I haven't been watching this, but I have one question: does prefetching actually *work*? Do you have benchmarks (or better still, actual library/application code) that show some improvement? I admit to being slightly sceptical - when I've tried using prefetching in the GC it has always been a struggle to get something that shows an improvement, and even when I get things tuned on one machine it typically makes things slower on a different processor. And that's in the GC, doing it at the Haskell level should be even harder. Cheers, Simon On 22/11/2014 05:43, Carter Schonwald wrote:
Hey Everyone, in https://ghc.haskell.org/trac/ghc/ticket/9353 and https://phabricator.haskell.org/D350
is some preliminary work to fix up how the pure versions of the prefetch primops work is laid out and prototyped.
However, while it nominally fixes up some of the problems with how the current pure prefetch apis are fundamentally borken, the simple design in D350 isn't quite ideal, and i sketch out some other ideas in the associated ticket #9353
I'd like to make sure pure prefetch in 7.10 is slightly less broken than in 7.8, but either way, its pretty clear that working out the right fixed up design wont happen till 7.12. Ie, whatever makes 7.10, there WILL have to be breaking changes to fix those primops for 7.12
thanks and any feedback / thoughts appreciated -Carter
_______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://www.haskell.org/mailman/listinfo/ghc-devs