From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752347AbaFWHJy (ORCPT ); Mon, 23 Jun 2014 03:09:54 -0400 Received: from verein.lst.de ([213.95.11.211]:39848 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752152AbaFWHJx (ORCPT ); Mon, 23 Jun 2014 03:09:53 -0400 Date: Mon, 23 Jun 2014 09:09:51 +0200 From: Christoph Hellwig To: "Elliott, Robert (Server Storage)" Cc: Bart Van Assche , Jens Axboe , Christoph Hellwig , James Bottomley , "linux-scsi@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: scsi-mq Message-ID: <20140623070951.GB12267@lst.de> References: <1402580946-11470-1-git-send-email-hch@lst.de> <53A05068.4080702@acm.org> <53A10B3A.6050705@kernel.dk> <53A13B19.2010305@acm.org> <94D0CD8314A33A4D9D801C0FE68B402958B41923@G9W0745.americas.hpqcorp.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <94D0CD8314A33A4D9D801C0FE68B402958B41923@G9W0745.americas.hpqcorp.net> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jun 21, 2014 at 12:52:22AM +0000, Elliott, Robert (Server Storage) wrote: > Some of those context switches might be from scsi_end_request(), > which always schedules the scsi_requeue_run_queue() function via the > requeue_work workqueue for scsi-mq. That causes lots of context > switches from a busy application thread (e.g., fio) to a > kworker thread. Jens has been prodding me to fix this up, I'll send a patch soon that avoids the workqueue unless we need to kick other queues and thus walk the list of LUNs.