[CHiPPS] Fwd: Questions on Blis

[Alessandro Tiberi]

>> We are running Blis (mpi built) on a single machine with 16Gb Ram and 
>> two quadcore (opteron), so that's a total
>> of eight cores. We tried several  degrees of parallelism (# of process), 
>> from 2 to 8. The bottom line seems to be
>> that the more processes we use, the sooner it runs out of memory. 
>>     
>
> That makes sense, given that CHiPPS is currently architected for a
> distributed environment.  When Ted says that more processes can
> alleviate the memory issue, he is thinking of distributing the processes
> among different nodes in a cluster or grid, each with its own memory.
Yes, that was clear enough.

>> However, from Alp's log, it appears that  relatively few nodes are
>> queued (about 13K nodes with 2 processes running and 7K with 6.)
>> (btw, I have been told that famous commercial software has no problem 
>> with these instances even if running on much lower profile platforms 
>> although I did not personally try
>> it)
>>     
>
> Well, CHiPPS is a development code at this point, so there are bound to
> be lots of opportunities to improve it!
>   
Just to be clear, I think that the work done with CHiPPS is great, the 
comparison  was just to
say that our instaces are not (in some sense) too demanding.

>> I do not have a very strong feeling about this (On the one hand even if 
>> vectors are sparse they eventually are just a sequence of numbers, and 
>> hopefully they are far enough from being uniformly distributed, so we 
>> should gain something from compression...).
>>     
>
> That's likely to be an empirical question, but probably worth a try.
> Writing idle subtrees to disk is also definitely worth a try.
>   
Well, I guess I will eventually try to do both.

Best,

Alessandro