On 4/30/14, 2:47 PM, John Colvin wrote:
On Wednesday, 30 April 2014 at 20:57:26 UTC, Andrei Alexandrescu wrote:
Finally, immutable is sharable accross thread. That mean, even if we
bypass the type system, that RC must be atomic for immutable.
As they
convert automatically for co,st, that mean that all const code will be
full of atomic increment/decrement. They are bad for the CPU, and cannot
be optimized away.
Good point. I see that as a problem, albeit a solvable one.
How? Having lock; instructions implicitly appearing in normal looking
slice code is unacceptable.
I'm thinking e.g. non-interlocked refcounts go like 1, 3, 5, ... and
interlocked refcounts go like 2, 4, 6, ...
Then you do an unprotected read of the refcount. If it's odd, then it's
impossible to having originated as an interlocked one. So proceed with
simple increment. If it's even, do an interlocked increment.
Andrei
