From: Jason Wang <jasowang@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, virtualization@lists.linux-foundation.org
Subject: Re: [PATCH V2 6/6] vhost_net: correctly limit the max pending buffers
Date: Mon, 02 Sep 2013 16:37:38 +0800 [thread overview]
Message-ID: <52244E52.3060408@redhat.com> (raw)
In-Reply-To: <52243071.5090303@redhat.com>
On 09/02/2013 02:30 PM, Jason Wang wrote:
> On 09/02/2013 01:56 PM, Michael S. Tsirkin wrote:
>> > On Fri, Aug 30, 2013 at 12:29:22PM +0800, Jason Wang wrote:
>>> >> As Michael point out, We used to limit the max pending DMAs to get better cache
>>> >> utilization. But it was not done correctly since it was one done when there's no
>>> >> new buffers submitted from guest. Guest can easily exceeds the limitation by
>>> >> keeping sending packets.
>>> >>
>>> >> So this patch moves the check into main loop. Tests shows about 5%-10%
>>> >> improvement on per cpu throughput for guest tx. But a 5% drop on per cpu
>>> >> transaction rate for a single session TCP_RR.
>> > Any explanation for the drop? single session TCP_RR is unlikely to
>> > exceed VHOST_MAX_PEND, correct?
> Unlikely to exceed. Recheck the result, looks like it was not stable
> enough. Will re-test and report.
Re-tested with more iterations, result shows no difference on TCP_RR
test and 5%-10% improvement on per cpu throughput for guest tx.
Will post V3 soon.
prev parent reply other threads:[~2013-09-02 8:37 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-30 4:29 [PATCH V2 0/6] vhost code cleanup and minor enhancement Jason Wang
2013-08-30 4:29 ` [PATCH V2 1/6] vhost_net: make vhost_zerocopy_signal_used() returns void Jason Wang
2013-09-02 5:51 ` Michael S. Tsirkin
2013-09-02 6:29 ` Jason Wang
2013-08-30 4:29 ` [PATCH V2 2/6] vhost_net: use vhost_add_used_and_signal_n() in vhost_zerocopy_signal_used() Jason Wang
2013-09-02 5:50 ` Michael S. Tsirkin
2013-09-02 6:28 ` Jason Wang
2013-08-30 4:29 ` [PATCH V2 3/6] vhost: switch to use vhost_add_used_n() Jason Wang
2013-08-30 4:29 ` [PATCH V2 4/6] vhost_net: determine whether or not to use zerocopy at one time Jason Wang
2013-08-30 18:35 ` Sergei Shtylyov
2013-09-02 3:15 ` Jason Wang
2013-08-30 4:29 ` [PATCH V2 5/6] vhost_net: poll vhost queue after marking DMA is done Jason Wang
2013-08-30 16:44 ` Ben Hutchings
2013-09-02 3:06 ` Jason Wang
2014-02-12 7:38 ` Qin Chuanyu
[not found] ` <52FB24EA.3060001@huawei.com>
2014-02-12 10:06 ` Jason Wang
2014-02-12 16:01 ` Michael S. Tsirkin
2013-08-30 4:29 ` [PATCH V2 6/6] vhost_net: correctly limit the max pending buffers Jason Wang
2013-09-02 5:56 ` Michael S. Tsirkin
2013-09-02 6:30 ` Jason Wang
2013-09-02 8:37 ` Jason Wang [this message]
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