On Friday, 10 January 2014 at 08:03:03 UTC, Andrei Alexandrescu
wrote:
The design at http://goo.gl/ZVCJeB seems to be a win. It works
well, comprehends all major allocation tropes, someone
implemented a subset of it in C++ and measured good results,
and a coworker is considering adopting the design for a C++
project as well.
An additional feature that I would like to suggest is the concept
of time-limited collection.
The goal would be to be able to write a main loop in my
application where I say:
const auto FRAME_DUR_MS = 25;
while (keepPlaying) {
auto start = Clock.currSystemTick()
update();
render();
GC.collectMsecs( FRAME_DUR_MS - (Clock.currSystemTick() -
start).msecs() );
}
The idea is that the collector, conceptually, has a routine that
it runs. I.e.
1. Point to bottom of stack, scan through.
2. Pop registers from each thread, check values.
3. Determine unreachable values amongst everything allocated.
4. Call destructors on objects.
5. Free memory.
Since "unreachability" is a one-way street, I can pause anywhere
in this process and resume from that location at a later time. I
don't have to go through all of the steps every time I am called.
So while there's no guarantee that any one call to collectMsecs()
actually releases any memory, if the caller continues to call it
reliably, they should be able to keep on top of their memory
usage (or know that they need to allocate less frequently if they
see their memory continue to grow, even under this scheme).
