[HTCondor-users] HTCondor/cgroups: limiting CPUs/pinning processes to CPUs with hyperthreaded CPUs

[Thomas Hartmann <thomas.hartmann@xxxxxxx>]

Hi all,

I have a more technical question regarding cgroup support in
HTCondor/cgroups in general.

If a I understand the cgroup documentation correctly, a cgroup cannot be
limited to a "general number of cores" but can only be pinned to certain
cores. I.e., limiting the number of cores for a cgroup means to pin the
cgroup to as many dedicated cores on the system, or?
So, I guess the startd pins a job with core limit correspondingly in a
cgroup to cores, or?

Is this actually a drawback, that processes cannot be switched between
cores (does the CPU would move anyway processes between cores?)?
How does actually a hyperthreaded system would look like - if a process
is pinned to "a hyperthreaded core", I guess the process would be moved
over the physical cores by the CPU, or?

Cheers and thanks,
  Thomas

Attachment: smime.p7s
Description: S/MIME Cryptographic Signature