From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zoltan Kiss Subject: Re: Poor network performance between DomU with multiqueue support Date: Tue, 02 Dec 2014 17:25:22 +0000 Message-ID: <547DF602.2040704@linaro.org> References: <547D9B00.2090506@citrix.com> <3A6795EA1206904E94BEC8EF9DF109AE23931FBB@SZXEMA512-MBX.china.huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <3A6795EA1206904E94BEC8EF9DF109AE23931FBB@SZXEMA512-MBX.china.huawei.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: "Zhangleiqiang (Trump)" , David Vrabel , zhangleiqiang , "xen-devel@lists.xen.org" Cc: "Xiaoding (B)" , Zhuangyuxin , "Luohao (brian)" , "Yuzhou (C)" List-Id: xen-devel@lists.xenproject.org On 02/12/14 11:53, Zhangleiqiang (Trump) wrote: >> -----Original Message----- >> From: xen-devel-bounces@lists.xen.org >> [mailto:xen-devel-bounces@lists.xen.org] On Behalf Of David Vrabel >> Sent: Tuesday, December 02, 2014 6:57 PM >> To: zhangleiqiang; xen-devel@lists.xen.org >> Subject: Re: [Xen-devel] Poor network performance between DomU with >> multiqueue support >> >> On 02/12/14 08:30, zhangleiqiang wrote: >>> Hi, all >>> I am testing the performance of xen netfront-netback driver that >>> with multi-queues support. The throughput from domU to remote dom0 is >>> 9.2Gb/s, but the throughput from domU to remote domU is only 3.6Gb/s, >>> I think the bottleneck is the throughput from dom0 to local domU. >>> However, we have done some testing and found the throughput from dom0 >>> to local domU is 5.8Gb/s. >>> And if we send packets from one DomU to other 3 DomUs on different >>> host simultaneously, the sum of throughout can reach 9Gbps. It seems >>> like the bottleneck is the receiver? >>> After some analysis, I found that even the max_queue of >>> netfront/back is set to 4, there are some strange results as follows: >>> 1. In domU, only one rx queue deal with softirq >>> 2. In dom0, only two netback queues process are scheduled, other >>> two process aren't scheduled. >> >> Multiqueue only has benefits if you have multiple flows since the >> source/destination addresses are hashed to a queue number. This probably >> explains why only some of the queues are being used in your test. > > The hash method you mentioned is used for selection of netback process or netfront rx queue? It's used in both direction to select the queue. > Indeed, there are 4 netback processes running in Dom0, because there are only one DomU running in Dom0 and so four netback processes are running in Dom0 (the max_queue param of netback kernel module is set to 4). > The phenomenon is that only 2 of these four netback process were running with about 70% cpu usage, and another two use little CPU. > >> David >> >> _______________________________________________ >> Xen-devel mailing list >> Xen-devel@lists.xen.org >> http://lists.xen.org/xen-devel > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel >