lockstat(8) - NetBSD Manual Pages

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


NAME

     lockstat -- display kernel locking statistics


SYNOPSIS

     lockstat [-celpst] [-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 out-
                put by number of events.  The default is to key on event tim-
                ings.

     -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 spec-
                ified function.  func must be the name of a valid function in
                the kernel.

     -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.

     -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 conjunc-
                tion 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 val-
                ues.

     -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.


FILES

     /dev/lockstat  lockstat control device
     /dev/ksyms     default namelist
     /netbsd        namelist


EXAMPLES

     # lockstat sleep 10
     Elapsed time: 10.02s

     -- Spin mutex spin

     Total%  Count   Time/ms       Lock                  Caller
     ------ ------- --------- -------------- -------------------------------
     100.00    1576     44.27 kernel_mutex   <all>
      95.71    1493     42.46 kernel_mutex   _kernel_lock+0xd1
       4.29      82      1.80 kernel_mutex   _kernel_lock_acquire_count+0xb0


DIAGNOSTICS

     lockstat: incompatible lockstat interface version

     The kernel device driver does not match the version of the lockstat com-
     mand.

     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 5.0.

NetBSD 4.0                     September 1, 2006                    NetBSD 4.0