love for hpc?

Simon Marlow marlowsd at
Wed Nov 13 10:29:46 UTC 2013

On 07/11/13 05:03, Evan Laforge wrote:
> Is anyone out there using HPC?  It seems like it was gotten into a
> more or less working if not ideal state, and then abandoned.
> Things I've noticed lately:
> The GHC runtime just quits on the spot if there's already a tix file.
> This bit me when I was parallelizing tests.  It's also completely
> unsafe when run concurrently, mostly it just overwrites the file,
> sometimes it quits.  Sure to cause headaches for someone trying to
> parallelize tests.
> You can't change the name of the output tix file, so I worked around
> by hardlinking the binary to a bunch of new ones, and then doing 'hpc
> sum' on the results.
> The hpc command is super slow.  It might have to do with it doing its
> parsing with Prelude's 'read', and it certainly doesn't help the error
> msgs.
> And the whole thing is generally minimally documented.
> I can already predict the answer will be "yes, HPC could use some
> love, roll up your sleeves and welcome!"  It does look like it could
> be improved a lot with just a bit of effort, but that would be a yak
> too far for me, at the moment.  I'm presently just curious if anyone
> else out there is using it, and if they feel like it could do with a
> bit of polishing.

I think the core functionality of HPC is working pretty well, I gave it 
an overhaul when I combined the internal mechanisms used by HPC, 
Profiling and the GHCi debugger.  The surrounding tooling and 
documentation, as you say, could do with some love.

I think this would be a great way for someone to get involved with GHC 
development, because for the most part it's not deep technology, and 
there are lots of small improvements to make.  A good way to start would 
be to create some feature-request tickets describing some improvements 
that could be made.


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