Re: Roadrunner Supercomputer using 12,960 CELL Processors Hits 1

On Jun 11, 6:10 pm, Robert Myers <rbmyers...@[EMAIL PROTECTED]
> wrote:
> On Jun 11, 5:22 am, already5cho...@[EMAIL PROTECTED]
 wrote:
>
>
>
> > I'd agree with mr deo.
> > Roadrunner interconnects look like a big step backward from other PR-
> > heavy American supercomputers.
>
> http://www.lanl.gov/orgs/hpc/roadrunner/pdfs/Kerbyson%20-%20RR%20Mode...
>
> The predicted worst-case latency is about the same as Blue-Gene.  Red
> Storm routing/switching looks like Blue Gene.  Columbia uses both
> Infiniband and Numalink in a fat tree like Roadrunner.
>

My understanding of p.10 is that 2-way latency between SPEs on two
neighbor triblades is ~8 usec i.e. about the same as node-to-node
latency in the whole 65K-node machine.
I didn't find any estimates for worst-case latency in the 10K-node
configuration. My personal uneducated guess - 10 times worse than BG/L
in the worst case and 5 time worse in average loaded case.