On 22.05.2014 21:04, Etienne wrote:
On 2014-05-22 2:12 PM, Rainer Schuetze wrote:
"NO_INTERIOR" is currently only used for the hash array used by
associative arrays. It is a bit dangerous to use as any pointer,slice or
register still operating on the array is ignored, so collecting it might
corrupt your memory.
That's quite a relief, I was afraid of having to do it ;)
I'm currently exploring the possibility of sampling the pointers during
mark'ing to check if they're gone and using bayesian probabilities to
decide whether or not to skip the pool.
I explained it all here:
https://github.com/D-Programming-Language/druntime/pull/797#issuecomment-43896016
-- paste --
Basically, when marking, you take 1 in X of the references and send them
to a specific array that represents the pool they refer to. Then, next
time you're going to collect you test them individually and if they're
mostly there, you skip marking/free'ing for that particular pool during
collection. You can force collection on certain pools every 1 in X
collections to even out the average lifetime of the references.
You're going to want to have a lower certainty of failure for big
allocations, but basically you're using probabilities to avoid pushing a
lot of useless load on the processor, especially when you're in a part
of an application that's just allocating a lot (sampling will determine
that the software is not in a state of data removal).
http://en.wikipedia.org/wiki/Bayes_factor
-- end paste --
The bayes factor is merely there to choose the appropriate model that
fits with the program. Bayesian inference would take care of deciding if
a pool should end up being mark'ed. In other words, machine learning.
Would you think it'd be a good optimization opportunity?
Hmm, I guess I don't get the idea. You cannot skip a pool based on some
statistics, you might have references in there to anything. As a result
you cannot collect anything.
