Re: profiling a constructor?

Thanks for all the responses. Yes, I'm looking for the number of allocations of a constructor; this is an allocations issue, not a retention/liveness issue. I'm not concerned about accesses (not even sure what that would mean). Adding this to -ticky would be very helpful -- and not just for me. For example, it would help us to know more precisely why !2249 (implementing BoxedRep) is mired in performance trouble: we could see how many more TyConApp nodes are created. If this would be easy, is there someone who can guide me how to implement it? I am almost as clueless as someone who has never before gazed on GHC's code in these areas. (Or, I would be grateful for someone else to implement it, too.) Thanks, Richard

On May 23, 2020, at 10:11 PM, Simon Peyton Jones wrote:

This would be a sensible thing to be able to count with -ticky. Not hard to add either.

(Richard is asking for number of allocations, not what is live at any moment.)

Simon

| -----Original Message----- | From: ghc-devs On Behalf Of Richard | Eisenberg | Sent: 23 May 2020 13:59 | To: GHC developers | Subject: profiling a constructor? | | Hi devs, | | Is there a way to count the number of times a particular constructor is | allocated? I might want to know, say, the total number of cons cells | allocated over the course of a program, or (in my actual case) the total | number of FunTy cells allocated over the course of a program. | | I can try to do this with an SCC. But it's very clunky: | * The constructor may be used in a number of places; each such place | would need the SCC. | * SCCs can interfere with optimizations. In my use case, this would | negate the usefulness of the exercise entirely, as I think some of the | structures I wish to observe should never come into being, due to | optimizations (e.g. case-of-known-constructor after inlining). | | Surely, the RTS must be able to count the number of times a constructor | is used. But is there any way to access such a feature? If others agree | that this would sometimes be helpful, perhaps we can build the feature. | Now is not the first time I've wanted this. | | Thanks! | Richard | _______________________________________________ | ghc-devs mailing list | ghc-devs@haskell.org | http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs