Bartosz Milewski Missing post

[Robert Jacques]

On Thu, 28 May 2009 12:45:41 -0400, Denis Koroskin <2korden at gmail.com>  
wrote:

> On Thu, 28 May 2009 20:32:29 +0400, Andrei Alexandrescu  
> <SeeWebsiteForEmail at 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.