On Thu, 28 May 2009 12:45:41 -0400, Denis Koroskin <2kor...@gmail.com>
wrote:
On Thu, 28 May 2009 20:32:29 +0400, Andrei Alexandrescu
<seewebsiteforem...@erdani.org> wrote:
BCS wrote:
Everything is indicating that shared memory multi-threading is where
it's all going.
That is correct, just that it's 40 years late. Right now everything is
indicating that things are moving *away* from shared memory.
Andrei
That's true.
For example, we develop for PS3, and its 7 SPU cores have 256KiB of TLS
each (which is as fast as L2 cache) and no direct shared memory access.
Shared memory needs to be requested via asynchronous memcpy requests,
and this scheme doesn't work with OOP well: even after you transfer some
object, its vtbl etc still point to shared memory.
We had hard time re-arranging our data so that object and everything it
owns (and points to) is stored sequencially in a single large block of
memory.
This also resulted in replacing most of the pointers with relative
offsets.
Parallelization is hard, but the result is worth the trouble.
I agree that Andrei's right, but your example is wrong. The Cell's SPU are
a SIMD vector processors, not general CPUs. I also work with vector
processors (NVIDIA's CUDA) but every software/hardware iteration gets
further and further away from pure vector processing. Rumor has it that
the NVIDIA's next chip will be MIMD, instead of SIMD.
