lockstat(8) - NetBSD Manual Pages

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


NAME

     lockstat -- display kernel locking statistics


SYNOPSIS

     lockstat [-cdeflMmpstx] [-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.

     -d         Disable lockstat.  This is useful when a program crashed leav-
                ing the lockstat kernel driver enabled.

     -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.

     -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 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.

     -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 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 4.0.

NetBSD 9.3                       March 6, 2013                      NetBSD 9.3