From: Ingo Molnar <mingo@elte.hu>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Hugh Dickins <hugh@veritas.com>,
William Lee Irwin III <wli@movementarian.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux Memory Management List <linux-mm@kvack.org>
Subject: Re: pud_bad vs pud_bad
Date: Fri, 6 Feb 2009 00:42:41 +0100 [thread overview]
Message-ID: <20090205234241.GA14203@elte.hu> (raw)
In-Reply-To: <498B6325.1040401@goop.org>
* Jeremy Fitzhardinge <jeremy@goop.org> wrote:
> Ingo Molnar wrote:
>> We'd also lose a fair bit of performance (not to mention the pagetable
>> footprint doubling that Hugh already mentioned) on 32-bit PAE capable
>> systems that dont actually have RAM above 4G physical.
>
> Why's that? Do you mean directly from using PAE, or as a side-effect of
> highmem?
just the act of using PAE was measured to cause multi-percent slowdown in
fork() and exec() latencies, etc. The pagetables are twice as large so is
that really surprising?
Ingo
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next prev parent reply other threads:[~2009-02-05 23:42 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-05 18:23 Jeremy Fitzhardinge
2009-02-05 18:43 ` Ingo Molnar
2009-02-05 18:54 ` Jeremy Fitzhardinge
2009-02-05 19:10 ` Ingo Molnar
2009-02-05 19:26 ` Jeremy Fitzhardinge
2009-02-05 19:31 ` Ingo Molnar
2009-02-05 19:38 ` Hugh Dickins
2009-02-05 19:49 ` Ingo Molnar
2009-02-05 19:58 ` wli
2009-02-05 20:14 ` Hugh Dickins
2009-02-05 20:56 ` wli
2009-02-05 21:09 ` Hugh Dickins
2009-02-05 20:12 ` Hugh Dickins
2009-02-05 20:42 ` Jeremy Fitzhardinge
2009-02-05 20:51 ` Hugh Dickins
2009-02-05 21:05 ` Jeremy Fitzhardinge
2009-02-05 21:50 ` Ingo Molnar
2009-02-05 22:07 ` Jeremy Fitzhardinge
2009-02-05 23:42 ` Ingo Molnar [this message]
2009-02-06 0:08 ` Jeremy Fitzhardinge
2009-02-06 0:50 ` Ingo Molnar
2009-02-05 20:57 ` Ingo Molnar
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