FYI, a new 'lockstat' command tarball is available:
http://oss.sgi.com/projects/lockmeter/download/lockstat-1.4.5.tar.gz
Some differences from the previous version:
1) Many output fields are narrower, e.g., using fewer digits to the
right of a decimal point.
2) The TOTAL lock usage field remains as an integer count, but the
NOWAIT, SPIN, and REJECT fields are now percentages of the TOTAL, rather
than simple counters. Not only does this consume fewer output columns,
but I believe it improves comprehension when the counts are high (since
the numeric outputs weren't pretty-printed with commas).
3) A new WAIT field is added to the existing MEAN and MAX hold times:
"%CPU". This value reports the percentage of available CPU cycles that
are being consumed by waiting on a lock. This turns out to be a very
useful way to identify important hot locks. The CON (CONtention) field
identifies the percentage of time that an attempt to acquire a lock
finds the lock already owned. While this CON value is interesting, you
previously had to multiply the SPIN value (the number of actual WAITs)
by the mean wait-time, then divide by the length of the sampling time
and divide by the number of CPUs, in order to understand exactly how
detrimental the contention was. Now this calculation is done for you.
And, as previously stated, the Lockmeter kernel patch is available
against 2.4.2, 2.4.1, and 2.4.0 sources.
Enjoy!
John Hawkes
hawkes@xxxxxxxxxxxx
|