SC_USAGE(1) BSD General Commands Manual SC_USAGE(1)NAMEsc_usage — show system call usage statistics
SYNOPSISsc_usage [-c codefile] [-e] [-l] [-s interval] pid | cmd | -E execute
DESCRIPTIONsc_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
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
SAMPLE USAGEsc_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 ALSOfs_usage(1), latency(1), top(1)Mac OS X October 28, 2002 Mac OS X