cpulimit -e not catching all processes of that name

[Rob-pw]

Hi!

I'm trying to limit pesky Google Chrome to around 25% CPU since it has a tendency to grind my PC to a halt.

I type 'cpulimit -e chrome -l 25', however it only monitors one process ID for CPU consumption, not all of name 'chrome'.

Many thanks, Rob.

[erm3nda]

Please, read documentation, or at least the HELP display when running just cpulimit with no flag. As i know, Chrome uses a lot of child process to improve stability (they said that, not me).

-e is for put a binary name or path. To include all the process children use -i flag.

Try cpulimit -v -i -e "chrome" -l 25

[PacoH]

I installed cpulimit using brew and none of the 'extra' features work at all. I get Segmentation fault: 11 no matter what I try. The only thing that works is the -p PID option, which makes this no different from cputhrottle. The PID is for the main Google Chrome process, which apparently controls the many many Google Chrome Helper processes.

[erm3nda]

Options totally depends on the distro and the source of the file. I've checked mine (Debian 8 Jessie & cpulimit 2.1) and did worked.

Use it like: for pid in pgrep chrome; do echo $pid && cpulimit -v -b -p "$pid" -l 50 ; done

Also, you can use this Python script https://gist.github.com/erm3nda/ccb8c2b333aa34070a10, wich is the same principle, but simple and direct. The usage is nearly the same, just:

 for pid in `pgrep chrome`; do echo $pid && python cpulimit.py "$pid" ; done

and even with a couple of them, like: pids=pgrep chrome && python cpulimit.py "$pids" but im not sure if this will handle an array or if does need to get a string like python cpulimit.py "1234 12355 12353" so feel free to explore.

I think you'll like more the simple Python than cpulimit. Is not the first time that I see compliants about some features that are only present on some particular (and uknown for me) distros.

On a Centos5 i tried it worked perfectly, but not on all. But, the Python one didn't fail me :-)

Best of luck.

[PacoH]

Thanks for your swift reply. I didn't know about pgrep. It eliminates having to find the PID in the Activity Monitor, so I can automate it. I tried your first approach but it didn't work. I had to use pgrep -o "Google Chrome" to get the oldest, and hence, parent PID. It suffices to limit only the parent process, not the dozens of Google Chrome Helper processes, as your loop would do. So my final script is simply cpulimit -l 0 -v -z -i -p $(pgrep -o "Google Chrome") Works like a charm.

[erm3nda]

There's an important difference between processes and threads, im not sure about.

Also, -l 0 means limit 0% of the current usage, so will not touch it. The -i is also not present in my current install. -z will terminate the running task of cpulimit when the process dies.

You can put it running forever and in background with cpulimit -l 0 -v -b -i -p $(pgrep -o "Google Chrome") as part of your current scripts.

Regards, glad it worked.

[PacoH]

I'm using v0.2 installed by brew on OS X 10.8.5.

Usage: cpulimit [OPTIONS...] TARGET
   OPTIONS
      -l, --limit=N          percentage of cpu allowed from 0 to 1600 (required)
      -v, --verbose          show control statistics
      -z, --lazy             exit if there is no target process, or if it dies
      -i, --include-children limit also the children processes
      -h, --help             display this help and exit
   TARGET must be exactly one of these:
      -p, --pid=N            pid of the process (implies -z)
      -e, --exe=FILE         name of the executable program file or path name
      COMMAND [ARGS]         run this command and limit it (implies -z)

-i limits child processes.

I'm pretty sure that all the Google Chrome Helper processes are child processes, not threads. They each have their own PID.

pgrep "Google Chrome"
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