From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55061) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aQA1M-00035Z-JP for qemu-devel@nongnu.org; Mon, 01 Feb 2016 03:39:41 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aQA1H-0004nU-Ic for qemu-devel@nongnu.org; Mon, 01 Feb 2016 03:39:40 -0500 Received: from mx1.redhat.com ([209.132.183.28]:39537) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aQA1H-0004mv-Al for qemu-devel@nongnu.org; Mon, 01 Feb 2016 03:39:35 -0500 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (Postfix) with ESMTPS id CF3AF8E390 for ; Mon, 1 Feb 2016 08:39:34 +0000 (UTC) Received: from wei-thinkpad.nay.redhat.com (vpn1-6-157.pek2.redhat.com [10.72.6.157]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u118dQS1013921 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Mon, 1 Feb 2016 03:39:33 -0500 Message-ID: <56AF19BD.2030706@redhat.com> Date: Mon, 01 Feb 2016 16:39:25 +0800 From: Wei Xu MIME-Version: 1.0 References: <1454264009-24094-1-git-send-email-wexu@redhat.com> <1454264009-24094-6-git-send-email-wexu@redhat.com> <56AEFB1D.70903@redhat.com> In-Reply-To: <56AEFB1D.70903@redhat.com> Content-Type: text/plain; charset=windows-1252; format=flowed 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: qemu-devel@nongnu.org On 02/01/2016 02:28 PM, Jason Wang wrote: > > 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? This is still under estimation, 300ms -500ms is a good value to adapt the test, this should be configurable. >> + >> /* 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. OK. > >> + 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? Yes, it's seg. > >> + continue; >> + } > Why need above? yes, it's optional, my maybe can help if there are extra codes after this, will remove this. > >> + } >> + >> + 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. Thanks, do you know where should i add the code? > >> + } >> +} >> >> 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); >