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Tue, 24 Jan 2023 14:55:34 +0000 Received: from PH0PR10MB5706.namprd10.prod.outlook.com ([fe80::560e:9c52:a6bd:4036]) by PH0PR10MB5706.namprd10.prod.outlook.com ([fe80::560e:9c52:a6bd:4036%8]) with mapi id 15.20.6043.009; Tue, 24 Jan 2023 14:55:34 +0000 Message-ID: <1f02fc92-18e8-3c68-8a31-36b4e4a07efd@oracle.com> Date: Tue, 24 Jan 2023 22:55:25 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.3.0 Subject: Re: [PATCH 04/34] btrfs: remove the direct I/O read checksum lookup optimization Content-Language: en-US To: Christoph Hellwig , Chris Mason , Josef Bacik , David Sterba Cc: Damien Le Moal , Naohiro Aota , Johannes Thumshirn , Qu Wenruo , Jens Axboe , "Darrick J. Wong" , linux-block@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org References: <20230121065031.1139353-1-hch@lst.de> <20230121065031.1139353-5-hch@lst.de> From: Anand Jain In-Reply-To: <20230121065031.1139353-5-hch@lst.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: SG2PR06CA0196.apcprd06.prod.outlook.com (2603:1096:4:1::28) To PH0PR10MB5706.namprd10.prod.outlook.com (2603:10b6:510:148::10) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH0PR10MB5706:EE_|DM4PR10MB6230:EE_ X-MS-Office365-Filtering-Correlation-Id: b3dd805b-6fdd-4126-845c-08dafe1b0bc2 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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definitions=2023-01-23_12,2023-01-24_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 mlxlogscore=999 malwarescore=0 mlxscore=0 bulkscore=0 adultscore=0 phishscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2212070000 definitions=main-2301240135 X-Proofpoint-GUID: AIk87E0R6l84d_ISiyR5bj65AOze8006 X-Proofpoint-ORIG-GUID: AIk87E0R6l84d_ISiyR5bj65AOze8006 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 21/01/2023 14:50, Christoph Hellwig wrote: > To prepare for pending changes drop the optimization to only look up > csums once per bio that is submitted from the iomap layer. In the > short run this does cause additional lookups for fragmented direct > reads, but later in the series, the bio based lookup will be used on > the entire bio submitted from iomap, restoring the old behavior > in common code. > > Signed-off-by: Christoph Hellwig Reviewed-by: Anand Jain I was curious about the commit message. I ran fio to test the performance before and after the change. The results were similar. fio --group_reporting=1 --directory /mnt/test --name dioread --direct=1 --size=1g --rw=read --runtime=60 --iodepth=1024 --nrfiles=16 --numjobs=16 before this patch READ: bw=8208KiB/s (8405kB/s), 8208KiB/s-8208KiB/s (8405kB/s-8405kB/s), io=481MiB (504MB), run=60017-60017msec after this patch READ: bw=8353KiB/s (8554kB/s), 8353KiB/s-8353KiB/s (8554kB/s-8554kB/s), io=490MiB (513MB), run=60013-60013msec