Virtio-net: Add multi queues in multi threads

In order to support 2 vq pairs for virtio-net, this patch create 2
sockets in one tap interface,  2 vq pairs(rx/tx) and 2 threads in
device model, So one vq pair has one thread and one socket in tap
corresponding.

On my SkyLake desktop with crosvm and ubuntu 18.04 guest:
If run one iperf server on host and one iperf client in guest, 2 vq
pairs has the same netwrok bandwidth as 1 vq pair, the bandwidth is
5.99Gbits/sec

If run two iperf server on host and two iperf client in guest,
In 1 vq pair mode, two iperf cliens bandwidth are 3.19Gbits/sec and
3.18Gbits/sec.
In 2 vq pairs mode, two iperf clients bandwidth are 4.87Gbits/sec and
4.86Gbits/sec.
So 2 vq pairs improve net bandwidth 52.7% compared with 1 vq pair in
this case.

BUG=chromium:1064482
TEST=Run iperf test in guest

Change-Id: I1fa14d7e24085552dc828a89a883d4a2ada34789
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2099754
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: Xiong  Zhang <xiong.y.zhang@intel.corp-partner.google.com>
Reviewed-by: Stephen Barber <smbarber@chromium.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/plugin/mod.rs b/src/plugin/mod.rs
index 1c7027f..ae7e19c 100644
--- a/src/plugin/mod.rs
+++ b/src/plugin/mod.rs
@@ -662,7 +662,7 @@ pub fn run_config(cfg: Config) -> Result<()> {
     if let Some(host_ip) = cfg.host_ip {
         if let Some(netmask) = cfg.netmask {
             if let Some(mac_address) = cfg.mac_address {
-                let tap = Tap::new(false).map_err(Error::TapOpen)?;
+                let tap = Tap::new(false, false).map_err(Error::TapOpen)?;
                 tap.set_ip_addr(host_ip).map_err(Error::TapSetIp)?;
                 tap.set_netmask(netmask).map_err(Error::TapSetNetmask)?;
                 tap.set_mac_address(mac_address)