On 4/18/2014 10:53 AM, Andrei Alexandrescu wrote:
On 4/18/14, 10:12 AM, Walter Bright wrote:
On 4/18/2014 8:34 AM, Andrei Alexandrescu wrote:
Well there's been work on that. I mentioned this recent paper in this
group:
http://goo.gl/tavC1M, which claims RC backed by a cycle collector can
reach
parity with tracing. Worth a close read.
A couple crucial points:
1. It achieves near parity with tracing, i.e. with a regular GC. It says
nothing about performance for regular pointer code, when those pointers
are replaced with ref counts.
This is moving the goalposts. "Regular pointer code" is unsafe, and safety has
been part of your past arguments. This is tracing GC compared to refcounting,
cut and dried.
It applies equally to D arrays. Take a look at optimized array loops in D - the
generated code is as good as C++ pointer style.
2. It's a Java VM implementation. You can bet that the VM internally
isn't using ref counting - too slow.
Not sure what this means in context.
Dogfood.
3. I picked a GC for D because a GC coexists peacefully with pointers of
all types. This is not remotely true with ref counting. It's not an
issue with Java, which has no pointers, but this coexistence problem
would be a huge one for D.
Agreed.
Phew! That's a fundamental point, and I'm glad we agree on it.
