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From: Andi Kleen <ak@suse.de>
To: Christoph Lameter <clameter@sgi.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Increase page fault rate by prezeroing V1 [1/3]: Introduce __GFP_ZERO
Date: 21 Dec 2004 23:40:34 +0100	[thread overview]
Message-ID: <p73mzw7cm1p.fsf@verdi.suse.de> (raw)
In-Reply-To: <Pine.LNX.4.58.0412211155340.1313@schroedinger.engr.sgi.com.suse.lists.linux.kernel>

Christoph Lameter <clameter@sgi.com> writes:
> @@ -0,0 +1,52 @@
> +/*
> + * Zero a page.
> + * rdi	page
> + */
> +	.globl zero_page
> +	.p2align 4
> +zero_page:
> +	xorl   %eax,%eax
> +	movl   $4096/64,%ecx
> +	shl	%ecx, %esi

Surely must be shl %esi,%ecx


> +zero_page_c:
> +	movl $4096/8,%ecx
> +	shl	%ecx, %esi

Same.

Haven't tested.

But for the one instruction it seems overkill to me to have a new
function. How about you just extend clear_page with the order argument?

BTW I think Andrea has been playing with prezeroing on x86 and
he found no benefit at all. So it's doubtful it makes any sense
on x86/x86-64.

-Andi

       reply	other threads:[~2004-12-21 22:40 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <B8E391BBE9FE384DAA4C5C003888BE6F02900FBD@scsmsx401.amr.corp.intel.com.suse.lists.linux.kernel>
     [not found] ` <41C20E3E.3070209@yahoo.com.au.suse.lists.linux.kernel>
     [not found]   ` <Pine.LNX.4.58.0412211154100.1313@schroedinger.engr.sgi.com.suse.lists.linux.kernel>
     [not found]     ` <Pine.LNX.4.58.0412211155340.1313@schroedinger.engr.sgi.com.suse.lists.linux.kernel>
2004-12-21 22:40       ` Andi Kleen [this message]
2004-12-21 22:54         ` Christoph Lameter
2004-12-22 10:53           ` Andi Kleen
2004-12-22 19:54             ` Christoph Lameter
     [not found]     ` <Pine.LNX.4.58.0412231119540.31791@schroedinger.engr.sgi.com.suse.lists.linux.kernel>
2004-12-23 20:27       ` Prezeroing V2 [0/3]: Why and When it works Andi Kleen
2004-12-23 21:02         ` Christoph Lameter
2004-12-22  1:40 Increase page fault rate by prezeroing V1 [1/3]: Introduce __GFP_ZERO Chuck Ebbert
     [not found] <B8E391BBE9FE384DAA4C5C003888BE6F02900FBD@scsmsx401.amr.corp.intel.com>
     [not found] ` <41C20E3E.3070209@yahoo.com.au>
2004-12-21 19:55   ` Increase page fault rate by prezeroing V1 [0/3]: Overview Christoph Lameter
2004-12-21 19:56     ` Increase page fault rate by prezeroing V1 [1/3]: Introduce __GFP_ZERO Christoph Lameter

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