Re: [Condor-users] suspending jobs - resourse efficiency questions

[Dan Bradley <dan@xxxxxxxxxxxx>]

Burak Han Alver wrote:

> Hi,
>
> I have questions about suspending condor jobs in favor of other condor 
> jobs with configuration similar to the way described in 3.5.10.6
> http://www.cs.wisc.edu/condor/manual/v6.8/3_5Startd_Policy.html#SECTION004510600000000000000
>
> Do I understand correctly that:
> 1. The suspended job still uses memory and the running job will need to 
> use less memory in principle?
>  

The suspended job uses virtual memory, but not necessarily physical 
RAM.  If the computer is configured to provide extra virtual memory on a 
disk (aka swap space), then the operating system will likely move the 
suspended job to disk if there is demand for its space in RAM.

> 2. The suspended job will not use CPU and the running job will be able 
> to use all of the CPU even though two virtual machines are defined?
>  
Yes.

> 3. Even though the whole CPU is available, the ClassAd for the VM will 
> advertise half the computing power?
>  
Condor will advertise twice as much computing power as actually exists 
(because in this example policy, NUM_CPUS is set twice the actualy 
number of CPUs).  However, the suspension policy ensures that only one 
job runs on the real CPU at a time.

--Dan