Re: [Discuss-gnuradio] 64 bit

[Eric Blossom]

On Fri, Dec 16, 2005 at 03:49:21PM -0500, cswiger wrote:
> Just curious - how much might gnuradio benefit from running
> on 64 bit processors and how much of a rewrite would it take,
> to take full advantage of, say, an Athlon 64 X2, seeing as you
> could theoretically chunk thru twice the data every bus clock?

It already runs on the X86-64, including a first cut at the SSE/3DNow
stuff.  It's what I use everyday, and yes, it is substantially faster!

> I guess the Solaris build doesn't take advantage of the UltraSparc II's.
> A little benchmarking with a 300Mhz processor and a short graph:
> 
>   noise source --> throttle --> low pass filter --> null sink
> 
> using 100Khz sample rate and 67 tap filter uses 80% of one cpu.
> 
> --Chuck

The noise source is pretty expensive, particularly for GR_GAUSSIAN.
Also, you're using the generic fir filter kernel (straight C++).  On
x86 and x86-64 we've got hand-coded assembler for taking advantage of
SSE and 3DNow SIMD instructions.

I don't know if there's a Solaris equivalent to "oprofile" (profiling
using the h/w performance counters), but the first step to making it
faster would be to determine where it's slow.

Eric