On Tuesday, 15 July 2014 at 21:13:22 UTC, Paulo Pinto wrote:
Am 15.07.2014 22:58, schrieb deadalnix:
On Tuesday, 15 July 2014 at 20:03:15 UTC, Chris wrote:
From the link above:
"It’s a common but false belief that reference counting
(using shared
pointers in particular) is better than garbage collection.
There is
actual research* showing that the two approaches are just two
sides of
the same coin. You should realize that deleting a shared
pointer may
lead to an arbitrary long pause in program execution, with
similar
performance characteristics as a garbage sweep. It’s not only
because
every serious reference counting algorithm must be able to
deal with
cycles, but also because every time a reference count goes to
zero on
a piece of data a whole graph of pointers reachable from that
object
has to be traversed. A data structure built with shared
pointers might
take a long time to delete and, except for simple cases,
you’ll never
know which shared pointer will go out of scope last and
trigger it."
* http://www.cs.virginia.edu/~cs415/reading/bacon-garbage.pdf
Yes but D's GC is crap. I actually wanted to a a quick hack in
it
recently to avoid going through the lock every time for every
operation, but ended up giving up. Also the API between the GC
and the compiler need to be reworked.
Which boils down to having to improve the GC implementation,
not that GC in general is bad.
Perhaps we should stop calling it a "Garbage Collector" and call
it "Fully Lazy Snapshot Reference Counting" instead :)
