Re: [Condor-users] How to 'dynamically' set the VM_MEMORY macro?

[Rob <spamrefuse@xxxxxxxxx>]

Jason Stowe wrote:
>
> For more information you can see the manual:
> http://www.cs.wisc.edu/condor/manual/v7.2/2_5Submitting_Job.html#2421
> "An example of a job that uses this syntax may be a job that wants to
> know how much memory it can use. The application cannot detect this
> itself, as it would potentially use all of the memory on a multi-slot
> machine. So the job determines the memory per slot, reducing it by 10%
> to account for miscellaneous overhead, and passes this as a command
> line argument to the application. In the submit description file will
> be:
>
> arguments=--memory $$([TARGET.Memory * 0.9]) "
>
> In your case you'll want to use an expression like:
> $$([0.6*(Target.Memory - Target.RESERVED_MEMORY)])


Thank you, but this is not what I want to modify.

When condor starts its processes (master, startd etc.) on the pool PCs,
the value for VM_MEMORY has to bet set to a fixed number; this is the
maximum amount of memory available for a virtual machine.

(I think the arguments-construct allows me to reduce this amount further
in the submit file. But that's not what I want.)

The value of VM_MEMORY defaults to 256 MB, irrespective of the
amount of total physical memory in the pool PC.
And this value is set when the master service starts.

I'd like to set VM_MEMORY to a certain percentage of the total physical
memory in the pool PC, in much the same way as the VM_MAX_NUMBER
defaults to $(NUM_CPUS):

VM_MAX_NUMBER = $(NUM_CPUS)
VM_MEMORY = $(MEMORY) * 0.9

The first line is fine, because the number of CPUs is available as the macro
NUM_CPUS. But the second line fails, because there is apparently no
macro that tells me the total amount of physical RAM in the pool PC.

I'd think: if the number of CPUs is available, then why is not the total
amount of physical RAM???

Thanks!

Rob.