From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Weekes Subject: Re: Performance difference between Xen versions Date: Mon, 02 May 2011 20:39:50 -0700 Message-ID: <4DBF7906.3030909@nuclearfallout.net> References: <4DBE41C9.1010409@ts.fujitsu.com> <4DBE7819020000780003F1B6@vpn.id2.novell.com> <4DBEEF6D.8080204@nuclearfallout.net> <20110502181222.GB7498@dumpdata.com> <4DBEFB6E.4090201@nuclearfallout.net> <4DBF0306.8040000@nuclearfallout.net> <625BA99ED14B2D499DC4E29D8138F1505C885A8F4B@shsmsx502.ccr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <625BA99ED14B2D499DC4E29D8138F1505C885A8F4B@shsmsx502.ccr.corp.intel.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: "Tian, Kevin" Cc: "mark.langsdorf@amd.com" , "xen-devel@lists.xensource.com" , "Wang, Winston L" , "Wei, Gang" , Konrad Rzeszutek Wilk List-Id: xen-devel@lists.xenproject.org On 5/2/2011 8:04 PM, Tian, Kevin wrote: > > you won't know the exact frequency bumped up in the turbo mode, as it's all handled > by the CPU itself. what xen can do is just to tell the cpu now I'm OK to enter turbo > mode, which is 2268000 (1M higher than normal P0). Then CPU will decide whether > current code can be overclocked based on various conditions, such as TDP, other > core activities in the same package, ... > > One possibility to verify that turbo mode does work is to run a CPU intensive workload > on one core, while keeping other cores mostly idle. Then choose cpufreq governor > to be performance, and then compare your benchmark when BIOS turbo mode is > on/off. This should give you some feeling whether turbo mode works on your platform. Thanks for the response, Kevin. It's good to know that I can check turbo by looking to see if it's in the 1000hz-higher mode. It's a little strange to me that the true MHz level of the turbo wouldn't be known/shown, but I can live with that, as the actual performance is what counts. I'll run those benches. -John