Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423061AbWLUTpu (ORCPT ); Thu, 21 Dec 2006 14:45:50 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1423062AbWLUTpu (ORCPT ); Thu, 21 Dec 2006 14:45:50 -0500 Received: from brick.kernel.dk ([62.242.22.158]:21471 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423061AbWLUTpt (ORCPT ); Thu, 21 Dec 2006 14:45:49 -0500 Date: Thu, 21 Dec 2006 20:47:41 +0100 From: Jens Axboe To: Andrew Morton Cc: linux-kernel@vger.kernel.org, Linus Torvalds Subject: Re: performance regression from block merge Message-ID: <20061221194741.GH17199@kernel.dk> References: <20061221112540.e4ba58bc.akpm@osdl.org> <20061221193549.GF17199@kernel.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20061221193549.GF17199@kernel.dk> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1210 Lines: 36 On Thu, Dec 21 2006, Jens Axboe wrote: > On Thu, Dec 21 2006, Andrew Morton wrote: > > > > Jens, elapsed time for `mke2fs /dev/hdc5' with the anticipatory scheduler > > (at least) has gone from nine seconds to sixty as a result of the recent > > block merge. > > About when? I'll double check and test here, I'm assuming you mean since > 2.6.19? Auch, brown paper bag time, I spotted an obvious typo in the recent merge. Does this fix it? It should be safe to kill the ->special check, but lets leave that for another time. diff --git a/block/elevator.c b/block/elevator.c index 62c7a30..536be74 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -82,7 +82,7 @@ inline int elv_rq_merge_ok(struct reques /* * must be same device and not a special request */ - if (rq->rq_disk != bio->bi_bdev->bd_disk || !rq->special) + if (rq->rq_disk != bio->bi_bdev->bd_disk || rq->special) return 0; if (!elv_iosched_allow_merge(rq, bio)) -- Jens Axboe - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/