From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dietmar Hahn Subject: Re: Virtualization of the CPU Performance Monitoring Unit Date: Tue, 17 Apr 2012 08:11:19 +0200 Message-ID: <58047712.uBa5W5J32N@amur> References: <20120416173936.GD18314@phenom.dumpdata.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20120416173936.GD18314@phenom.dumpdata.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: xen-devel@lists.xen.org Cc: Konrad Rzeszutek Wilk , Lin Ming , wei.huang2@amd.com, marcus.granado@citrix.com, wei.wang2@amd.com, Konrad Rzeszutek Wilk List-Id: xen-devel@lists.xenproject.org Am Montag 16 April 2012, 13:39:36 schrieb Konrad Rzeszutek Wilk: > On Mon, Apr 16, 2012 at 04:16:07PM +0800, Lin Ming wrote: > > On Wed, Apr 11, 2012 at 10:30 PM, Lin Ming wrote: > > > > [....] > > > > >> That isn't actually true. If you run it, you will see it working > > >> in the guest - it just that it does not use the performence counters > > >> but instead uses the timer to sample data. > > > > > > Right, I mean "hardware event" does not work. > > > > > > Hardware event, for example, perf top -e cycles, does not work. > > > > Just found that vpmu is disabled by default. > > You need to pass xen boot parameter "vpmu" to make hardware event work. > > Oh, I wonder why it was disabled by default? Wei, would you know > by any chance? This had to do with a problem in the intel nehalem processors which could cause endless interrupt loops in the hypervisor if a hvm guest uses the performance counters so Keir proposed to add the vpmu boot flag. http://lists.xen.org/archives/html/xen-devel/2009-10/msg01460.html and http://lists.xen.org/archives/html/xen-devel/2009-11/msg00088.html Dietmar > > > > > > Software event, for example, perf top -e cpu-clock, works. > > > > So both hardware and software event work in DomU. > > Great! > > Excellent! > > > > > > > >> > > >> > Run "perf top", but no data was collected. > > >> > > >> Hm, I am able to collect data using Fedora Core 16 PV guest. > > >> For dom0 or domU? For dom0 there is a bug somewhere where > > > > > > For domU HVM guest. > > > I have problem to run domU PV guest. Still looking at it. > > > > > >> the machine crashes after 30 seconds or so - hadn't actually > > >> gotten to the bottom of it. There was an email thread: > > >> https://lkml.org/lkml/2012/2/12/74 about this. > > >> > > >> Patches are most welcome! > > > > Here are the patches. > > https://lkml.org/lkml/2012/4/15/12 > > Let me play with them a bit. At first glance they look ok - but I recall > Peter Z saying something about not implementing the IRQ WORKER, but I can't > recall the reasons. > > > > Regards, > > Lin Ming > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel > -- Company details: http://ts.fujitsu.com/imprint.html