parallel cost-centre profiling

[Simon Marlow]

On 15/06/2010 16:28, Henrique Ferreiro wrote:

> I got the most important pieces working (I think). The question now
> is, are you interested in this?

It all depends on whether other people would find it useful or not.  At 
the moment I'm not convinced that profiling each Capability separately 
will give results that are useful, because the assignment of work to 
Capabilities is quite arbitrary and will change from run to run.  The 
only way to get meaningful results would be to use forkOnIO; this won't 
be very useful for par/pseq or Strategies.

So the question really is: what information do you want out?  I can see 
a use for just doing ordinary profiling on parallel programs, although 
the overheads of profiling may well get in the way of getting useful 
information out.

One thing you could do is to use HPC for profiling.  The idea would be 
to record the last tick, and sample the thread/tick at each interval. 
Then you get a per-thread profile, but without the stack information of 
the cost-centre profiler.  Perhaps the overhead of this might be too 
high though.

Cheers,
	Simon