From: Andi Kleen <ak@muc.de>
To: Andrew Morton <akpm@osdl.org>
Cc: linux-kernel@vger.kernel.org, peterc@gelato.unsw.edu.au
Subject: Re: Microstate Accounting for 2.6.11
Date: Fri, 11 Mar 2005 08:14:25 +0100 [thread overview]
Message-ID: <m1acpazmb2.fsf@muc.de> (raw)
In-Reply-To: <20050310200808.306caf98.akpm@osdl.org> (Andrew Morton's message of "Thu, 10 Mar 2005 20:08:08 -0800")
Andrew Morton <akpm@osdl.org> writes:
> Why does the kernel need this feature?
>
> Have you any numbers on the overhead?
It does RDTSC and lots of complicated stuff twice for each system call.
On P4 this will be extremly slow (> 1000cycles combined)
It is pretty unlikely that whatever it does justifies this extreme
overhead in a critical fast path.
-Andi
next prev parent reply other threads:[~2005-03-11 7:14 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-03-11 3:42 Peter Chubb
2005-03-11 4:08 ` Andrew Morton
2005-03-11 5:01 ` Peter Chubb
2005-03-11 7:14 ` Andi Kleen [this message]
2005-03-11 8:39 ` Peter Chubb
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