LOCKSTAT(8)						    BSD System Manager's Manual 					       LOCKSTAT(8)

NAME

     lockstat -- display kernel locking statistics

SYNOPSIS

     lockstat [-ceflMmpstx] [-b nbuf] [-E event] [-F func] [-L lock] [-N nlist] [-o file] [-T type] command ...

DESCRIPTION

     The lockstat command enables system wide tracing of kernel lock events, executes the specified 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 lockstat.

     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 default).

     -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 second.  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.

FILES

     /dev/lockstat  lockstat control device
     /dev/ksyms     namelist

EXAMPLES

     # 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

DIAGNOSTICS

     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.

SEE ALSO

     ps(1), systat(1), vmstat(1), iostat(8), pstat(8)

HISTORY

     The lockstat command appeared in NetBSD 4.0.

BSD
								  March 21, 2009							       BSD