Re: [HTCondor-users] Help needed understanding cpu core usage with cgroups

[Roderick Johnstone <rmj@xxxxxxxxxxxxx>]

On 13/04/15 20:27, Brian Bockelman wrote:
> > On Apr 13, 2015, at 2:23 PM, Greg Thain <gthain@xxxxxxxxxxx> wrote:
> >
> > On 04/13/2015 01:37 PM, Roderick Johnstone wrote:
> > > Yes, the "foreground (Owner)" are non-condor jobs that are not using cgroups. Our situation is that we use condor to soak up spare cycles on peoples desktops as well as using dedicated computer servers and this was a test of the former situation where I was simulating the workstation owner running their own code outside of condor.
> > >
> > > So, just to double check I understand this, the cgroups is really working to allocate the relative number of cpus between different condor jobs running in different slots according to the request_cpus criterion in the job submit file, regardless of the number of threads running in each job.
> >
> > Right.  To put a finer point on it, the HTcondor cgroup code works to share cpu resources, but only among processes within cgroups that have agreed to share cpus, whether or not those cgroups are managed by HTcondor.
>
> Hi Roderick,
>
> My memory is getting a bit fuzzy on the topic - but isn't the CPU shares mechanism hierarchical?
>
> That is, if you run with BASE_CGROUP=/condor, this is just redistributing the shares given to the /condor group.  Shares given to the other groups are not affected.
>
> Brian

Brian

Yes, that seems to be the way its working.

Roderick