Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752144AbaFFK6d (ORCPT ); Fri, 6 Jun 2014 06:58:33 -0400 Received: from mx1.redhat.com ([209.132.183.28]:17931 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750803AbaFFK6c (ORCPT ); Fri, 6 Jun 2014 06:58:32 -0400 From: Vitaly Kuznetsov To: Jiri Slaby Cc: Greg KH , Konrad Rzeszutek Wilk , linux-kernel@vger.kernel.org, stable@vger.kernel.org, xen-devel@lists.xenproject.org, felipe.franciosi@citrix.com, roger.pau@citrix.com, jerry.snitselaar@oracle.com, axboe@kernel.dk Subject: Re: Backport request to stable of two performance related fixes for xen-blkfront (3.13 fixes to earlier trees) References: <20140514191122.GA7659@phenom.dumpdata.com> <20140604054848.GA20895@kroah.com> <53919C2B.6080606@suse.cz> Date: Fri, 06 Jun 2014 12:58:20 +0200 In-Reply-To: <53919C2B.6080606@suse.cz> (Jiri Slaby's message of "Fri, 06 Jun 2014 12:47:07 +0200") Message-ID: <87mwdqjodv.fsf@vitty.brq.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jiri Slaby writes: > On 06/04/2014 07:48 AM, Greg KH wrote: >> On Wed, May 14, 2014 at 03:11:22PM -0400, Konrad Rzeszutek Wilk wrote: >>> Hey Greg >>> >>> This email is in regards to backporting two patches to stable that >>> fall under the 'performance' rule: >>> >>> bfe11d6de1c416cea4f3f0f35f864162063ce3fa >>> fbe363c476afe8ec992d3baf682670a4bd1b6ce6 >> >> Now queued up, thanks. > > AFAIU, they introduce a performance regression. > > Vitaly? I'm aware of a performance regression in a 'very special' case when ramdisks or files on tmpfs are being used as storage, I post my results a while ago: https://lkml.org/lkml/2014/5/22/164 I'm not sure if that 'special' case requires investigation and/or should prevent us from doing stable backport but it would be nice if someone tries to reproduce it at least. I'm going to make a bunch of tests with FusionIO drives and sequential read to replicate same test Felipe did, I'll report as soon as I have data (beginning of next week hopefuly). -- Vitaly -- 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/