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LOCKSTAT(8) BSD System Manager's Manual LOCKSTAT(8)
lockstat -- display kernel locking statistics
lockstat [-ceflMmpstx] [-b nbuf] [-E event] [-F func] [-L lock] [-N nlist] [-o file]
[-T type] command ...
The lockstat command enables system wide tracing of kernel lock events, executes the speci-
fied command, and when finished reports statistics to the user.
Tracing may be ended early by sending SIGINT (Ctrl-C) to the process being executed by lock-
The lockstat pseudo-device driver must be present in the kernel, and the lockstat command
may only be used by the root user.
The options are as follows:
-b nbuf Adjust the number of trace buffers allocated by the kernel to nbuf.
-c Report percentage of total events by count, and sort the output by number of
events. The default is to key on event timings.
-E event Limit tracing to one type of event. Use the -e option to list valid events.
-e List valid event types for the -E option and exit.
-F func Limit tracing to locking operations performed within the specified function.
func must be the name of a valid function in the kernel.
-f Trace only by calling functions; do not report on individual locks.
-L lock Limit tracing to one lock. lock may either be the name of a lock object in the
kernel, or a kernel virtual address.
-l Trace only by lock; do not report on calling functions.
-M Merge lock addresses within unique objects.
-m Merge call sites within unique functions.
-N nlist Extract symbol information from the nlist file.
-o file Send output to the file named by file, instead of the standard output (the
-p Show the average number of events and time spent per CPU. The default is to show
the total values. May be used in conjunction with the -s option.
-s Show the average number of events per second, and the average time spent per sec-
ond. The default is to show the total values.
-T type Limit tracing to one type of lock. Use the -t option to list valid lock types.
-t List valid lock types for the -T option and exit.
-x Summarize events, and do not report on lock types.
/dev/lockstat lockstat control device
# lockstat -L uvm_pageqlock sleep 10
Elapsed time: 10.01 seconds.
-- Adaptive mutex spin
Total% Count Time/ms Lock Caller
------ ------- --------- ---------------------- ------------------------------
100.00 1281 0.78 uvm_pageqlock <all>
39.81 385 0.31 uvm_pageqlock uvm_fault_internal+11cc
30.98 358 0.24 uvm_pageqlock uvm_fault_internal+bb1
28.06 522 0.22 uvm_pageqlock uvm_anfree+132
0.51 5 0.00 uvm_pageqlock ubc_fault+28f
0.20 4 0.00 uvm_pageqlock uvm_fault_internal+12b6
0.18 2 0.00 uvm_pageqlock uao_detach_locked+58
0.11 2 0.00 uvm_pageqlock uvm_fault_internal+7d5
0.08 2 0.00 uvm_pageqlock ufs_balloc_range+160
0.07 1 0.00 uvm_pageqlock uvm_fault_internal+107b
lockstat: incompatible lockstat interface version
The kernel device driver does not match the version of the lockstat command.
lockstat: overflowed available kernel trace buffers
Increase the number of buffers using the -b option.
lockstat: ioctl: Invalid argument
The number of trace buffers is outside the minimum and maximum bounds set by the kernel.
ps(1), systat(1), vmstat(1), iostat(8), pstat(8)
The lockstat command appeared in NetBSD 4.0.
BSD March 21, 2009 BSD
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