From mboxrd@z Thu Jan 1 00:00:00 1970 From: Naresh Rapolu Subject: Re: boot_cpu_data differs between Xen hypervisor boot and normal pv_ops kernel boot Date: Wed, 31 Mar 2010 13:51:34 -0400 Message-ID: <4BB38BA6.9070705@purdue.edu> References: <4BB36A40.1080903@purdue.edu> <20100331154340.GS1878@reaktio.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20100331154340.GS1878@reaktio.net> 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 List-Id: xen-devel@lists.xenproject.org Thanks Pasi, But I am concerned about the Performance Monitoring Unit (PMU). Not=20 sure if it has any link to power mgmt unit. Xen while booting believes =20 Xeon 5530 is in the P6 category and hence does not detect the Intel PMU=20 driver, thereby hindering Oprofile to use the performance counters. =20 This does not happen if I boot the kernel normally without Xen.=20 In 2.6.31.12 , the file for the same is =20 arch/x86/kernel/cpu/perf_counters.c , but dmesg doesnt show any=20 printk messages from this file when I boot with xen-3.4.2. Does Xen=20 even consider setting up the performance counters at boot time ? Did=20 anyone successfully use Oprofile in 2.6.31 kernels for hardware=20 performance events ( cache-misses ) etc ? Iam using ubuntu 8.04 LTS... Does it depend on the OS ? Can someone=20 familiar with the boot code help me please ! Thanks, Naresh Rapolu. Pasi K=E4rkk=E4inen wrote: > On Wed, Mar 31, 2010 at 11:29:04AM -0400, Naresh Rapolu wrote: > =20 >> Hello, >> >> After booting the xen-stable 2.6.32.10 pv_ops kernel from jeremy git= =20 >> tree with Xen-4.0.0-rc8 installed, >> dmesg | grep PMU shows : >> >> Performance Events : unsupported p6 CPU model 26 no PMU driver, softwa= re =20 >> events only. >> PMU:oprofile: found i386/core_i7. >> >> If I boot the same compiled kernel, without Xen installed, dmesg | gre= p =20 >> PMU shows : >> Performance Events : Nehalem/Corei7 events, Intel PMU driver. >> PMU:oprofile: found i386/core_i7. >> >> >> When I looked into the source code, arch/x86/kernel/cpu/perf_event.c,= =20 >> at run-time boot_cpu_data structure seems to differ in these two for= ms =20 >> of booting. >> Due to this, Iam not able to use the hardware performance counters in = =20 >> my Xeon 5530 processor as hardware events(cache-misses etc) are bein= g =20 >> disabled. >> >> Is there any reason for this ? >> >> =20 > > I think only xen/stable-2.6.31.x tree currently has power mgmt stuff in= cluded. > > -- Pasi > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel > =20