[jsdl-wg] TileSize and ProcessCount

[Christopher Smith]

Thanks for the clarification Andreas. I guess I need to do some reading up
on some of the changes. :-)

-- Chris


On 1/3/05 18:41, "Andreas Savva" <andreas.savva at jp.fujitsu.com> wrote:

> Hi Chris,
> 
> Just to give you some background on why this is the way it is.
> 
> At the last F2F after a lengthy discussion on topology and what it
> really means the group reached the conclusion that topology is part of
> the application definition rather than part of the hardware
> requirements. (That is, it is independent of the hardware resources to
> be allocated to the job and should be described separately and in terms
> that are not hardware specific.)
> So the topology tags describe the number of processes and their desired
> grouping/tiling and appear in the Application section rather than the
> Resource section. The Resource section (may) contains tags to describe
> the hardware resources required: CPUCount and ResourceCount.
> 
> I have some doubts about the current definition (in particular I think
> we either overloaded the term 'Process' or we defined TileSize the wrong
> way). But I think it is easier to bash this out on a call or f2f (hand
> to hand? :-) at GGF13.
> 
> Andreas
> 
> 
> Christopher Smith wrote:
>> Perhaps there are naming issues here, or there are too many terms defined
>> here. 
>> 
>> JSDL is only concerned with specifying the resource requirements for the
>> allocation request, not with how those resources end up being used (i.e.
>> using threads or processes). So the TileSize indicates how many cpus need to
>> be allocated as a unit within one OS image (i.e. a group of cpus), and the
>> CPUCount would tell you how many cpus are needed in total. I don't believe
>> you need any more. If the job chooses to use processes or threads is
>> independent of the allocation.
>> 
>> So given this example:
>> 
>> 
>>> tasks per job=3
>>> threads per task=4
>>> processors per task=4
>>> 
>> 
>> TileSize = 4
>> CPUCount = 12
>> 
>> This can translate to the PBS syntax "nodes=3:ppn=4" or the LSF syntax "-n
>> 12 -R 'span[ptile=4]'", and I'm sure others as well.
>> 
>> To the entity making the allocation, processes or threads doesn't matter.
>> 
>> -- Chris
>>