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author | des <des@FreeBSD.org> | 2002-04-15 19:42:15 +0000 |
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committer | des <des@FreeBSD.org> | 2002-04-15 19:42:15 +0000 |
commit | 918591700f3436e0726e5abdb0752a2f18cc4e38 (patch) | |
tree | 9f669bfef53400b08a62c82c5f77e45bdd6f37b1 /sys/conf | |
parent | 1c6c608da67b0477f52e0ca40ba6c03f378c4420 (diff) | |
download | FreeBSD-src-918591700f3436e0726e5abdb0752a2f18cc4e38.zip FreeBSD-src-918591700f3436e0726e5abdb0752a2f18cc4e38.tar.gz |
Document WITNESS_PROFILING.
Submitted by: Hiten Pandya <hiten@uk.FreeBSD.org>
Diffstat (limited to 'sys/conf')
-rw-r--r-- | sys/conf/NOTES | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/sys/conf/NOTES b/sys/conf/NOTES index 33a0e79..1914f54 100644 --- a/sys/conf/NOTES +++ b/sys/conf/NOTES @@ -134,6 +134,28 @@ options WITNESS options WITNESS_DDB options WITNESS_SKIPSPIN +# +# MUTEX_PROFILING - Profiling mutual exclusion locks (mutexes). This +# records four numbers for each acquisition point (identified by +# source file name and line number): longest time held, total time held, +# number of non-recursive acquisitions, and average time held. Measurements +# are made and stored in nanoseconds (using nanotime(9)), but are presented +# in microseconds, which should be sufficient for the locks which actually +# want this (those that are held long and / or often). The MUTEX_PROFILING +# option has the following sysctl namespace for controlling and viewing its +# operation: +# +# debug.mutex.prof.enable - enable / disable profiling +# debug.mutex.prof.acquisitions - number of mutex acquisitions held +# debug.mutex.prof.records - number of acquisition points recorded +# debug.mutex.prof.maxrecords - max number of acquisition points +# debug.mutex.prof.rejected - number of rejections (due to full table) +# debug.mutex.prof.hashsize - hash size +# debug.mutex.prof.collisions - number of hash collisions +# debug.mutex.prof.stats - profiling statistics +# +options MUTEX_PROFILING + ##################################################################### # COMPATIBILITY OPTIONS |