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sc_usage(1)               BSD General Commands Manual              sc_usage(1)


NAME

     sc_usage -- show system call usage statistics


SYNOPSIS

     sc_usage [-c codefile] [-e] [-l] [-s interval] pid | cmd | -E execute


DESCRIPTION

     sc_usage displays an ongoing sample of system call and page fault usage
     statistics for a given process in a ``top-like'' fashion.  It requires
     root privileges due to the kernel tracing facility it uses to operate.

     Page faults can be of the following types:
     PAGE_IN     page had to read from disk
     ZERO_FILL   page was created and zero filled
     COW         page was copied from another page
     CACHE_HIT   page was found in the cache

     The arguments are as follows:

     -c      When the -c option is specified, it expects a path to a codefile
             that contains the mappings for the system calls.  This option
             overrides the default location of the system call codefile which
             is found in /usr/share/misc/trace.codes.

     -e      Specifying the -e option generates output that is sorted by call
             count.  This overrides the default sort by time.

     -l      The -l option causes sc_usage to turn off its continuous window
             updating style of output and instead output as a continuous
             scrolling of data.

     -s      By default, sc_usage updates its output at one second intervals.
             This sampling interval may be changed by specifying the -s
             option.  Enter the interval in seconds.

     pid | cmd | -E execute
             The last argument must be a process id, a running command name,
             or using the -E option, an execution path followed by optional
             arguments.  The system call usage data for the process or command
             is displayed.  If the -E flag is used, sc_usage will launch the
             executable, pass along any optional arguments and display system
             call usage date for that executable.

     The data columns displayed are as follows:

     TYPE                      the system call type
     NUMBER                    the system call count
     CPU_TIME                  the amount of cpu time consumed
     WAIT_TIME                 the absolute time the process is waiting
     CURRENT_TYPE              the current system call type
     LAST_PATHNAME_WAITED_FOR  for each active thread, the last pathname that
                               was referenced by a system call that blocked
     CUR_WAIT_TIME             the cumulative time that a thread has been
                               blocked
     THRD#                     the thread number
     PRI                       current scheduling priority

     The sc_usage command also displays some global state in the first few
     lines of output, including the number of preemptions, context switches,
     threads, faults and system calls, found during the sampling period.  The
     current time and the elapsed time that the command has been running is
     also displayed here.  The sc_usage command is also SIGWINCH savvy, so
     adjusting your window geometry may change the list of system calls being
     displayed.  Typing a `q' will cause sc_usage to exit immediately.  Typing
     any other character will cause sc_usage to reset its counters and the
     display.


SAMPLE USAGE

     sc_usage Finder -e -s2

     sc_usage will sort the Finder process usage data according to system call
     count and update the output at 2 second intervals.


SEE ALSO

     fs_usage(1), latency(1), top(1)

Mac OS X                       October 28, 2002                       Mac OS X

Mac OS X 10.6 - Generated Thu Sep 17 20:09:06 CDT 2009
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