linux-kernel - Re: [PATCH 3/4] perf, x86: Use ALTERNATIVE() to check for X86_FEATURE_PERFCTR

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Message-ID: <m27har9vnq.fsf@firstfloor.org>
Date:	Mon, 18 Apr 2011 13:00:57 -0700
From:	Andi Kleen <andi@...stfloor.org>
To:	Robert Richter <robert.richter@....com>
Cc:	Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...e.hu>,
	Stephane Eranian <eranian@...gle.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/4] perf, x86: Use ALTERNATIVE() to check for X86_FEATURE_PERFCTR_CORE

Robert Richter <robert.richter@....com> writes:

> Using ALTERNATIVE() when checking for X86_FEATURE_PERFCTR_CORE avoids
> an extra pointer chase and data cache hit.

Is that really a performance critical path?

Seems more like unnecessary obfuscation to me.

-Andi


-- 
ak@...ux.intel.com -- Speaking for myself only
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