How to check CPUs and memory

[Tashrif B.]

Hi all,

After limiting CPUs (and memory), how do I confirm?

I tried `lscpu` and `vmstat -s -S M` within the singularity shell but they both print my host's resources.

Best,
Tashrif

[Thomas Hartmann]

Hi Tashrif,

cgroups don't "virtualize" the resources but the kernel limits the
processes' usage.

For a given process, you can check its cgroups through /proc for example
> /proc/${PID}/cgroup

the current settings are then (on most setups) mounted under
/sys/fs/cgroup/
with the paths from proc below there.

In the 'cpu,cpuacct' sub-group, for example the `cpu.shares` parameter
holds the share of CPU time for this cgroup (relative to the parent group).
Similarly in the `memory` sub-group, an interesting parameter is
`memory.memsw.limit_in_bytes`, which gives the maximum usage of memory
and swap for all the processes in this group.

Cheers,
Thomas

On 15/03/2021 23.07, Tashrif B. wrote:
> Hi all,
>
> After limiting CPUs

> <https://sylabs.io/guides/3.0/user-guide/cgroups.html#limiting-cpu> (and

> memory), how do I confirm?
>
> I tried `lscpu` and `vmstat -s -S M` within the singularity shell but
> they both print my host's resources.
>
> Best,
> Tashrif
>

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