Messages in this thread | | | Subject | iozone regression with 2.6.29-rc6 | From | Lin Ming <> | Date | Fri, 27 Feb 2009 17:13:59 +0800 |
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bisect locates below commits,
commit 1cf6e7d83bf334cc5916137862c920a97aabc018 Author: Nick Piggin <npiggin@suse.de> Date: Wed Feb 18 14:48:18 2009 -0800
mm: task dirty accounting fix
YAMAMOTO-san noticed that task_dirty_inc doesn't seem to be called properly for cases where set_page_dirty is not used to dirty a page (eg. mark_buffer_dirty).
Additionally, there is some inconsistency about when task_dirty_inc is called. It is used for dirty balancing, however it even gets called for __set_page_dirty_no_writeback.
So rather than increment it in a set_page_dirty wrapper, move it down to exactly where the dirty page accounting stats are incremented.
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Signed-off-by: Nick Piggin <npiggin@suse.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
below data in parenthesis is the result after above commit reverted, for example, -10% (+2%) means, iozone has ~10% regression with 2.6.29-rc6 compared with 2.6.29-rc5. and iozone has ~2% improvement with 2.6.29-rc6-revert-1cf6e7d compared with 2.6.29-rc5.
4P dual-core HT 2P qual-core 2P qual-core HT tulsa stockley Nehalem -------------------------------------------------------- iozone-rewrite -10% (+2%) -8% (0%) -10% (-7%) iozone-rand-write -50% (0%) -20% (+10%) iozone-read -13% (0%) iozone-write -28% (-1%) iozone-reread -5% (-1%) iozone-mmap-read -7% (+2%) iozone-mmap-reread -7% (+2%) iozone-mmap-rand-read -7% (+3%) iozone-mmap-rand-write -5% (0%)
Lin Ming
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