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Re: [Xen-devel] boot_cpu_data differs between Xen hypervisor boot and no

To: Naresh Rapolu <nrapolu@xxxxxxxxxx>
Subject: Re: [Xen-devel] boot_cpu_data differs between Xen hypervisor boot and normal pv_ops kernel boot
From: Pasi Kärkkäinen <pasik@xxxxxx>
Date: Wed, 31 Mar 2010 18:43:40 +0300
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On Wed, Mar 31, 2010 at 11:29:04AM -0400, Naresh Rapolu wrote:
> Hello,
> After booting  the  xen-stable pv_ops kernel from jeremy git  
> tree  with Xen-4.0.0-rc8 installed,
> dmesg | grep PMU  shows :
> Performance Events : unsupported p6 CPU model 26 no PMU driver, software  
> events only.
> PMU:oprofile: found i386/core_i7.
> If I boot the same compiled kernel, without Xen installed, dmesg | grep  
> 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,    
> at run-time boot_cpu_data  structure seems to differ  in these two forms  
> of booting.
> Due to this, Iam not able to use the hardware performance counters in   
> my Xeon 5530 processor  as  hardware events(cache-misses etc) are being  
> disabled.
> Is there any reason for this ?

I think only xen/stable-2.6.31.x tree currently has power mgmt stuff included.

-- Pasi

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