[XFS] Use atomic counters for ktrace buffer indexes

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ktrace_enter() is consuming vast amounts of CPU time due to the use of a
single global lock for protecting buffer index increments. Change it to
use per-buffer atomic counters - this reduces ktrace_enter() overhead
during a trace intensive test on a 4p machine from 58% of all CPU time to
12% and halves test runtime.

SGI-PV: 977546
SGI-Modid: xfs-linux-melb:xfs-kern:30537a

Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>

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David Chinner 2008-03-06 13:45:35 +11:00 • committed by Lachlan McIlroy

parent 44d814ced4

commit 6ee4752ffe

2 changed files with 9 additions and 14 deletions

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21

fs/xfs/support/ktrace.c

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2

fs/xfs/support/ktrace.h

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