On 2018年08月19日 20:11, xiangxia.m.yue@xxxxxxxxx wrote:
From: Tonghao Zhang <xiangxia.m.yue@xxxxxxxxx>
The patch uses vhost_has_work_pending() to check if
the specified handler is scheduled, because in the most case,
vhost_has_work() return true when other side handler is added
to worker list. Use the vhost_has_work_pending() insead of
vhost_has_work().
Topology:
[Host] ->linux bridge -> tap vhost-net ->[Guest]
TCP_STREAM (netperf):
* Without the patch: 38035.39 Mbps, 3.37 us mean latency
* With the patch: 38409.44 Mbps, 3.34 us mean latency
The improvement is not obvious as last version. Do you imply there's
some recent changes of vhost that make it faster?
Thanks
Signed-off-by: Tonghao Zhang <xiangxia.m.yue@xxxxxxxxx>
---
drivers/vhost/net.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index db63ae2..b6939ef 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -487,10 +487,8 @@ static void vhost_net_busy_poll(struct vhost_net *net,
endtime = busy_clock() + busyloop_timeout;
while (vhost_can_busy_poll(endtime)) {
- if (vhost_has_work(&net->dev)) {
- *busyloop_intr = true;
+ if (vhost_has_work(&net->dev))
break;
- }
if ((sock_has_rx_data(sock) &&
!vhost_vq_avail_empty(&net->dev, rvq)) ||
@@ -513,6 +511,11 @@ static void vhost_net_busy_poll(struct vhost_net *net,
!vhost_has_work_pending(&net->dev, VHOST_NET_VQ_RX))
vhost_net_enable_vq(net, rvq);
+ if (vhost_has_work_pending(&net->dev,
+ poll_rx ?
+ VHOST_NET_VQ_RX: VHOST_NET_VQ_TX))
+ *busyloop_intr = true;
+
mutex_unlock(&vq->mutex);
}
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