From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rusty Russell Subject: Re: [PATCH 09/18] virtio: use avail_event index Date: Wed, 18 May 2011 09:49:42 +0930 Message-ID: <87tycsn9lt.fsf__3716.23031464896$1305679574$gmane$org@rustcorp.com.au> 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> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20110517061031.GC26989@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: "Michael S. Tsirkin" Cc: Krishna Kumar , Carsten Otte , lguest@lists.ozlabs.org, Shirley Ma , kvm@vger.kernel.org, linux-s390@vger.kernel.org, netdev@vger.kernel.org, habanero@linux.vnet.ibm.com, Heiko Carstens , linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, steved@us.ibm.com, Christian Borntraeger , Tom Lendacky , Martin Schwidefsky , linux390@de.ibm.com List-Id: virtualization@lists.linuxfoundation.org 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)... > 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.