On Monday, 19 June 2017 at 23:39:54 UTC, H. S. Teoh wrote:
On Mon, Jun 19, 2017 at 10:35:42PM +0000, Dmitry Olshansky via
Digitalmars-d wrote:
My take on D's GC problem, also spoiler - I'm going to build a
new one soonish.
http://olshansky.me/gc/runtime/dlang/2017/06/14/inside-d-gc.html
[...]
Very interesting indeed!
One question about killing the no interior pointer attribute:
would this be problematic for 32-bit platforms? And if so, what
do you plan to do about it? Keep the current GC as
version(32bit) and your new version as version(64bit)?
Yeah if said 32-bit application makes use of no interior pointer
attribute then using old gc is an option. I have no plans for
this broken attribute.
One (potentially crazy) idea that occurred to me while reading
your post is TLS allocations. I haven't thought through the
details of how this would interact with the existing language
yet, but would it make sense for some allocations that you know
will never be shared across threads to be allocated in a
thread-local pool instead of the global pool? I.e., in addition
to the global set of memory pools you also have thread-local
memory pools. Then you could potentially run collections
per-thread rather than stop-the-world.
This needs spec updateon interaction between TLS and shared, in
particular the current trend of lock + cast away shared is
problematic. Also the implicit cast to immutable of a result of
unique expression.
On Mon, Jun 19, 2017 at 10:50:05PM +0000, Adam D. Ruppe via
Digitalmars-d wrote:
What is it about Windows that makes you call it a distant
possibility? Is it just that you are unfamiliar with it or is
there some specific OS level feature you plan on needing?
He mentioned the "fork trick", which I assume refers to how
Linux's implementation of fork() uses copy-on-write rather than
immediately duplicating the parent process' memory structures.
There was a D1 GC some time ago that depended on this behaviour
to speed up the collection cycle. AFAIK, Windows does not have
equivalent functionality to this.
To the best of my knowledge all of D's current target OSes
support this save for Windows.
T
