Unified heap

[Kostis Sagonas]

Francesco Cesarini wrote:

 > When looking at the unified heap, one of my major worries is memory
 > fragmentation. Due to past experience (Jam 1998) after having run
 > heavy duty programs for a long period of time, I am scared it is
 > bound to happen.

You should explain to us a bit more why you are worried about memory
fragmentation in the unified heap model, especially since (at least
in theory) one of the arguments "pro" unified heap is that of lower
fragmentation.  The reason is that with the unified heap model, the
whole memory is available to any process that needs it: either
immediately if there is free space, or after GC.  In the current
memory model, a process cannot allocate in the heap of another
process even if that heap contains a large area of unused space.

 > Has the Hipe team looked into this?  Have you any theories or done
 > any measurements?

For theories, see above.  For measurements, we are currently conducting
them, so if you have a program that supports your worries, please do
send it to us. 

Cheers,

Kostis.