Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752883Ab2FRKSk (ORCPT ); Mon, 18 Jun 2012 06:18:40 -0400 Received: from ozlabs.org ([203.10.76.45]:49239 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751765Ab2FRKSj (ORCPT ); Mon, 18 Jun 2012 06:18:39 -0400 From: Rusty Russell To: Asias He Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, "Michael S. Tsirkin" , Christoph Hellwig , Minchan Kim Subject: Re: [PATCH 3/3] virtio-blk: Add bio-based IO path for virtio-blk In-Reply-To: <4FDEE0CB.1030505@redhat.com> References: <1340002390-3950-1-git-send-email-asias@redhat.com> <1340002390-3950-4-git-send-email-asias@redhat.com> <87hau9yse7.fsf@rustcorp.com.au> <4FDEE0CB.1030505@redhat.com> User-Agent: Notmuch/0.12 (http://notmuchmail.org) Emacs/23.3.1 (i686-pc-linux-gnu) Date: Mon, 18 Jun 2012 19:35:22 +0930 Message-ID: <87zk81x7dp.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 902 Lines: 21 On Mon, 18 Jun 2012 16:03:23 +0800, Asias He wrote: > On 06/18/2012 03:46 PM, Rusty Russell wrote: > > On Mon, 18 Jun 2012 14:53:10 +0800, Asias He wrote: > >> This patch introduces bio-based IO path for virtio-blk. > > > > Why make it optional? > > request-based IO path is useful for users who do not want to bypass the > IO scheduler in guest kernel, e.g. users using spinning disk. For users > using fast disk device, e.g. SSD device, they can use bio-based IO path. Users using a spinning disk still get IO scheduling in the host though. What benefit is there in doing it in the guest as well? Cheers, Rusty. -- 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/