From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Charbonnet Subject: Re: Opteron server and NUMA Date: Sat, 8 Oct 2005 12:21:52 -0500 Message-ID: <200510081221.52713.alexander@charbonnet.com> References: <200510061759.56310.alexander@charbonnet.com> <200510072035.51954.alexander@charbonnet.com> <2b6116b30510080416t4a6767ecs2cad0b6073872cbd@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <2b6116b30510080416t4a6767ecs2cad0b6073872cbd@mail.gmail.com> Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: xen-devel@lists.xensource.com Cc: Nicholas Lee List-Id: xen-devel@lists.xenproject.org The traffic over the local adapter between my app and MySQL may be significant. I've tried both the socket connection and the TCP connection without a big difference. I recompiled with the necessary kernel option and ran: tc qdisc add dev eth0 root tbf rate 50mbit latency 20ms burst 50k as suggested by one of your links, but there wasn't a significant difference. I used ab to benchmark grabbing a 100MB file 100 times from localhost. Natively it took 15.9 seconds. Under Domain0 it took 41% longer, 22.4 seconds. That sure looks like it makes up a huge chunk of the overall slowdown I'm noticing. Any other tricks to try to get network performance closer to native? Thanks! Alex On Saturday 08 October 2005 06:16 am, Nicholas Lee wrote: > On 10/8/05, Alexander Charbonnet wrote: > > I now think that lack of NUMA support isn't the problem. I've done some > > benchmarking of my database-backed Perl Web app with the Apache benchmark > > tool, "ab". I ran the same query with differing total requests and > > concurrency. After the first time, which I did manually before the > > tests, all the results will be in the database query cache. Therefore, I > > don't expect any disk I/O. > > Could be Net IO. One thing I note with my Xen 2.0 setup is that it > wasn't very high performance. > > There are a couple of emails I've noted but haven't had the time to try out > yet: > > http://lists.xensource.com/archives/html/xen-users/2005-08/msg00211.html > > "virtual eth devices had packet queueing disabled (txqueuelen:0 on > ifconfig), and had a 4k size max. ring buffer for > transfering packets between domains. Whenever that buffer would run > full, packets are dropped..." > > http://lists.xensource.com/archives/html/xen-users/2005-07/msg00708.html > > "The problem is that the data structure in which the ring buffer is > organized has to fit into one memory page (4096 bytes)" > > http://lists.xensource.com/archives/html/xen-devel/2005-09/msg00196.html > > "default qdisc being inadequate" > "tc qdisc add dev eth0 root tbf rate 50mbit latency 20ms burst 50k" > > > One of the problems with Xen at the moment is the lack of > documentation/cluebooks for stuff like this at the moment. Best > practice guides etc. Still a learning process. > > -- > Nicholas Lee > http://stateless.geek.nz > gpg 8072 4F86 EDCD 4FC1 18EF 5BDD 07B0 9597 6D58 D70C > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel