linux-kernel - Re: [PATCH 6/6] x86: Allow disabling HW_BREAKPOINTS and PERF

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Message-ID: <alpine.DEB.2.02.1310081134120.24409@pianoman.cluster.toy>
Date:	Tue, 8 Oct 2013 11:42:15 -0400 (EDT)
From:	Vince Weaver <vince@...ter.net>
To:	Ingo Molnar <mingo@...nel.org>
cc:	Andi Kleen <andi@...stfloor.org>, x86@...nel.org,
	linux-kernel@...r.kernel.org, peterz@...radead.org,
	Andi Kleen <ak@...ux.intel.com>, fweisbec@...il.com
Subject: Re: [PATCH 6/6] x86: Allow disabling HW_BREAKPOINTS and
 PERF_EVENTS

On Tue, 8 Oct 2013, Ingo Molnar wrote:

> The base cost of perf is +151k - not small but a far cry from your claimed 
> +700k ...

Things might get that bad if we enable full event lists in the kernel for 
all of x86, as Power is starting to do.

The patch to add all Power7 events cfe0d8ba14a1d98245b371e486c68f37eba1ca52
increased kernel size by like 50k.  Imagine 10 different x86 event tables
times 50k each and you're talking a big chunk of memory.

Vince
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