[Beowulf] Opinions of Hyper-threading?
m.janssens at opencfd.co.uk
Thu Feb 28 10:09:12 PST 2008
How do your Rate numbers correlate to the max bandwitdh of 32GB/s
Or do these threads all operate on the same data?
On Thursday 28 February 2008 08:38, John Hearns wrote:
> On Wed, 2008-02-27 at 23:30 -0800, Bill Broadley wrote:
> > I don't see any particular reason why memory bandwidth can go through a
> > full doublings in the near future if there was a market for it, last I
> > checked nvidia was doing pretty well ;-)
> >  Sorry to use marketing bandwidth, I've not seen stream numbers for
> > CUDA yet. I hope to work on one though. If anyone has numbers please
> > speak up.
> Some numbers here:
> Running this on my 8600 card I get:
> STREAM Benchmark implementation in CUDA
> Array size (single precision)=2000000
> using 128 threads per block, 15625 blocks
> Function Rate (MB/s) Avg time Min time Max time
> Copy: 291777.6696 0.0001 0.0001 0.0001
> Scale: 291777.6696 0.0001 0.0001 0.0001
> Add: 437666.5043 0.0001 0.0001 0.0001
> Triad: 437666.5043 0.0001 0.0001 0.0001
> All the 0.0001 don't look right to me, but its 8:30 here and I should
> get on with the day job.
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