On 02/01/2016 02:13 AM, w...@redhat.com wrote:
> From: Wei Xu <w...@wei-thinkpad.nay.redhat.com>
>
> 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 <w...@redhat.com>
> ---
> 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);
