On Mon, Aug 15, 2005 at 15:59:34 +0100, Adrian Howard wrote: > On 15 Aug 2005, at 13:17, Yuval Kogman wrote:
> I'm not sure what you're proposing here. A separate arena for
> stuff you want to allocate and not be moved by the GC? How would
> I tell the compiler?
You won't, the language glue is responsible for setting that up for
you, and it does that by assuming it's always there, and the
compiler simply optimizes the cases where it's never going to be
needed.
> How about
>
> do : GC::priority(:new) {
> # only GC things allocated during the lifetime
> # of the block
> }
I think that's not "priority" but "limit" or "scoped" or
"origin(:local)" or something like that...
Let's define some terms:
scope/origin - where objects are created
priority - how important is it that garbage is collected
(high priority == more cpu use, less ram use)
delay - pauses in the main flow that have nothing to do with
priority. No delay could mean less performaance, but more
responsiveness. Applicable to event loops and such.
timelyness - the property of an object such that it's
finalization subroutine is called the moment it becomes
unreachable. This is important for objects using finalizers for
resource management, especially when an unreleased resource
could cause deadlock.
finalization - the act of calling an object's finalize
subroutine, and the release of it's memory.
The aspects of control we need:
scope - which objects get cleaned up
priority - what performance tradeoffs we want to make
delay - whether or not the normal program flow will ever be
paused when it is known that no timely objects need to be
destroyed. Also possibly the maximum amount of time (in
milliseconds?) that a GC iteration may take.
timelyness - whether all objects, some objects (That are marked
using 'but' or by their class), or no objects should be checked
for timely destruction
finalization - whether objects should be cleaned up at all
> Actually, since to my naive eyes it looks like the GC is a first
> class object the problem can probably be solver better by adding
> your own.
Well, as I see it the GC is a subobject of the runtime. The amount
of control that this object can give you can be checked using the
strong support for reflection that perl 6 will have, or by simply
asking the runtime to switch GC (if it lets you do that).
--
() Yuval Kogman <[EMAIL PROTECTED]> 0xEBD27418 perl hacker &
/\ kung foo master: uhm, no, I think I'll sit this one out..: neeyah!
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