From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59982) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aQ7yv-0007tq-F1 for qemu-devel@nongnu.org; Mon, 01 Feb 2016 01:29:02 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aQ7ys-0004Gn-7x for qemu-devel@nongnu.org; Mon, 01 Feb 2016 01:29:01 -0500 Received: from mx1.redhat.com ([209.132.183.28]:34537) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aQ7yr-0004Gh-Vg for qemu-devel@nongnu.org; Mon, 01 Feb 2016 01:28:58 -0500 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (Postfix) with ESMTPS id 837918E3C0 for ; Mon, 1 Feb 2016 06:28:57 +0000 (UTC) References: <1454264009-24094-1-git-send-email-wexu@redhat.com> <1454264009-24094-6-git-send-email-wexu@redhat.com> From: Jason Wang Message-ID: <56AEFB1D.70903@redhat.com> Date: Mon, 1 Feb 2016 14:28:45 +0800 MIME-Version: 1.0 In-Reply-To: <1454264009-24094-6-git-send-email-wexu@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC Patch v2 05/10] virtio-net rsc: Create timer to drain the packets from the cache pool List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: wexu@redhat.com, qemu-devel@nongnu.org Cc: Wei Xu , victork@redhat.com, mst@redhat.com, yvugenfi@redhat.com, marcel@redhat.com, dfleytma@redhat.com On 02/01/2016 02:13 AM, wexu@redhat.com wrote: > From: Wei Xu > > The timer will only be triggered if the packets pool is not empty, > and it'll drain off all the cached packets, this is to reduce the > delay to upper layer protocol stack. > > Signed-off-by: Wei Xu > --- > hw/net/virtio-net.c | 38 ++++++++++++++++++++++++++++++++++++++ > 1 file changed, 38 insertions(+) > > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c > index 4f77fbe..93df0d5 100644 > --- a/hw/net/virtio-net.c > +++ b/hw/net/virtio-net.c > @@ -48,12 +48,17 @@ > > #define MAX_VIRTIO_IP_PAYLOAD (65535 + IP_OFFSET) > > +/* Purge coalesced packets timer interval */ > +#define RSC_TIMER_INTERVAL 500000 Any hints for choosing this as default value? Do we need a property for user to change this? > + > /* Global statistics */ > static uint32_t rsc_chain_no_mem; > > /* Switcher to enable/disable rsc */ > static bool virtio_net_rsc_bypass; > > +static uint32_t rsc_timeout = RSC_TIMER_INTERVAL; > + > /* Coalesce callback for ipv4/6 */ > typedef int32_t (VirtioNetCoalesce) (NetRscChain *chain, NetRscSeg *seg, > const uint8_t *buf, size_t size); > @@ -1625,6 +1630,35 @@ static int virtio_net_load_device(VirtIODevice *vdev, QEMUFile *f, > return 0; > } > > +static void virtio_net_rsc_purge(void *opq) > +{ > + int ret = 0; > + NetRscChain *chain = (NetRscChain *)opq; > + NetRscSeg *seg, *rn; > + > + QTAILQ_FOREACH_SAFE(seg, &chain->buffers, next, rn) { > + if (!qemu_can_send_packet(seg->nc)) { > + /* Should quit or continue? not sure if one or some > + * of the queues fail would happen, try continue here */ This looks wrong, qemu_can_send_packet() is used for nc's peer not nc itself. > + continue; > + } > + > + ret = virtio_net_do_receive(seg->nc, seg->buf, seg->size); > + QTAILQ_REMOVE(&chain->buffers, seg, next); > + g_free(seg->buf); > + g_free(seg); > + > + if (ret == 0) { > + /* Try next queue */ Try next seg? > + continue; > + } Why need above? > + } > + > + if (!QTAILQ_EMPTY(&chain->buffers)) { > + timer_mod(chain->drain_timer, > + qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + rsc_timeout); Need stop/start the timer during vm stop/start to save cpu. > + } > +} > > static void virtio_net_rsc_cleanup(VirtIONet *n) > { > @@ -1810,6 +1844,8 @@ static size_t virtio_net_rsc_callback(NetRscChain *chain, NetClientState *nc, > if (!virtio_net_rsc_cache_buf(chain, nc, buf, size)) { > return 0; > } else { > + timer_mod(chain->drain_timer, > + qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + rsc_timeout); > return size; > } > } > @@ -1877,6 +1913,8 @@ static NetRscChain *virtio_net_rsc_lookup_chain(NetClientState *nc, > } > > chain->proto = proto; > + chain->drain_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, > + virtio_net_rsc_purge, chain); > chain->do_receive = virtio_net_rsc_receive4; > > QTAILQ_INIT(&chain->buffers);