From: Andrew Morton <akpm@zip.com.au>
To: William Lee Irwin III <wli@holomorphy.com>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: page_add/remove_rmap costs
Date: Thu, 25 Jul 2002 00:09:40 -0700 [thread overview]
Message-ID: <3D3FA434.35113F60@zip.com.au> (raw)
In-Reply-To: <20020725045040.GD2907@holomorphy.com>
well I tried a few things.
- Disable the pte_chain_lock stuff for uniprocessor
builds.
- Disable the cpu_relax()
- shuffle struct page to put ->flags and ->count next
to each other.
Uniprocessor:
c01c9138 122 0.96649 strnlen_user
c0145860 162 1.28337 __d_lookup
c012c2c4 179 1.41805 rmqueue
c010ba68 180 1.42597 timer_interrupt
c01120ec 190 1.50519 do_page_fault
c013d910 191 1.51311 link_path_walk
c01052c8 219 1.73493 poll_idle
c0132e44 227 1.7983 page_add_rmap
c0122e00 237 1.87753 clear_page_tables
c0111e40 264 2.09142 pte_alloc_one
c0123018 287 2.27363 copy_page_range
c0124324 296 2.34493 do_anonymous_page
c012aa70 471 3.73128 kmem_cache_alloc
c0123224 483 3.82635 zap_pte_range
c01077c4 484 3.83427 page_fault
c0124490 547 4.33336 do_no_page
c012ac5c 560 4.43635 kmem_cache_free
c0132f1c 940 7.44672 page_remove_rmap
c0123cb0 2581 20.4468 do_wp_page
So page_add_rmap went away.
page_remove_rmap:
c0132f8a 1 0.106383 0 0
c0132f8d 1 0.106383 0 0
c0132f93 1 0.106383 0 0
c0132fa4 3 0.319149 0 0
c0132fa7 56 5.95745 0 0 the `for' loop
c0132fa9 2 0.212766 0 0
c0132fab 4 0.425532 0 0
c0132fb0 13 1.38298 0 0
c0132fb3 574 61.0638 0 0 if (pc->ptep == ptep)
c0132fb5 1 0.106383 0 0
c0132fb6 13 1.38298 0 0
c0132fb9 2 0.212766 0 0
c0132fba 4 0.425532 0 0
And the page_remove_rmap cost is now in the list walk.
But the SMP performance is unaltered by these changes.
c0129818 1329 2.42966 do_anonymous_page
c01338dc 1501 2.74411 page_cache_release
c0129a10 2157 3.9434 do_no_page
c0128128 2581 4.71855 copy_page_range
c0128390 2655 4.85384 zap_pte_range
c013a944 4356 7.96358 page_add_rmap
c013aaa0 8423 15.3988 page_remove_rmap
c0128ff8 8457 15.461 do_wp_page
For page_remove_rmap, 32% is the pte_chain_lock, 35%
is the list walk and 12% is the pte_chain_unlock.
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next prev parent reply other threads:[~2002-07-25 7:09 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-07-24 6:33 Andrew Morton
2002-07-24 6:48 ` William Lee Irwin III
2002-07-24 16:24 ` Rik van Riel
2002-07-24 20:15 ` Andrew Morton
2002-07-24 20:21 ` Rik van Riel
2002-07-24 20:28 ` Andrew Morton
2002-07-25 2:35 ` Rik van Riel
2002-07-25 3:08 ` William Lee Irwin III
2002-07-25 3:14 ` Martin J. Bligh
2002-07-25 4:21 ` Andrew Morton
2002-07-25 2:45 ` William Lee Irwin III
2002-07-25 4:50 ` William Lee Irwin III
2002-07-25 5:14 ` Andrew Morton
2002-07-25 5:15 ` John Levon
2002-07-25 5:30 ` William Lee Irwin III
2002-07-25 5:47 ` Andrew Morton
2002-07-25 5:42 ` William Lee Irwin III
2002-07-25 5:59 ` Andrew Morton
2002-07-25 7:09 ` Andrew Morton [this message]
2002-07-26 7:33 ` Daniel Phillips
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