Re: [HTCondor-users] How to modify cpus

[Brian Candler <b.candler@xxxxxxxxx>]

On 13/05/2016 14:48, Rich Pieri wrote:
> On 5/13/16 9:08 AM, sjones wrote:
> > # cat /etc/condor/config.d/00-node_parameters
> > NUM_SLOTS = 1
> > SLOT_TYPE_1               = cpus=32,mem=auto,disk=auto
> > NUM_SLOTS_TYPE_1          = 1
> > SLOT_TYPE_1_PARTITIONABLE = TRUE
> >
> > Yet the system continues to run the previous number, cpus=24.
> Try "NUM_CPUS = 32" to override the detected CPU count.
>
> As a rule of thumb, though, you should not allocate more CPUs or cores
> than you actually have. Running two jobs on one core simultaneously will
> take longer for both to complete than running each job sequentially on
> the same core.
That's unless your jobs are doing significant amounts of other activity 
(in particular disk or network I/O), in which case you may need to 
pretend that there are more cores than you really have in order to 
utilise them fully.

Last time I looked at this, I wasn't able to make a job request a 
fraction of a CPU, although it was a while ago since I last tried that.

Also: if a slot advertises one CPU, when a matched job runs I don't 
think it will be prevented from using more than one CPU, unless you are 
using cgroups enforcement.

Regards,

Brian.