From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shirley Ma Subject: Re: [PATCH V3 0/8] macvtap/vhost TX zero copy support Date: Fri, 22 Apr 2011 10:52:53 -0700 Message-ID: <1303494773.10632.22.camel@localhost.localdomain> References: <1303328216.19336.18.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: mst@redhat.com, Eric Dumazet , Avi Kivity , Arnd Bergmann , netdev@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org To: David Miller Return-path: In-Reply-To: <1303328216.19336.18.camel@localhost.localdomain> Sender: netdev-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Wed, 2011-04-20 at 12:36 -0700, Shirley Ma wrote: > I am collecting more test results against 2.6.39-rc3 kernel and will > provide the test matrix later. Single TCP_STREAM 120 secs test results over ixgbe 10Gb NIC results: Message BW(Gb/s)qemu-kvm (NumCPU)vhost-net(NumCPU) PerfTop irq/s 4K 7408.57 92.1% 22.6% 1229 4K(Orig)4913.17 118.1% 84.1% 2086 8K 9129.90 89.3% 23.3% 1141 8K(Orig)7094.55 115.9% 84.7% 2157 16K 9178.81 89.1% 23.3% 1139 16K(Orig)8927.1 118.7% 83.4% 2262 64K 9171.43 88.4% 24.9% 1253 64K(Orig)9085.85 115.9% 82.4% 2229 For message size less or equal than 2K, there is a known KVM guest TX overrun issue. With this zerocopy patch, the issue becomes more severe, guest io_exits has tripled than before, so the performance is not good. Once the TX overrun problem has been addressed, I will retest the small message size performance. Thanks Shirley