---
name: "sc_usage"
section: "1"
platform: "macos"
package: "system_cmds"
version: "1042.120.1"
release: "macOS 26.5"
platforms: ["macos"]
url: "https://new.carta.tech/sc_usage"
---

# sc\_usage(1)

show system call usage statistics

## 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)](/fs_usage/1.md), [latency(1)](/latency/1.md), [top(1)](/top/1.md)