impressions on ghc-6.4

[Simon Marlow]

On 09 June 2005 11:47, Serge D. Mechveliani wrote:

> On memory expense
> -----------------
> 
>> A difference of 2.5Mb is really very small.  If you could show that
>> the space usage is linear in one case and flat in another, then we
>> have a problem.
> 
> But a ratio   2600 K / 200 K  for n = 55000  is not so small.
>
> I never tested this, but what if in this mergeSort-like example the
> space sizes are
>                      space.6.4(n) = 13*space.5.02(n)
> 
> (which has the above ratio for n = 55000)
> ?

If you can demonstrate that GHC 6.4 uses 13 times more space than 5.02
on your example, then that's a performance bug - but all you showed so
far is that 6.4 uses 2.5Mb more space.  i.e. you need to do a few more
measurements for different values of n.

Cheers,
	Simon