From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH net-next v2] net: vhost: improve performance when enable busyloop Date: Wed, 27 Jun 2018 18:58:24 +0300 Message-ID: <20180627185543-mutt-send-email-mst@kernel.org> References: <1529990276-61157-1-git-send-email-xiangxia.m.yue@gmail.com> <369bea44-6ebd-337a-b20b-a28a604fa2e9@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Cc: xiangxia.m.yue@gmail.com, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, Tonghao Zhang To: Jason Wang Return-path: Received: from mx3-rdu2.redhat.com ([66.187.233.73]:45706 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S965379AbeF0P60 (ORCPT ); Wed, 27 Jun 2018 11:58:26 -0400 Content-Disposition: inline In-Reply-To: <369bea44-6ebd-337a-b20b-a28a604fa2e9@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Jun 27, 2018 at 10:24:43PM +0800, Jason Wang wrote: > > > On 2018年06月26日 13:17, xiangxia.m.yue@gmail.com wrote: > > From: Tonghao Zhang > > > > 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 > > 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 Pls include host CPU utilization numbers. You can get them e.g. using vmstat. I suspect we also want the polling controllable e.g. through an ioctl. -- MST