From: Andi Kleen <andi@firstfloor.org>
To: "Yan, Zheng" <zheng.z.yan@intel.com>
Cc: a.p.zijlstra@chello.nl, eranian@google.com, mingo@elte.hu,
andi@firstfloor.org, avi@redhat.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf/x86: Disable uncore on virtualized CPU.
Date: Tue, 21 Aug 2012 16:31:15 +0200 [thread overview]
Message-ID: <20120821143115.GJ16230@one.firstfloor.org> (raw)
In-Reply-To: <1345540117-14164-1-git-send-email-zheng.z.yan@intel.com>
On Tue, Aug 21, 2012 at 05:08:37PM +0800, Yan, Zheng wrote:
> From: "Yan, Zheng" <zheng.z.yan@intel.com>
>
> Initializing uncore PMU on virtualized CPU may hang the kernel.
> This is because kvm does not emulate the entire hardware. Thers
> are lots of uncore related MSRs, making kvm enumerate them all
> is a non-trival task. So just disable uncore on virtualized CPU.
I'm not sure cpu_has_hypervisor is reliable enough for this.
Better find out why it hangs and fix that.
Early rdmsrls should be rdmsrl_safe()
Early writes in the driver should check if anything was written,
and if not then disable itself.
-Andi
next prev parent reply other threads:[~2012-08-21 14:31 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-21 9:08 Yan, Zheng
2012-08-21 12:55 ` Pekka Enberg
2012-08-31 7:12 ` Pekka Enberg
2012-08-21 14:31 ` Andi Kleen [this message]
2012-08-21 14:42 ` Pekka Enberg
2012-09-05 6:35 ` Ingo Molnar
2012-09-05 8:47 ` Peter Zijlstra
2012-09-05 9:08 ` Ingo Molnar
2012-09-05 18:52 ` Andi Kleen
2012-10-20 8:23 ` [tip:perf/urgent] perf/x86: Disable uncore on virtualized CPUs tip-bot for Yan, Zheng
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