From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Andrew Morton <akpm@osdl.org>, Hugh Dickins <hugh@veritas.com>,
Andi Kleen <ak@suse.de>,
davem@davemloft.net, Linus Torvalds <torvalds@osdl.org>,
Linux Kernel list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2] page table iterators
Date: Mon, 21 Feb 2005 20:04:34 +1100 [thread overview]
Message-ID: <4219A422.5010809@yahoo.com.au> (raw)
In-Reply-To: <42199727.2010309@yahoo.com.au>
Nick Piggin wrote:
> Haven't yet pulled out a pre-4-level kernel to see how 3-level compares
> I guess I'll do that now.
>
Close.
Before 4level: 119.5us, after folded walkers: 132.8us
I think most of this is now coming from clear_page_range, rather
than the actual traversing of the page tables (because they should
be completely folded by now):
before:
4089 total 0.0017
753 kmap_atomic 4.7358
682 do_wp_page 0.6713
680 do_page_fault 0.4561
261 zap_pte_range 0.3625
176 copy_page_range 0.2133
159 pte_alloc_one 1.5743
145 clear_page_tables 0.4866
after:
4307 total 0.0018
676 kmap_atomic 4.2516
665 do_page_fault 0.4472
615 do_wp_page 0.6225
550 clear_page_range 0.9982
262 zap_pte_range 0.4870
I think the additional work done by clear_page_range (versus
clear_page_tables) justifies the extra cost, even for 3-level
architectures.
next prev parent reply other threads:[~2005-02-21 9:05 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-02-17 13:53 [PATCH 1/2] optimise copy page range Nick Piggin
2005-02-17 14:03 ` [PATCH 2/2] page table iterators Nick Piggin
2005-02-17 15:56 ` Linus Torvalds
2005-02-17 16:13 ` Nick Piggin
2005-02-17 19:43 ` Andi Kleen
2005-02-17 22:49 ` Benjamin Herrenschmidt
2005-02-17 23:03 ` Andi Kleen
2005-02-17 23:21 ` Benjamin Herrenschmidt
2005-02-17 23:34 ` Andi Kleen
2005-02-17 23:30 ` David S. Miller
2005-02-17 23:57 ` Andi Kleen
2005-02-20 12:35 ` Nick Piggin
2005-02-21 6:35 ` Hugh Dickins
2005-02-21 6:40 ` Andrew Morton
2005-02-21 7:09 ` Benjamin Herrenschmidt
2005-02-21 8:09 ` Nick Piggin
2005-02-21 9:04 ` Nick Piggin [this message]
2005-02-22 9:54 ` Nick Piggin
2005-02-23 2:06 ` Hugh Dickins
2005-02-23 4:31 ` David S. Miller
2005-02-23 4:49 ` Nick Piggin
2005-02-23 4:57 ` David S. Miller
2005-02-23 5:23 ` Nick Piggin
2005-02-23 23:52 ` Nick Piggin
2005-02-24 0:00 ` David S. Miller
2005-02-24 5:12 ` Hugh Dickins
2005-02-24 5:59 ` Nick Piggin
2005-02-24 11:58 ` Hugh Dickins
2005-02-24 19:33 ` David S. Miller
2005-02-25 10:44 ` Andi Kleen
2005-02-24 21:59 ` Nick Piggin
2005-02-24 22:32 ` Hugh Dickins
2005-02-24 22:52 ` Nick Piggin
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