From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46518) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aQEa2-0007Vk-H0 for qemu-devel@nongnu.org; Mon, 01 Feb 2016 08:31:52 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aQEZv-0007CH-9G for qemu-devel@nongnu.org; Mon, 01 Feb 2016 08:31:44 -0500 Received: from mx1.redhat.com ([209.132.183.28]:36752) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aQEZv-0007C8-1z for qemu-devel@nongnu.org; Mon, 01 Feb 2016 08:31:39 -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 2462E70D78 for ; Mon, 1 Feb 2016 13:31:38 +0000 (UTC) Message-ID: <56AF5E30.4090202@redhat.com> Date: Mon, 01 Feb 2016 21:31:28 +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> <56AF19BD.2030706@redhat.com> <56AF25D9.5020707@redhat.com> In-Reply-To: <56AF25D9.5020707@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: Jason Wang , qemu-devel@nongnu.org On 02/01/2016 05:31 PM, Jason Wang wrote: > > On 02/01/2016 04:39 PM, Wei Xu wrote: >> 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? > You may want to look at the vmstate change handler in virtio-net.c. great, thanks a lot. >