Re: [Discuss-gnuradio] ps3 performance

[Eric Blossom]

On Tue, Oct 30, 2007 at 09:44:39AM +0200, Juha Vierinen wrote:
> BTW, terrasoft sells ps3 pre-installed with linux (and a root password
> supplied). I have never even connected a monitor to my ps3.
> 
> But as to performance, has anyone measured decent performance on a
> ps3? I am starting to think that it is not possible to achieve
> anything near the theoretical peak performance. I am often getting
> better performance with a intel core2 than on the 6+1 processors that
> come with Cell. Intel c compiler often comes up with a faster program
> just by autovectorizing a standard c program --  and this is compared
> to something hand vectorized and paralellized for Cell. It could be
> just that I'm not at all good at optimizing code, but this is also
> true for some of the examples that come with the IBM SDK (eg. the
> euler solver). The only thing that I have found to be impressive was
> the cell optimized fft.

(1) Are you ordering and aligning your SPE instructions such that you're
    getting dual issue?

(2) Are you providing branch hints?  A mispredicted branch stalls for
    11 cycles.

Eric