Performance week 25/6-29/6

Simon Marlow simonmar at
Mon Jul 25 06:33:49 EDT 2005

On 25 July 2005 10:07, Ketil Malde wrote:

> "Simon Marlow" <simonmar at> writes:
>> We're interested in performance issues with both GHC itself and
>> GHC-compiled code.
> I can think of a couple of things.
> One is the performance of Int64 (which unsurprisingly is inferior to
> Int(32) but more surprisingly, also to Integer).  I've reported it
> previously, but can dig it up again, if desired.

Added to the list, thanks.

> The other is probably not as relevant, but I'll mention it anyway.  I
> occasionally use rather large arrays, and UArrays can save a
> considerable amount of space.  Sometimes, however, I want to store
> more complex structures than those UArrays are provided for.  It seems
> to me that what I really want are *strict* arrays (which the compiler
> then can unbox automatically), and that these could be provided for
> any (single constructor) data type?

Manuel Chakravarty's flattened arrays are what you want; I'm not sure of
the implementation status though.  Also, once we have associated types
it will be easier to do this (see the associated types paper for an


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