linux-kernel - Re: [RFC] i386: Remove page sized slabs for pgds and pmds

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Message-ID: <Pine.LNX.4.64.0703281401460.13743@schroedinger.engr.sgi.com>
Date:	Wed, 28 Mar 2007 14:05:54 -0700 (PDT)
From:	Christoph Lameter <clameter@....com>
To:	Andrew Morton <akpm@...ux-foundation.org>
cc:	linux-kernel@...r.kernel.org,
	William Lee Irwin III <wli@...omorphy.com>
Subject: Re: [RFC] i386: Remove page sized slabs for pgds and pmds

On Wed, 28 Mar 2007, Andrew Morton wrote:

> I would like to test qlhack on ia64, because ia64 puts pte-pages into the
> quicklists as well, but my ia64 machine is presently indisposed.

Its probably easier to set the number of cached pages to one.

> My (much) preferred way to handle all this is to remove the quicklists from
> all architectures: just use alloc_page() and free_page() for pte pages, pmd
> pages, etc.  I remain unaware of any testing whcih indicates that this
> would be a bad change.

Tried this also on x86_64 with an enhanced quicklist patch that also deals 
with ptes (at the price of not guaranteeing the free after the tlb flush):

quicklist:

real    8m56.787s
user    7m46.380s
sys     0m55.910s

real    8m58.326s
user    7m46.030s
sys     0m56.250s
 
real    8m56.900s
user    7m46.620s
sys     0m55.570s

no quicklist:

real    9m7.798s
user    7m48.340s
sys     0m58.360s

real    8m58.994s
user    7m47.980s
sys     0m54.870s

real    8m58.533s
user    7m48.030s
sys     0m54.150s

Seems that there is a slight benefit but its also barely above noise 
level.

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