From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756749Ab1ESH2g (ORCPT ); Thu, 19 May 2011 03:28:36 -0400 Received: from mx1.redhat.com ([209.132.183.28]:22540 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756457Ab1ESH2e (ORCPT ); Thu, 19 May 2011 03:28:34 -0400 Date: Thu, 19 May 2011 10:27:34 +0300 From: "Michael S. Tsirkin" To: Rusty Russell Cc: linux-kernel@vger.kernel.org, Carsten Otte , Christian Borntraeger , linux390@de.ibm.com, Martin Schwidefsky , Heiko Carstens , Shirley Ma , lguest@lists.ozlabs.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, Krishna Kumar , Tom Lendacky , steved@us.ibm.com, habanero@linux.vnet.ibm.com Subject: Re: [PATCH 09/18] virtio: use avail_event index Message-ID: <20110519072734.GB31253@redhat.com> References: <8bba6a0a8eee17e741c5155b04ff1b1c9f34bf94.1304541919.git.mst@redhat.com> <874o54h4rt.fsf@rustcorp.com.au> <20110515135541.GF24932@redhat.com> <87ei3zdsq2.fsf@rustcorp.com.au> <20110517061031.GC26989@redhat.com> <87tycsn9lt.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87tycsn9lt.fsf@rustcorp.com.au> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 18, 2011 at 09:49:42AM +0930, Rusty Russell wrote: > On Tue, 17 May 2011 09:10:31 +0300, "Michael S. Tsirkin" wrote: > > Well one can imagine a driver doing: > > > > while (virtqueue_get_buf()) { > > virtqueue_add_buf() > > } > > virtqueue_kick() > > > > which looks sensible (batch kicks) but might > > process any number of bufs between kicks. > > No, we currently only expose the buffers in the kick, so it can only > fill the ring doing that. > > We could change that (and maybe that's worth looking at)... That's actually what one of the early patches in the series did. I guess I can try and reorder the patches, I do believe it makes sense to publish immediately as this way host can work in parallel with the guest. > > If we look at drivers closely enough, I think none > > of them do the equivalent of the above, but not 100% sure. > > I'm pretty sure we don't have this kind of 'echo' driver yet. Drivers > tend to take OS requests and queue them. The only one which does > anything even partially sophisticated is the net driver... > > Thanks, > Rusty. I guess I'll just need to do the legwork and check then. -- MST From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH 09/18] virtio: use avail_event index Date: Thu, 19 May 2011 10:27:34 +0300 Message-ID: <20110519072734.GB31253@redhat.com> References: <8bba6a0a8eee17e741c5155b04ff1b1c9f34bf94.1304541919.git.mst@redhat.com> <874o54h4rt.fsf@rustcorp.com.au> <20110515135541.GF24932@redhat.com> <87ei3zdsq2.fsf@rustcorp.com.au> <20110517061031.GC26989@redhat.com> <87tycsn9lt.fsf@rustcorp.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Krishna Kumar , Carsten Otte , lguest-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, Shirley Ma , kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-s390-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, habanero-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org, Heiko Carstens , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, virtualization-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, steved-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org, Christian Borntraeger , Tom Lendacky , Martin Schwidefsky , linux390-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org To: Rusty Russell Return-path: Content-Disposition: inline In-Reply-To: <87tycsn9lt.fsf-8n+1lVoiYb80n/F98K4Iww@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: lguest-bounces+glkvl-lguest=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org Sender: lguest-bounces+glkvl-lguest=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org List-Id: netdev.vger.kernel.org On Wed, May 18, 2011 at 09:49:42AM +0930, Rusty Russell wrote: > On Tue, 17 May 2011 09:10:31 +0300, "Michael S. Tsirkin" wrote: > > Well one can imagine a driver doing: > > > > while (virtqueue_get_buf()) { > > virtqueue_add_buf() > > } > > virtqueue_kick() > > > > which looks sensible (batch kicks) but might > > process any number of bufs between kicks. > > No, we currently only expose the buffers in the kick, so it can only > fill the ring doing that. > > We could change that (and maybe that's worth looking at)... That's actually what one of the early patches in the series did. I guess I can try and reorder the patches, I do believe it makes sense to publish immediately as this way host can work in parallel with the guest. > > If we look at drivers closely enough, I think none > > of them do the equivalent of the above, but not 100% sure. > > I'm pretty sure we don't have this kind of 'echo' driver yet. Drivers > tend to take OS requests and queue them. The only one which does > anything even partially sophisticated is the net driver... > > Thanks, > Rusty. I guess I'll just need to do the legwork and check then. -- MST