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Add more implentation notes based on the comments in sys/conf/NOTES.

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des 2004-01-25 12:30:35 +00:00
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14
share/man/man9/MUTEX_PROFILING.9
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@ -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).