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Subject: Re: [RFC][PATCH 08/11] perf, x86: Implement simple LBR support
From: Peter Zijlstra <peterz@infradead.org>
To: Stephane Eranian <eranian@google.com>
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Date: Thu, 04 Mar 2010 09:58:27 +0100
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On Wed, 2010-03-03 at 22:57 +0100, Stephane Eranian wrote:
> I don't understand how LBR state is migrated when a per-thread event is moved
> from one CPU to another. It seems LBR is managed per-cpu.
> 
> Can you explain this to me?

It is not, its basically impossible to do given that the TOS doesn't
count more bits than is strictly needed.

Or we should stop supporting cpu and task users at the same time.