From: Jason Wang <jasowang@redhat.com>
To: mst@redhat.com, kvm@vger.kernel.org,
virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Jason Wang <jasowang@redhat.com>
Subject: [PATCH V3 2/2] vhost_net: conditionally enable tx polling
Date: Wed, 1 Jun 2016 01:56:34 -0400 [thread overview]
Message-ID: <1464760594-30326-3-git-send-email-jasowang@redhat.com> (raw)
In-Reply-To: <1464760594-30326-1-git-send-email-jasowang@redhat.com>
We always poll tx for socket, this is sub optimal since:
- it will be only used when we exceed the sndbuf of the socket.
- since we use two independent polls for tx and vq, this will slightly
increase the waitqueue traversing time and more important, vhost
could not benefit from commit
9e641bdcfa4ef4d6e2fbaa59c1be0ad5d1551fd5 ("net-tun: restructure
tun_do_read for better sleep/wakeup efficiency") even if we've
stopped rx polling during handle_rx since tx poll were still left in
the waitqueue.
Fix this by conditionally enable tx polling only when -EAGAIN were
met.
Test shows about 8% improvement on guest rx pps.
Before: ~1350000
After: ~1460000
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/vhost/net.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 1d3e45f..e75ffcc 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -378,6 +378,7 @@ static void handle_tx(struct vhost_net *net)
goto out;
vhost_disable_notify(&net->dev, vq);
+ vhost_net_disable_vq(net, vq);
hdr_size = nvq->vhost_hlen;
zcopy = nvq->ubufs;
@@ -459,6 +460,8 @@ static void handle_tx(struct vhost_net *net)
% UIO_MAXIOV;
}
vhost_discard_vq_desc(vq, 1);
+ if (err == -EAGAIN)
+ vhost_net_enable_vq(net, vq);
break;
}
if (err != len)
--
1.8.3.1
next prev parent reply other threads:[~2016-06-01 5:57 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-01 5:56 [PATCH V3 0/2] vhost_net polling optimization Jason Wang
2016-06-01 5:56 ` [PATCH V3 1/2] vhost_net: stop polling socket during rx processing Jason Wang
2016-06-07 12:23 ` Michael S. Tsirkin
2016-06-07 21:46 ` David Miller
2016-06-01 5:56 ` Jason Wang [this message]
2016-06-07 12:26 ` [PATCH V3 2/2] vhost_net: conditionally enable tx polling Michael S. Tsirkin
2016-06-08 6:48 ` Jason Wang
2016-06-02 19:08 ` [PATCH V3 0/2] vhost_net polling optimization David Miller
2016-06-03 13:03 ` Michael S. Tsirkin
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