From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shirley Ma Subject: Re: [PATCH 2/2] virtio_net: remove send completion interrupts and avoid TX queue overrun through packet drop Date: Tue, 22 Mar 2011 19:26:44 -0700 Message-ID: <1300847204.3441.26.camel@localhost.localdomain> References: <20110318133311.GA20623@gondor.apana.org.au> <1300498915.3441.21.camel@localhost.localdomain> <1300730587.3441.24.camel@localhost.localdomain> <20110322113649.GA17071@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Herbert Xu , rusty@rustcorp.com.au, davem@davemloft.net, kvm@vger.kernel.org, netdev@vger.kernel.org To: "Michael S. Tsirkin" Return-path: Received: from e2.ny.us.ibm.com ([32.97.182.142]:51536 "EHLO e2.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755409Ab1CWC0s (ORCPT ); Tue, 22 Mar 2011 22:26:48 -0400 In-Reply-To: <20110322113649.GA17071@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, 2011-03-22 at 13:36 +0200, Michael S. Tsirkin wrote: > diff --git a/drivers/virtio/virtio_ring.c > b/drivers/virtio/virtio_ring.c > index cc2f73e..6106017 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -185,11 +185,6 @@ int virtqueue_add_buf_gfp(struct virtqueue *_vq, > if (vq->num_free < out + in) { > pr_debug("Can't add buf len %i - avail = %i\n", > out + in, vq->num_free); > - /* FIXME: for historical reasons, we force a notify > here if > - * there are outgoing parts to the buffer. Presumably > the > - * host should service the ring ASAP. */ > - if (out) > - vq->notify(&vq->vq); > END_USE(vq); > return -ENOSPC; > } > With simply removing the notify here, it does help the case when TX overrun hits too often, for example for 1K message size, the single TCP_STREAM performance improved from 2.xGb/s to 4.xGb/s. Thanks Shirley