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 X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2B57DC433E0 for ; Fri, 22 Jan 2021 19:56:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EF5D12343E for ; Fri, 22 Jan 2021 19:56:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728323AbhAVTzt (ORCPT ); Fri, 22 Jan 2021 14:55:49 -0500 Received: from mx2.suse.de ([195.135.220.15]:34156 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728123AbhAVOLx (ORCPT ); Fri, 22 Jan 2021 09:11:53 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 23267AE53; Fri, 22 Jan 2021 14:11:06 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id C7F0A1E14C3; Fri, 22 Jan 2021 15:11:05 +0100 (CET) Date: Fri, 22 Jan 2021 15:11:05 +0100 From: Jan Kara To: Jens Axboe Cc: linux-block@vger.kernel.org, Ming Lei , Jan Kara Subject: Re: [PATCH 0/2 v3] blk-mq: Improve performance of non-mq IO schedulers with multiple HW queues Message-ID: <20210122141105.GA19988@quack2.suse.cz> References: <20210111164717.21937-1-jack@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210111164717.21937-1-jack@suse.cz> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Mon 11-01-21 17:47:15, Jan Kara wrote: > Hello! > > This patch series aims to fix a regression we've noticed on our test grid when > support for multiple HW queues in megaraid_sas driver was added during the 5.10 > cycle (103fbf8e4020 scsi: megaraid_sas: Added support for shared host tagset > for cpuhotplug). The commit was reverted in the end for other reasons but I > believe the fundamental problem still exists for any other similar setup. The > problem manifests when the storage card supports multiple hardware queues > however storage behind it is slow (single rotating disk in our case) and so > using IO scheduler such as BFQ is desirable. See the second patch for details. > > Changes since v2 > * Modified code to avoid useless sbitmap_any_set() calls on submit path > > Changes since v1 > * Fixed queue running code to don't leave pending requests that bypass IO > scheduler. Jens, can you please pickup these patches? Thanks! Honza -- Jan Kara SUSE Labs, CR