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From: William Lee Irwin III <wli@holomorphy.com>
To: Nick Craig-Wood <ncw1@axis.demon.co.uk>
Cc: linux-kernel@vger.kernel.org, Rohit Seth <rohit.seth@intel.com>
Subject: Re: 2.6.0 Huge pages not working as expected
Date: Fri, 26 Dec 2003 03:56:47 -0800	[thread overview]
Message-ID: <20031226115647.GH27687@holomorphy.com> (raw)
In-Reply-To: <20031226105433.GA25970@axis.demon.co.uk>

On Fri, Dec 26, 2003 at 10:54:33AM +0000, Nick Craig-Wood wrote:
> I wrote a little test program to show the benefits of huge pages by
> reducing TLB thrashing - it fills up 16 MB with sequential numbers
> then adds them with different strides - very much the sort of thing
> FFTs do.  However huge pages show a performance decrease not increase
> for large strides!  For smaller ones there is a small speedup.
> I've been testing on
> processor       : 0
> vendor_id       : GenuineIntel
> cpu family      : 6
> model           : 8
> model name      : Pentium III (Coppermine)

P-III has something like 2 TLB entries usable for large pages.
I recommend trying this again on a P-IV.


-- wli

  reply	other threads:[~2003-12-26 11:56 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-12-26 10:54 2.6.0 Huge pages not working as expected Nick Craig-Wood
2003-12-26 11:56 ` William Lee Irwin III [this message]
2003-12-26 20:10   ` Nick Craig-Wood
2003-12-26 20:15     ` William Lee Irwin III
2003-12-26 20:33     ` Linus Torvalds
2003-12-27  3:36       ` Andrea Arcangeli
2003-12-27  4:01         ` Linus Torvalds
2003-12-27  9:28           ` David S. Miller
2003-12-27 15:58           ` Andrea Arcangeli
2003-12-27  9:01       ` Nick Craig-Wood
2004-01-06 14:24     ` Kurt Garloff

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