Add option to apply a systemd cgroup/slice

[petecallaghan]

No description provided.

[petecallaghan]

https://www.redhat.com/sysadmin/cgroups-part-four?extIdCarryOver=true&sc_cid=701f2000001OH7nAAG

It is possible to include existing services in a new slice (eg music.slice) as follows:

Add a drop in directory for your target service (eg mpd.service): $ mkdir -p /etc/systemd/system/mpd.service.d/

Create a drop in file for that service: $ nano /etc/systemd/system//mpd.service.d/00-slice.conf
[Service] Slice=music.slice CPUAccounting=yes

Assign the shares value: $ systemctl set-property mpd.service CPUShares=1024

Restart:
systemctl daemon-reload
systemctl restart -a mpd.service

[petecallaghan]

However the slice does not seem to get created until after a reboot

[petecallaghan]

More info here: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/resource_management_guide/sec-modifying_control_groups

[petecallaghan]

Question to resolve: how to activate the new slice without a reboot?

[petecallaghan]

This may be linked to the dependencies of mpd.service. Perhaps asking mpd to stop itself might be necessary

[petecallaghan]

sudo service mpd stop
sudo service mpd start

Seems to do the trick

[petecallaghan]

The plug-in configuration should use a slider of 25-75% to identify cpu resource allocation Vs system

[petecallaghan]

Add distinct config for IO and memory as well, controlled by sliders

[petecallaghan]

On further research it is hard to see the benefit of controlling IO or memory, so that will not be part of the plugin.

[petecallaghan]

CPUQuota limits the % of CPU time on a single CPU. This could be useful in ensuring that the shielded processes cannot consume all of a CPU, by setting it to (eg) 95.

This could be controlled by distinct config

[petecallaghan]

CPUShares=value
Replace value with a number of CPU shares. The default value is 1024. By increasing the number, you assign more CPU time to the unit. Setting the value of the CPUShares parameter automatically turns CPUAccounting on in the unit file. Users can thus monitor the usage of the processor with the systemd-cgtop command.