On 03/22/2010 04:59 PM, Andrei Alexandrescu wrote:
On 03/22/2010 04:03 PM, Andrei Alexandrescu wrote:
On 03/22/2010 03:36 PM, Walter Bright wrote:
Andrei Alexandrescu wrote:
Better suggestions are always welcome. For integrals I'm unclear on
what we could use to make things better. (Clearly we could and should
get rid of the extraneous field.)
Unfortunately, it won't be much of a win. Memory allocation is done in
buckets of size 16, 32, 64, etc. Reducing the node size for a uint[uint]
from 16 to 12 saves no memory at all.
As we discussed, if nodes are allocated in bunches, you could store 5
nodes in a 64-byte block instead of 4. That's more than a 25% increase
in effectiveness because the per-block bookkeeping is also slashed by 5.
Andrei
One more idea before I forget: the bunches approach requires using a
freelist for nodes that are available but not used. (Freelists are a
good idea whether or not bunches are used.)
One good possibility is to store the head of the freelist in a static
variable, such that e.g. all int[string] instances use the same
freelist. And there's no thread contention issue because each thread has
its own freelist.
And the last idea before I forget (just talked to Walter about it) is
that the GC could and should offer functions:
GC.preCollect(void delegate());
GC.postCollect(void delegate());
That way we can effectively implement weak pointers.
Andrei
