Re: [Condor-users] RAM allocated to dynamic slots

[Erik Erlandson <eje@xxxxxxxxxx>]

On Mon, 2012-07-30 at 15:22 +0100, Brian Candler wrote:
> I wonder if someone can explain the following to me.  I am just getting
> started with partitioned slots, but I find that if I submit jobs with
> RequestMemory = 1991 then the apparent memory allocated for the slot is 2688
> (which is 35% higher than I requested)

Hi Brian,

it looks like you are seeing the effects of the default value for
MODIFY_REQUEST_EXPR_REQUESTMEMORY:

MODIFY_REQUEST_EXPR_REQUESTMEMORY =
quantize(RequestMemory,{TotalSlotMemory / TotalSlotCpus / 4})

Documentation is here:
http://research.cs.wisc.edu/condor/manual/v7.8/3_3Configuration.html#18487





> 
> $ condor_status
> 
> Name               OpSys      Arch   State     Activity LoadAv Mem   ActvtyTime
> 
> slot1@dev-storage1 LINUX      X86_64 Unclaimed Idle     1.000  1792  0+00:04:42
> slot1_1@dev-storag LINUX      X86_64 Claimed   Busy     1.010  2688  0+00:03:00
> slot1_2@dev-storag LINUX      X86_64 Claimed   Suspende 1.910  2688  0+00:00:04
> slot1@dev-storage2 LINUX      X86_64 Unclaimed Idle     1.000  1792  0+00:04:42
> slot1_1@dev-storag LINUX      X86_64 Claimed   Busy     0.940  2688  0+00:03:31
> slot1_2@dev-storag LINUX      X86_64 Claimed   Busy     1.440  2688  0+00:03:29
>                      Total Owner Claimed Unclaimed Matched Preempting Backfill
>         X86_64/LINUX     6     0       4         2       0          0        0
>                Total     6     0       4         2       0          0        0
> 
> The slots are defined as follows in /home/condor/condor_config.local:
> 
> # On dev-storage1: a 2-core CPU with hyperthreading, 8GB RAM
> SLOT_TYPE_1 = cpus=2, ram=90%, swap=100%, disk=100%
> SLOT_TYPE_1_PARTITIONABLE = True
> NUM_SLOTS_TYPE_1 = 1
> 
> # On dev-storage2: a 4-core CPU without hyperthreading, 8GB RAM
> SLOT_TYPE_1 = cpus=4, ram=90%, swap=100%, disk=100%
> SLOT_TYPE_1_PARTITIONABLE = True
> NUM_SLOTS_TYPE_1 = 1
> 
> Now, if I retry with the job having RequestMemory = 750 I get an apparent
> Mem used in the dynamic slot of 896, which is only a 20% premium. 
> condor_status -long also shows Memory=896 and TotalSlotMemory=896 for the
> used dynamic slots.
> 
> Is Condor over-estimating the declared memory usage on purpose? If so, where
> can I look to tweak this down a bit?
> 
> Thanks,
> 
> Brian.
> 
> P.S. In the partitionable slots I see
>   TotalMemory = 7965
>   TotalSlotMemory = 7168
> which correctly reflects the "ram=90%" for the slot.
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