SC_USAGE
Section: User Commands (1)
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BSD mandoc
Mac OS X
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.
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 it's 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
top(1)
fs_usage1
latency(1)
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- SAMPLE USAGE
-
- SEE ALSO
-
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Time: 04:29:35 GMT, April 24, 2025