Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753633AbcKBOwp (ORCPT ); Wed, 2 Nov 2016 10:52:45 -0400 Received: from verein.lst.de ([213.95.11.211]:32906 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751708AbcKBOwn (ORCPT ); Wed, 2 Nov 2016 10:52:43 -0400 Date: Wed, 2 Nov 2016 15:52:39 +0100 From: Christoph Hellwig To: Jens Axboe Cc: axboe@kernel.dk, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, hch@lst.de Subject: Re: [PATCH 1/4] block: add scalable completion tracking of requests Message-ID: <20161102145239.GB13964@lst.de> References: <1478034325-28232-1-git-send-email-axboe@fb.com> <1478034325-28232-2-git-send-email-axboe@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1478034325-28232-2-git-send-email-axboe@fb.com> 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 Content-Length: 323 Lines: 7 On Tue, Nov 01, 2016 at 03:05:22PM -0600, Jens Axboe wrote: > For legacy block, we simply track them in the request queue. For > blk-mq, we track them on a per-sw queue basis, which we can then > sum up through the hardware queues and finally to a per device > state. what is the use case for the legacy request tracking?