From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AA44BC43217 for ; Sat, 26 Nov 2022 08:55:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229538AbiKZIzB (ORCPT ); Sat, 26 Nov 2022 03:55:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54180 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229495AbiKZIy5 (ORCPT ); Sat, 26 Nov 2022 03:54:57 -0500 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 910A71F636; Sat, 26 Nov 2022 00:54:51 -0800 (PST) Received: from mail02.huawei.com (unknown [172.30.67.153]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4NK5C90lfMz4f3kJq; Sat, 26 Nov 2022 16:54:45 +0800 (CST) Received: from [10.174.176.73] (unknown [10.174.176.73]) by APP4 (Coremail) with SMTP id gCh0CgD3GthW1IFjS9C3BA--.57384S3; Sat, 26 Nov 2022 16:54:48 +0800 (CST) Subject: Re: [PATCH RFC] scsi: core: remove unsed 'restarts' from scsi_device To: Yu Kuai , ming.lei@redhat.com, jejb@linux.ibm.com, martin.petersen@oracle.com Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, yi.zhang@huawei.com, "yukuai (C)" References: <20221118113052.1324140-1-yukuai1@huaweicloud.com> From: Yu Kuai Message-ID: Date: Sat, 26 Nov 2022 16:54:46 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20221118113052.1324140-1-yukuai1@huaweicloud.com> Content-Type: text/plain; charset=gbk; format=flowed Content-Transfer-Encoding: 8bit X-CM-TRANSID: gCh0CgD3GthW1IFjS9C3BA--.57384S3 X-Coremail-Antispam: 1UD129KBjvdXoW7GrWkZF1UKr45Xw1xAr18Zrb_yoWDZwb_Gr WkKryDWa1UGrn2qFyUKr1qvFW8Kwn0gry5XF18XFnrXry8tayrCFWDKryYyFsxZa1kC3s7 Ar15Xa45GrsrZjkaLaAFLSUrUUUUUb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUb4kFF20E14v26r4j6ryUM7CY07I20VC2zVCF04k26cxKx2IYs7xG 6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8w A2z4x0Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Gr1j 6F4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oV Cq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0 I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r 4UM4x0Y48IcVAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwCYjI0SjxkI62AI1cAE67vI Y487MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI 0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUtVW8ZwCIc40Y 0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxV WUJVW8JwCI42IY6xAIw20EY4v20xvaj40_WFyUJVCq3wCI42IY6I8E87Iv67AKxVWUJVW8 JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjfUoOJ5UU UUU X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, ÔÚ 2022/11/18 19:30, Yu Kuai дµÀ: > From: Yu Kuai > > During code review, I found that 'restarts' is not useful anymore after > the following commits: > > 1) commit ab3cee3762e5 ("blk-mq: In blk_mq_dispatch_rq_list() "no budget" > is a reason to kick") > 2) commit d3b38596875d ("blk-mq: run queue no matter whether the request > is the last request") > 3) commit 673235f91531 ("scsi: core: Fix race between handling STS_RESOURCE > and completion") > > Now that if get budget ever failed, block layer will make sure to > trigger new run queue for the hctx. Hence there is no need to run queue > from scsi layer in this case. > Does anyone has suggestions about this patch? More info why I tried to remove this: while testing megaraid with 4 nvme with none elevator, the default queue_depth is 128, while I test it with fio 128 jobs and 1 iodepth, bw is about 4Gib/s, however, if I test with 128 jobs and 2 iodepth, bw is decreased to about 0.8Gib/s, and with this patch applied, bw can stay 4Gib/s in the later case. Thanks, Kuai