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 9D6A1C4321E for ; Sun, 27 Nov 2022 09:46:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229506AbiK0JqQ (ORCPT ); Sun, 27 Nov 2022 04:46:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42500 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229526AbiK0JqP (ORCPT ); Sun, 27 Nov 2022 04:46:15 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D8BED12080 for ; Sun, 27 Nov 2022 01:45:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1669542316; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=HZriKgT8RvIKDcrqwLOlGsqsyNg3u1Uj/dHSvWpclCY=; b=PfQ94/wZANBeDtse2liWgMYOyiwf1QV78kLomt4XRNTPnvoygmTXZBhuE8KE4m4ldVGdeV HUWC02FKZmIdelOWkspTCQ5vhiN6AkJSIqUycXlrdsqev1DlQpzt2njPqGfG8wE9gpf6Wz t7WHLEMt54biHlKmCan8Dz+821hE1Ek= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-478-bjLNizmdO8O7eqTRldTnRA-1; Sun, 27 Nov 2022 04:45:12 -0500 X-MC-Unique: bjLNizmdO8O7eqTRldTnRA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4161E85A588; Sun, 27 Nov 2022 09:45:12 +0000 (UTC) Received: from T590 (ovpn-8-17.pek2.redhat.com [10.72.8.17]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D5AC840C2087; Sun, 27 Nov 2022 09:45:07 +0000 (UTC) Date: Sun, 27 Nov 2022 17:45:02 +0800 From: Ming Lei To: Yu Kuai Cc: jejb@linux.ibm.com, martin.petersen@oracle.com, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, yi.zhang@huawei.com, "yukuai (C)" Subject: Re: [PATCH RFC] scsi: core: remove unsed 'restarts' from scsi_device Message-ID: References: <20221118113052.1324140-1-yukuai1@huaweicloud.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On Sat, Nov 26, 2022 at 04:54:46PM +0800, Yu Kuai wrote: > Hi, > > 在 2022/11/18 19:30, Yu Kuai 写道: > > 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. I will look at this patch next week. Can you investigate a bit the reason why perf boost is from this patch? Thanks, Ming