Re: Retainer profiling -- too slow?

Tim Chevalier wrote:

Hi all,

Are there any known problems with retainer profiling in GHC 6.8.2? I have a program that takes 3 minutes to run with "normal" profiling enabled (+RTS -P -RTS), but with +RTS -P -hr -RTS, it's 20 minutes and counting. I can tell that progress is being made since the .hp file keeps getting bigger, but that seems like a lot of overhead.

I can try to come up with a smaller test case if necessary; just wanted to see if there's any known problem.

It certainly is slow, especially with large heaps, because IIRC it has to do multiple traversals of the heap. The +RTS -sstderr output will tell you how much time is spent doing retainer profiling. (also retainer profiling is often not terribly useful IMO). Cheers, Simon