[Haskell-cafe] [GHC 7.8.4] IO Monad leak space?

Baojun Wang wangbj at gmail.com
Sat Jul 4 06:17:06 UTC 2015

Appreciate for the prompt reply, sorry for that I assumed the allocations
was caused by space leak. I guess profiling with -auto-all really has huge
impact on allocations. without profiling, haskell version runs about 50%
slower than equivalent C version (both with -O2). Maybe that's  as much as
one could expect.

On Fri, Jul 3, 2015 at 2:41 PM Tom Ellis <
tom-lists-haskell-cafe-2013 at jaguarpaw.co.uk> wrote:

> On Fri, Jul 03, 2015 at 06:00:48PM +0000, Baojun Wang wrote:
> > My concerns is ~80% alloc happens in f3, but both array is allocated by
> > newArray? Since I'm using unboxed array I'm not expecting this kind of
> > laziness.
> I see.  You seem to be asking why it is allocating *at all*.  That's not
> a phenomenon that normally falls under the terminology of "space leak",
> hence my confusion.
> I'm not an expert at reading Core, but I spent some time looking at it
> without seeing anywhere that would obviously allocate a lot.  Eventually I
> decided to supply the profiling options to ghc-core and lo and behold the
> output changed dramatically!
> Unless I am very much misunderstanding how cost centre annotations work,
> the
> amount of allocation without -auto-all is only 10% of the amount with it.
> Please check and let me know if you concur that it is the profiling itself
> that is the root cause of all the allocation!
> Tom
> _______________________________________________
> Haskell-Cafe mailing list
> Haskell-Cafe at haskell.org
> http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.haskell.org/pipermail/haskell-cafe/attachments/20150704/e3dc7d1d/attachment.html>

More information about the Haskell-Cafe mailing list