From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Levon Subject: Re: [PATCH] TSC scaling for live migration between platforms with different TSC frequecies Date: Fri, 19 Jun 2009 09:54:25 -0400 Message-ID: <20090619135425.GC32704@movementarian.org> References: <20090618204551.GA25732@movementarian.org> <75b472a9-3150-4f39-ac85-ba8cb99f5602@default> <20090618210053.GB25732@movementarian.org> <706158FABBBA044BAD4FE898A02E4BC201BD7DBBD9@pdsmsx503.ccr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <706158FABBBA044BAD4FE898A02E4BC201BD7DBBD9@pdsmsx503.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: "Zhang, Xiantao" Cc: Dan Magenheimer , "xen-devel@lists.xensource.com" , Ian Pratt , Keir Fraser List-Id: xen-devel@lists.xenproject.org On Fri, Jun 19, 2009 at 09:21:55AM +0800, Zhang, Xiantao wrote: > > No. That's CPU0 only ('cpu == 0'). Solaris only has one system-wide > > timer tick. This is mstate accounting: every kernel/user boundary, > > every interrupt, etc. incurs at least one TSC read. (And of course > > the machine is idle.) > > So the rdtsc rate in the system is 2779.8/s per your testing ? No the rdtsc rate on a single CPU on an idle system on one mache was around that :) > If so, the performance impact can be ignored. We had done the > performance testing with sysbench oltp, and in the testing the rdtsc > rate exceeds 120000 rdtsc/sec, but even in such extreme case > perfomrance loss is still less 10%. In addition, we also measured the > emulation cost, and the result showes rdtsc can be done in 1500-1800 > cycles in emulation case. It would be really good to see some Solaris perf results. regards john