From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752349AbdLLR3M (ORCPT ); Tue, 12 Dec 2017 12:29:12 -0500 Received: from mail-qt0-f171.google.com ([209.85.216.171]:43027 "EHLO mail-qt0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751688AbdLLR3L (ORCPT ); Tue, 12 Dec 2017 12:29:11 -0500 X-Google-Smtp-Source: ACJfBouPS9Y1RwezU5O40UfCyyJRbyr54t3zWg9jR/Oqss/eH/ZUgpNxPVphrGVvO0WddBj9TPohOA== Date: Tue, 12 Dec 2017 09:29:08 -0800 From: Tejun Heo To: Nikolay Borisov Cc: axboe@kernel.dk, linux-kernel@vger.kernel.org, oleg@redhat.com, peterz@infradead.org, kernel-team@fb.com, osandov@fb.com Subject: Re: [PATCH 6/6] blk-mq: remove REQ_ATOM_STARTED Message-ID: <20171212172908.GG3919388@devbig577.frc2.facebook.com> References: <20171209192525.982030-1-tj@kernel.org> <20171209192525.982030-7-tj@kernel.org> <8bf8dcc8-6198-902b-5c4c-7c66c17c9fd0@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8bf8dcc8-6198-902b-5c4c-7c66c17c9fd0@suse.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Nikolay. On Tue, Dec 12, 2017 at 01:17:52PM +0200, Nikolay Borisov wrote: > On 9.12.2017 21:25, Tejun Heo wrote: > > After the recent updates to use generation number and state based > > synchronization, we can easily replace REQ_ATOM_STARTED usages by > > adding an extra state to distinguish completed but not yet freed > > state. > > > > Add MQ_RQ_COMPLETE and replace REQ_ATOM_STARTED usages with > > blk_mq_rq_state() tests. REQ_ATOM_STARTED no longer has any users > > left and is removed. > > Where are the promised in patch 5/6 performance results? Opos, I thought I removed all of those. I couldn't reliably show that this performed better. I was testing with nullblk but the run-to-run deviations were too great (they generally kept getting faster, maybe better locality?) to draw a reliable conclusion. Whatever difference in performance is unlikely to be material in actual workloads anyway. I dropped the sentence from the description. Thanks. -- tejun