VT?=
 =?utf-8?B?WEkwb3E5UEgvSnlRL0xBVEpsbktjbjR5QlJ0a3pOVmMya2x2ZGZaeXNiNjV3?=
 =?utf-8?B?OFZodXhNVG1id3JoVjd0U0JlTFRyU0NuWDNLMXdNMVdTNXoyVk51TjBhSzdF?=
 =?utf-8?B?K3gxS2V5VUZWNVJ4SllFcFY1aFl6KzdyWjU4c2tMTmdEbnhUSHdRYU95VzMz?=
 =?utf-8?B?YTVKQnducGxqMDZYam1NTW1HZkxMcHNZSHBRd04rVnk1UVVDa0pUNURFeENK?=
 =?utf-8?B?M1dDVXFFVFFURFBUcDNkdmREQ2JUZERuaGxkSkt4NG9rYThXeDdaSUx5cmlh?=
 =?utf-8?B?Ny8rZjlITHFSNzVBWnRucnVjYVg3U2JSbTVCaGJnR2FNUlFXMzNDZDU4d05q?=
 =?utf-8?B?TkVSdVltL0tSNlRjZVpwVjBwTk9yRWp6UytKZm5sV2pNbFpZK0dSeHJCallu?=
 =?utf-8?B?NHpFTlZXaloxY1cvOWc2TlJLVG1WbFJCbDhpMDNPKzlzeEZsQmd5Ui9HbzNG?=
 =?utf-8?B?aEJLeWlCb3RxazhVWU81bjJnb2ZRNUhQczNEWFlIcGZSSmRqdE9yUE0rMmZH?=
 =?utf-8?B?NzRDRVlXdjF4aHovTXRqRXltbmRyZ2hVTXZFZXZiMC9GUm8yOFNQU0JxYmI4?=
 =?utf-8?B?N3owc0U5R1F3OEhmTWp3NmRLWGFLcUZ5U2FnSEI1djJRZ0RoMkhlVmdldkxl?=
 =?utf-8?B?eTA3aXVHMU9lUHdDUEMyYzFLR2dBbllDOGlUQU9tWE1vRWtaOXdKWVZsWUw4?=
 =?utf-8?B?bVY0K2JZOFNTUHBOQ25pclk5amxiNldJeEErbndJUGxrVDgvRUJ0YVNXZlhF?=
 =?utf-8?B?TC94UjQ2Zzd3RVdTc2FyaTZvbi8yaHNCZWRQYkNiS01TWjRaMHlJSTBZY2dO?=
 =?utf-8?B?TnZSNEtHWG1wQXM1bnVnL044QStUbk1xLzB3TEpPQVRUanQrcEhUZDA0SzFm?=
 =?utf-8?B?bmpkK1BnOUlXSm5xT3dlVHVMT1p5ai8wTEdDM2xxUlFIbm52eklacFd0ZG9U?=
 =?utf-8?B?ek9RUUo0dzBGYWQxc1FoRDJRT0VDa1Z5cEx5MjBmM1Z1bG8xTk9hTkp1MUhY?=
 =?utf-8?B?SGhuZXBlVHFMN1ZjT0NOdmMwemdPckFiaFIzMTNNNWY5MG9NbFd3RnJ3VGEv?=
 =?utf-8?B?OVF6d1ZFTXdmd1pLSFVlbmh2ckZZWXNCSjRXTzVKTjlLZ1VkSXppcGsvdDEr?=
 =?utf-8?B?dVkzSG1XN2R0MU1DL1FBbGxZTlN0MHBtakg2SDMraXRXWGdPUEI2RngyRXl4?=
 =?utf-8?B?WjExWjUvOWpjYXNxNFMrTU0vblo2RjhvQStHT0lydmowTEJ2czJRQXhLQ004?=
 =?utf-8?B?b2NsRmdMZGtPdmllbWw4VUUxTXI4OWgyQ1VqSkRqcHA3enlqOGhTYzc4Zm5t?=
 =?utf-8?B?d0w4OHltMkF4T2NNSDlpZ3VJTll4czZGandRZ2dGcEFEUlFMbVRnYVBnWDE5?=
 =?utf-8?B?YVhtWmFZWHpmL3Z0UUhqYXJxWnk3bVRoY3RtS09HKzBhYWlYSFllSzc1Tm9v?=
 =?utf-8?B?M2tFaHYzSEgyTU03MFFxYnBoNnJsN2t6RUhNY0plTkx6S2pjOVZWVnZRVTBx?=
 =?utf-8?B?SGRVRmJoNlQwSkdGZ090TjdKdXZ6Rnp3ZXRJcTZLZVZETTVyRzhqMVZhbnVv?=
 =?utf-8?B?OVFOa0VrZHJqM0VzL0U1OHM1REduRC94Q2NSYnpTcUpvN3dJMXJnTEpIbzN3?=
 =?utf-8?B?OEdZN09MQ1oyUG91TERaT3d5WUY1ZlQzWHpFVjE3ZGJwMGl5enBqRFM0dmV2?=
 =?utf-8?B?aVRrS3FsM3BRTmdTQW1ZMlI3c2RZNytZYUVkSmVleUlSblhsbVE3S0JiUTFu?=
 =?utf-8?B?UzBFR0haRGlOcExjQm5paFFReG9XZ0puelF2Qzg3QzV4UzgyUG9jZlBHeGxF?=
 =?utf-8?B?a1ExM1hRc29vS1IvLzlaK2ZrR01lcTNUeTg1d2hEVFlJMGw0NkRKRVIyd00r?=
 =?utf-8?B?YVp0ZHFMZ3Rnd3dFU0ozWGZhMm1nNFBBU250V1R6eXB5SE1saXp0QkVnVW9h?=
 =?utf-8?B?eS84MjAwaDVvVWVEcmpiajRMQXJ6NG9JNWd5U0VCakJBbytobGJscTMzWTdH?=
 =?utf-8?B?Qk41enpBYnZnVCt2bjRzY1c5QVZIaXpmK3FqbkZYZzNhc3phdjlvdz09?=
Content-Type: text/plain; charset="utf-8"
Content-ID: <15BE18793FA91245B52938A38ED65B84@namprd12.prod.outlook.com>
Content-Transfer-Encoding: base64
MIME-Version: 1.0
X-OriginatorOrg: Nvidia.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-AuthSource: MW2PR12MB4667.namprd12.prod.outlook.com
X-MS-Exchange-CrossTenant-Network-Message-Id: a9dc105d-cb90-48ef-8417-08da138b92be
X-MS-Exchange-CrossTenant-originalarrivaltime: 01 Apr 2022 02:59:00.8750
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 43083d15-7273-40c1-b7db-39efd9ccc17a
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: PaYuMZ3lXx+ICgYckHbIfcswr0bx/BfeqIoVpR78OXSxFtIDQ9r58qubV5GTPU1XEEHCJexktYxyFe+oCgoZQw==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR12MB3759
X-Spam-Status: No, score=-1.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,
        DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FORGED_SPF_HELO,
        NICE_REPLY_A,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_PASS,
        SPF_NONE,T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no
        version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
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=