Messages in this thread | | | Date | Wed, 21 Apr 2010 23:26:07 -0700 | From | Darren Hart <> | Subject | Lockdep usage |
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I'm having some trouble with lockstat. I've enabled CONFIG_LOCK_STATS and then run the following commands to collect the lock statistics for the futex_lock test case. I expect this test case to generate a fair amount of contention on the futex hash bucket locks, but they don't show up in the stats (in fact, nothing shows up in the stats). I have seen much longer lock_stat files when I forgot to clear them before the test, but no hb locks showed up there either.
Is my usage below incorrect? Do I have to somehow annotate the hb->lock in order for lockstat to track it?
This is as of: commit a3d3203e4bb40f253b1541e310dc0f9305be7c84 Merge: f937331... ec28dcc... Author: Linus Torvalds <torvalds@linux-foundation.org> Date: Sun Mar 14 20:29:21 2010 -0700
# echo 0 > /proc/lock_stat; echo 1 > /proc/sys/kernel/lock_stat; ./futex_lock -i10000000 -p1000 -d20; cat /proc/lock_stat > lock.lockstat; echo 0 > /proc/sys/kernel/lock_stat futex_lock: Measure FUTEX_LOCK operations per second Arguments: iterations=10000000 threads=256 adaptive=no period=1000 duty-cycle=20% Result: 731 Kiter/s
# cat lock.lockstat lock_stat version 0.3 *WARNING* lock debugging disabled!! - possibly due to a lockdep warning ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- class name con-bounces contentions waittime-min waittime-max waittime-total acq-bounces acquisitions holdtime-min holdtime-max holdtime-total -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
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Thanks,
-- Darren Hart IBM Linux Technology Center Real-Time Linux Team
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