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Re: [HTCondor-users] Fractional CPU resources possible?



Hi Carsten,

HTCondor does not currently support fractional CPUs. One potential solution to this is you could lie about the number of CPUs available to the EP so that the CPU cores are actually over committed. I have attached some sample configuration I put together to assist another administrator using this concept.

Cheers,
Cole Bollig

From: HTCondor-users <htcondor-users-bounces@xxxxxxxxxxx> on behalf of Thomas Hartmann <thomas.hartmann@xxxxxxx>
Sent: Monday, June 15, 2026 9:16 AM
To: Carsten Aulbert <carsten.aulbert@xxxxxxxxxx>
Cc: HTCondor-Users Mail List <htcondor-users@xxxxxxxxxxx>
Subject: Re: [HTCondor-users] Fractional CPU resources possible?
 
Hi Carsten,


> Hmm, thus in the slot definition
>
> NUM_SLOTS_TYPE_1 = 1
> SLOT_TYPE_1 @=slot
>   cpus = 16
>   ram = 45%
>   swap = 0%
>   GPUS = auto : Regexp("0000:[04][89CD]:00.0", DevicePciBusId)
> @slot
>
> I would exchange `cpus = 16` by `cpus = 160` and maybe add something like
>
> MODIFY_REQUEST_EXPR_REQUESTCPUS = quantize( RequestCpus *
> IfTheElse( isUndefined(Target.TinyJob), 10.0, 1.0), {1})

yes, I would try something in that direction - but tbh I have not done
it here ð
...but I would expect it to work "in principle" (fingers crossed...)


Thinking about it - maybe instead coming from the slot side, you could
try to tweak the core count and increase it for Condor via something like

NUM_CPUS = $INT($(DETECTED_CPUS) * N)
MEMORY = $(DETECTED_MEMORY)
SLOT_WEIGHT = Cpus * (1.0/N)

(and then on the submitted side some quantization/re-scaling if necessary)

I would be curious how it works out :)

Cheers,
   Thomas


Attachment: dedicated-gpu-pslot.conf
Description: dedicated-gpu-pslot.conf