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| author | des <des@FreeBSD.org> | 2004-01-25 12:30:35 +0000 |
|---|---|---|
| committer | des <des@FreeBSD.org> | 2004-01-25 12:30:35 +0000 |
| commit | 53ac97ae7500046c5893a70fd0c37dd4f1a807b5 (patch) | |
| tree | 124ade8fe1263b7d8c90bcc9da654f9f09ff06b5 /share | |
| parent | f02f4e8406d62a134af6ba8e6519cdd75e312067 (diff) | |
| download | FreeBSD-src-53ac97ae7500046c5893a70fd0c37dd4f1a807b5.zip FreeBSD-src-53ac97ae7500046c5893a70fd0c37dd4f1a807b5.tar.gz | |
Add more implentation notes based on the comments in sys/conf/NOTES.
Diffstat (limited to 'share')
| -rw-r--r-- | share/man/man9/MUTEX_PROFILING.9 | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/share/man/man9/MUTEX_PROFILING.9 b/share/man/man9/MUTEX_PROFILING.9 index dba35b1..41c13ca 100644 --- a/share/man/man9/MUTEX_PROFILING.9 +++ b/share/man/man9/MUTEX_PROFILING.9 @@ -139,3 +139,17 @@ option increases the size of .Vt struct mtx , so a kernel built with that option will not work with modules built without it. +.Pp +The +.Nm +option also prevents inlining of the mutex code, which results in a +fairly severe performance penalty. +It should therefore only be enabled on systems where mutex profiling +is actually needed. +.Pp +Measurements are made and stored in nanoseconds using +.Xr nanotime 9 , +but are presented in microseconds. +This should still be sufficient for the locks one would be most +interested in profiling (those that are held long and / or acquired +often). |
