{{tag>Brouillon Ressources cgroups}}

= Limiter les ressources CPU pour un process donne

Restreindre l'usage de CPU 

How to limit CPU Usage of a process

Voir :
* https://wiki.archlinux.org/index.php/cgroups
* https://linuxfr.org/users/zezinho/journaux/les-cgroups-un-outil-trop-meconnu
* https://linuxhint.com/limit_cpu_usage_process_linux/

<code bash>
nice -n 19 COMMAND
</code>
ou
<code bash>
renice +19 1234
#ionice -c3 -p 1234
</code>

Ou encode
<code bash>
systemd-run -p IOWeight=10 updatedb
</code>

Exemple
<code bash>
# best effort, highest priority
sudo ionice -c2 -n0 -p `pgrep etcd`
</code>

<code bash>
cgcreate -g cpu:/cpulimit
cgset -r cpu.cfs_period_us=1000000 cpulimit
cgset -r cpu.cfs_quota_us=100000 cpulimit
</code>

check
<code bash>
cgget -g cpu:cpulimit
</code>

<code bash>
cgexec -g cpu:cpulimit COMMAND
</code>

ou
<code bash>
echo 1234 > /sys/fs/cgroup/cpu/cpulimit/tasks
</code>

ou
<code bash>
#cpulimit -p <PID> -l <%CPU>
cpulimit -p 1234 -l 80
</code>

== Pb 

=== write error: No space left on device

Erreur 
<code ->
# echo 1234 > /sys/fs/cgroup/cpuset/cpulimit/tasks
-bash: echo: write error: No space left on device
</code>

Solution
<code bash>
echo 0 > /sys/fs/cgroup/cpuset/cpulimit/cpuset.mems 
echo 0 > /sys/fs/cgroup/cpuset/cpulimit/cpuset.cpu
</code>



== How to limit a process to one CPU core in Linux - CPU affinity

start a command with the given affinity
<code bash>
taskset -c 0 mycommand --option
</code>

set the affinity of a running process
<code bash>
taskset -c -pa 0 1234
</code>