Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754904Ab0GLNXW (ORCPT ); Mon, 12 Jul 2010 09:23:22 -0400 Received: from mail-ww0-f44.google.com ([74.125.82.44]:53241 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753989Ab0GLNXV convert rfc822-to-8bit (ORCPT ); Mon, 12 Jul 2010 09:23:21 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=OMwfl4awNuP2xHJFfKZ55ZZqshMoYuPxwEz/lPhmrkOxccvDDnQocAK4IYtq8ltBgb ULQ7WwVrKcqrjNzm+A3p0dJnDWIxJAUUH7cN8/6QCWoc1Bxzopexx8ovlSwt+vKYjLYx iiM3nZlSc+Blrr702K4CyuP/HrpuKW3wJG2sI= MIME-Version: 1.0 In-Reply-To: <4C3AC187.2080909@gmail.com> References: <4C3ABF96.9070405@msgid.tls.msk.ru> <4C3AC187.2080909@gmail.com> Date: Mon, 12 Jul 2010 15:15:31 +0200 Message-ID: Subject: Re: BTRFS: Unbelievably slow with kvm/qemu From: Giangiacomo Mariotti To: "Justin P. Mattock" Cc: Michael Tokarev , linux-kernel@vger.kernel.org, linux-fsdevel , qemu-devel Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1524 Lines: 36 On Mon, Jul 12, 2010 at 9:17 AM, Justin P. Mattock wrote: > On 07/12/2010 12:09 AM, Michael Tokarev wrote: >> >> This looks quite similar to a problem with ext4 and O_SYNC which I >> reported earlier but no one cared to answer (or read?) - there: >> http://permalink.gmane.org/gmane.linux.file-systems/42758 >> (sent to qemu-devel and linux-fsdevel lists - Cc'd too).  You can >> try a few other options, esp. cache=none and re-writing some guest >> files to verify. >> >> /mjt > > cool a solution... glad to see... no chance at a bisect with this? > (getting this down too a commit or two makes things easier) > > Justin P. Mattock > I didn't even say what kernel version I was using, sorry! Kernel 2.6.34.1+"patches in stable queue for next stable release". I tried this some time ago with 2.6.33.x(don't remember which version exactly) and it had the same problem, but at the time I stopped trying thinking that it was a kvm problem. So basically there's no known(to me) good version and no, I can't bisect this because this is my production system. Anyway, I suspect this is reproducible. Am I the only one who created a virtual hd file on a Btrfs and then used it with kvm/qemu? I mean, it's not a particularly exotic test-case! -- Giangiacomo -- 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/