From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kip Macy Subject: Re: Hyperthreading network benchmark Date: Sat, 30 Oct 2004 18:46:27 -0700 (PDT) Message-ID: <20041030184251.L32562@demos.bsdclusters.com> References: <418440A9.4030307@users.sourceforge.net> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Return-path: In-Reply-To: <418440A9.4030307@users.sourceforge.net> Sender: xen-devel-admin@lists.sourceforge.net Errors-To: xen-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: kuas Cc: xen-devel-ml List-Id: xen-devel@lists.xenproject.org They've seen anywhere from a 30% decrease to 30% increase in performance on SPECint with hyperthreading turned on. Bear in mind you're now sharing a single cache between two processes. For many workloads the trace cache on the P4 was too small to begin with. -Kip On Sat, 30 Oct 2004, kuas wrote: > Hi all, > > I found enabling hyperthreading for Xen (the hypervisor layer) would > degrade network performance. I wonder if the synchronization cost of Xen > (the hypervisor) running on multi cores/multiprocessors environment is > high (around 30 %). The benchmark I did is against Intel Pentium 2.4 MHz > Hyperthreaded CPU and Gigabit network (ethernet and switch). I was using > WebStone 2.5 benchmark against Apache 2.0.50-1.0 (FC1 httpd package). I > was also running 2.4.27 for the domains kernel. The result I have: > 1. Native: > a. Hyperthread enabled: 370 Mb/sec > b. Hyperthread disabled: 270-290 Mb/sec > 2. Domain 0 has the same performance around: 270 Mb/sec > 3. Domain 1: > a, Hyperthreaded enabled, domain1 run on different core: 175-185 Mb/sec > b. Hyperthreaded disabled or even if enabled domain 1 is forced to > be in the same Core with domain 0: 255-265 Mb/sec > > Please note, I was only sending request to one domain at a time. It > seems when the two domain ran in the same core we had higher > performance. I wonder if any other people has done almost similar test > and have similiar/opposite behavior. Are these behaviors make sense? > > Thanks in advance for any comments. > > Kuas. > > > > > ------------------------------------------------------- > This SF.Net email is sponsored by: > Sybase ASE Linux Express Edition - download now for FREE > LinuxWorld Reader's Choice Award Winner for best database on Linux. > http://ads.osdn.com/?ad_id=5588&alloc_id=12065&op=click > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/xen-devel > ------------------------------------------------------- This SF.Net email is sponsored by: Sybase ASE Linux Express Edition - download now for FREE LinuxWorld Reader's Choice Award Winner for best database on Linux. http://ads.osdn.com/?ad_id=5588&alloc_id=12065&op=click