Limit program CPU usage

[Benjamin-Loison]

For instance I would like to use at most 50% of a single core to avoid Benjamin-Loison/EmbeddedController/issues/6.

I am fine waiting longer for the program to execute.

[Benjamin-Loison]

Would help Benjamin_Loison/baobab/-/issues/8.

[Benjamin-Loison]

DuckDuckGo search Linux limit program CPU usage.

[Benjamin-Loison]

The Ask Ubuntu answer 1367630:

nice --help

Output:

Usage: nice [OPTION] [COMMAND [ARG]...]
Run COMMAND with an adjusted niceness, which affects process scheduling.
With no COMMAND, print the current niceness.  Niceness values range from
-20 (most favorable to the process) to 19 (least favorable to the process).

Mandatory arguments to long options are mandatory for short options too.
  -n, --adjustment=N   add integer N to the niceness (default 10)
      --help        display this help and exit
      --version     output version information and exit

NOTE: your shell may have its own version of nice, which usually supersedes
the version described here.  Please refer to your shell's documentation
for details about the options it supports.

Exit status:
  125  if the nice command itself fails
  126  if COMMAND is found but cannot be invoked
  127  if COMMAND cannot be found
  -    the exit status of COMMAND otherwise

GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/nice>
or available locally via: info '(coreutils) nice invocation'

[Benjamin-Loison]

nice does not seem appropriate if running a single significant process.

[Benjamin-Loison]

Cgroups is for a set of tasks, so not relevant for me.

[Benjamin-Loison]

cpulimit

Output:

Command 'cpulimit' not found, but can be installed with:
sudo apt install cpulimit

seems the most adapted.

[Benjamin-Loison]

apt show cpulimit

Output:

Package: cpulimit
Version: 3.0-1
Priority: optional
Section: universe/admin
Origin: Ubuntu
Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
Original-Maintainer: gregor herrmann <gregoa@debian.org>
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Installed-Size: 49,2 kB
Depends: libc6 (>= 2.34)
Homepage: https://limitcpu.sourceforge.net/
Download-Size: 16,4 kB
APT-Sources: http://archive.ubuntu.com/ubuntu noble/universe amd64 Packages
Description: tool for limiting the CPU usage of a process
 cpulimit is a simple program that attempts to limit the CPU usage of a
 process (expressed in percentage, not in CPU time). This is useful to
 control batch jobs, when you don't want them to eat too much CPU. It does
 not act on the nice value or other priority stuff, but on the real CPU
 usage.  Besides it is able to adapt itself to the overall system load,
 dynamically and quickly.

[Benjamin-Loison]

https://limitcpu.sourceforge.net mentions the fork opsengine/cpulimit has 1.8k stars and last commit was 11 years.

[Benjamin-Loison]

sudo apt install -y cpulimit

Output:

Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following NEW packages will be installed
  cpulimit
0 to upgrade, 1 to newly install, 0 to remove and 2 not to upgrade.
Need to get 16,4 kB of archives.
After this operation, 49,2 kB of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu noble/universe amd64 cpulimit amd64 3.0-1 [16,4 kB]
Fetched 16,4 kB in 0s (223 kB/s)     
Selecting previously unselected package cpulimit.
(Reading database ... 995231 files and directories currently installed.)
Preparing to unpack .../cpulimit_3.0-1_amd64.deb ...
Unpacking cpulimit (3.0-1) ...
Setting up cpulimit (3.0-1) ...
Processing triggers for man-db (2.12.0-4build2) ...

[Benjamin-Loison]

cpulimit --help

Output:

CPUlimit version 3.0
Usage: cpulimit TARGET [OPTIONS...] [-- PROGRAM]
   TARGET must be exactly one of these:
      -p, --pid=N        pid of the process
      -e, --exe=FILE     name of the executable program file
                         The -e option only works when
                         cpulimit is run with admin rights.
      -P, --path=PATH    absolute path name of the
                         executable program file
   OPTIONS
      -b  --background   run in background
      -f  --foreground   launch target process in foreground and wait for it to exit
      -c  --cpu=N        override the detection of CPUs on the machine.
      -l, --limit=N      percentage of cpu allowed from 1 up.
                         Usually 1 - 1600, but can be higher
                         on multi-core CPUs (mandatory)
      -m, --monitor-forks  Watch children/forks of the target process
      -q, --quiet        run in quiet mode (only print errors).
      -k, --kill         kill processes going over their limit
                         instead of just throttling them.
      -r, --restore      Restore processes after they have
                         been killed. Works with the -k flag.
      -s, --signal=SIG   Send this signal to the watched process when cpulimit exits.
                         Signal should be specificed as a number or 
                         SIGTERM, SIGCONT, SIGSTOP, etc. SIGCONT is the default.
      -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

benjamin_loison@benjamin-loison-framework:~/my_test$ cpulimit --limit 10 ./target/debug/my_test
benjamin_loison@benjamin-loison-framework:~/my_test$ Process 65854 detected
^C
benjamin_loison@benjamin-loison-framework:~/my_test$ 

consume at most about 15% contrarily to previous 100%.

Well it does not hang, so it keeps running on ctrl + c.

[Benjamin-Loison]

src/main.rs:

fn main() {
    loop {}
}

[Benjamin-Loison]

benjamin_loison@benjamin-loison-framework:~/my_test$ cpulimit --foreground --limit 10 ./target/debug/my_test
Process 66224 detected
^CExiting...
benjamin_loison@benjamin-loison-framework:~/my_test$ 

works as wanted.

[Benjamin-Loison]

cpulimit --foreground --limit 10 sudo whoami

Output:

Process 66278 detected
root

cpulimit --foreground --limit 10 sudo ./target/debug/my_test

Process 66357 detected

ctrl + c was not working I had to sudo killall my_test in another terminal.

[Benjamin-Loison]

benjamin_loison@benjamin-loison-framework:~/my_test$ sudo cpulimit --foreground --limit 10 ./target/debug/my_test
Process 66505 detected
^CExiting...
benjamin_loison@benjamin-loison-framework:~/my_test$ 

works as wanted.

[Benjamin-Loison]

As I don't know how much I am fine consuming the CPU, being able to adapt while the program is running would be nice.

For gdu using multiple cores, it seems that the CPU limit applies to each core independently.