LOCK
The LOCK report is mainly for IBM® service to use when diagnosing performance
problems relating to lock contention. This report shows a detailed
breakdown of how often zFS waits for locks. It also shows which locks
cause the most contention. Additionally, the report monitors how often
a thread sleeps while waiting for an event.
Figure 1 shows an example of a report. Figure 1. Example
of a LOCK report
LOCK:
Locking Statistics
Untimed sleeps: 22 Timed Sleeps: 0 Wakeups: 21
Total waits for locks: 3698
Average lock wait time: 8.261 (msecs)
Total monitored sleeps: 22
Average monitored sleep time: 0.792 (msecs)
Total starved waiters: 0
Total task priority boosts: 0
Top 15 Most Highly Contended Locks
Thread Async Spin
Wait Disp. Resol. Pct. Description
---------- ---------- ---------- ----- --------------
877 0 899 35.763% Log system map lock
1464 0 40 30.285% Anode bitmap allocation handle
481 0 28 10.249% Anode fileset quota lock
291 0 42 6.705% Transaction lock
205 0 62 5.376% Metadata-cache buffer lock
210 0 4 4.309% Anode fileset handle lock
84 68 7 3.201% User file cache main segment lo
0 55 0 1.107% Volser I/O queue lock
38 0 0 0.765% Vnode-cache access lock
2 23 11 0.724% Transaction-cache main lock
19 0 3 0.443% Transaction-cache equivalence c
21 0 0 0.422% Async IO event lock
0 14 0 0.281% Cache Services association main
6 0 0 0.120% Cache Services hashtable resize
0 0 5 0.100% Transaction-cache complete list
Total lock contention of all kinds: 4966
Top 15 Most Common Thread Sleeps
Thread Wait Pct. Description
----------- ------- -----------
22 100.000% Transaction allocation wait
0 0.000% OSI cache item cleanup wait
0 0.000% Directory Cache Buffer Wait
0 0.000% User file cache Page Wait
0 0.000% User file cache File Wait