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CPULIMIT(1) User commands CPULIMIT(1) NAME cpulimit -- limits the CPU usage of a process SYNOPSIS cpulimit [TARGET] [OPTIONS...] [ -- PROGRAM] DESCRIPTION TARGET must be exactly one of these: -p, --pid=N pid of the process -e, --exe=FILE name of the executable program file -P, --path=PATH absolute path name of the executable program file OPTIONS -b, --background run cpulimit in the background, freeing up the terminal -c, --cpu specify the number of CPU cores available. Usually this is de- tected for us. -l, --limit=N percentage of CPU allowed from 1 up. Usually 1 - 100, but can be higher on multi-core CPUs. (mandatory) -q, --quiet Runs in quiet mode, avoids writing update messages to console. -k, --kill kill target process instead of throttling its CPU usage -r, --restore restore a process killed using the -k flag. -s, --signal send an alternative signal to the watched process when we exit. Default is SIGCONT. -v, --verbose show control statistics -z, --lazy exit if there is no suitable target process, or if it dies -- This is the final CPUlimit option. All following options are for another program we will launch. -h, --help display this help and exit EXAMPLES Assuming you have started `foo --bar` and you find out with top(1) or ps(1) that this process uses all your CPU time you can either # cpulimit -e foo -l 50 limits the CPU usage of the process by acting on the executable program file (note: the argument "--bar" is omitted) # cpulimit -p 1234 -l 50 limits the CPU usage of the process by acting on its PID, as shown by ps(1) # cpulimit -P /usr/bin/foo -l 50 same as -e but uses the absolute path name # /usr/bin/someapp # cpulimit -p $! -l 25 -b Useful for scripts where you want to throttle the last command run. # cpulimit -l 20 firefox Launch Firefox web browser and limit its CPU usage to 20% # cpulimit -l 25 -- firefox -private Launch Firefox web browser in private mode and limit its CPU us- age to 25% # cpulimit -c 2 -p 12345 -l 25 The -c flag sets the number of CPU cores the program thinks are available. Usually this is detected for us, but can be over-rid- den. # cpulimit -l 20 -k firefox Launch the Firefox program and kill it if the process goes over 20% CPU usage. # cpulimit -l 20 -p 1234 -s SIGTERM Throttle process 1234 at 20% CPU usage. If cpulimit is forced to exit, it sends the watched process the SIGTERM signal. NOTES • cpulimit always sends the SIGSTOP and SIGCONT signals to a process, both to verify that it can control it and to limit the average amount of CPU it consumes. This can result in misleading (annoy- ing) job control messages that indicate that the job has been stopped (when actually it was, but immediately restarted). This can also cause issues with interactive shells that detect or other- wise depend on SIGSTOP/SIGCONT. For example, you may place a job in the foreground, only to see it immediately stopped and restarted in the background. (See also <http://bugs.debian.org/558763>.) • When invoked with the -e or -P options, cpulimit looks for any process under /proc with a name that matches the process name argu- ment given. Furthermore, it uses the first instance of the process found. To control a specific instance of a process, use the -p op- tion and provide a PID. • The current version of cpulimit assumes the kernel HZ value 100. AUTHOR This manpage was written for the Debian project by gregor herrmann <gregoa@debian.org> but may be used by others. cpulimit June 2012 CPULIMIT(1)
NAME | SYNOPSIS | DESCRIPTION | EXAMPLES | NOTES | AUTHOR
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