Re: [PATCH net-next v2] net: vhost: improve performance when enable busyloop

[Jason Wang <jasowang@redhat.com>]

On 2018年06月26日 13:17, xiangxia.m.yue@gmail.com wrote:
> From: Tonghao Zhang <xiangxia.m.yue@gmail.com>
>
> This patch improves the guest receive performance from
> host. On the handle_tx side, we poll the sock receive
> queue at the same time. handle_rx do that in the same way.
>
> For avoiding deadlock, change the code to lock the vq one
> by one and use the VHOST_NET_VQ_XX as a subclass for
> mutex_lock_nested. With the patch, qemu can set differently
> the busyloop_timeout for rx or tx queue.
>
> We set the poll-us=100us and use the iperf3 to test
> its throughput. The iperf3 command is shown as below.
>
> on the guest:
> iperf3  -s -D
>
> on the host:
> iperf3  -c 192.168.1.100 -i 1 -P 10 -t 10 -M 1400
>
> * With the patch:     23.1 Gbits/sec
> * Without the patch:  12.7 Gbits/sec
>
> Signed-off-by: Tonghao Zhang <zhangtonghao@didichuxing.com>

Thanks a lot for the patch. Looks good generally, but please split this 
big patch into separate ones like:

patch 1: lock vqs one by one
patch 2: replace magic number of lock annotation
patch 3: factor out generic busy polling logic to vhost_net_busy_poll()
patch 4: add rx busy polling in tx path.

And please cc Michael in v3.

Thanks