From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Naresh Rapolu <nrapolu@purdue.edu>
Cc: xen-devel@lists.xensource.com,
Stephen Spector <stephen.spector@citrix.com>
Subject: Re: boot_cpu_data differs between Xen hypervisor boot and normal pv_ops kernel boot
Date: Wed, 31 Mar 2010 11:14:10 -0700 [thread overview]
Message-ID: <4BB390F2.8080206@goop.org> (raw)
In-Reply-To: <4BB36A40.1080903@purdue.edu>
On 03/31/2010 08:29 AM, Naresh Rapolu wrote:
>
> 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 ?
The PMU hardware features are not virtualized, and are not available to
guest domains. I don't think Xen has much of a useful API to expose
these features, though oprofile was working at one point.
I agree it would be very useful to work out how to get good "perf"
support in a Xen domain.
(Stephen: It might be an interesting SoC project.)
J
prev parent reply other threads:[~2010-03-31 18:14 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-31 15:29 boot_cpu_data differs between Xen hypervisor boot and normal pv_ops kernel boot Naresh Rapolu
2010-03-31 15:43 ` Pasi Kärkkäinen
2010-03-31 17:51 ` Naresh Rapolu
2010-03-31 18:14 ` Jeremy Fitzhardinge [this message]
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