[Wrf-users] Recent smpar-only benchmarks?
Andrew Robbie (Gmail)
andrew.robbie at gmail.com
Tue Mar 8 15:16:22 MST 2011
On 09/03/2011, at 5:17 AM, Bart Brashers wrote:
> Has anyone done some recent smpar-only WRF benchmarking of these two
> Intel Xeon X5660 (6 core, 2.8 GHz)
> AMD Opteron 6174 (12 core, 2.2. GHz)
> You can get twice as many cores from the AMD system compared to the
> Intel system, for about the same amount of money.
I'd like to see some numbers on this too. It actually quite possible
to get a quad-socket
board populated with AMD 8 core (eg 6134) for less than a dual socket
So 32 AMD opteron cores for the same price as 12 nehalem ones, because
CPU has no price penalty for running quad socket.
However I think the more relevant limitation is the memory bandwidth
available. Each AMD
socket addresses one four-way interleave RAM bank, and each Intel has
interleave bank. However, especially in the case of the AMD 12 core,
that bandwidth is being
split among many cores. The AMD chip also has an unusual cache design
pair of cores has shared access to a pair of FPUs -- hard to guess how
this effects real
> Note I'm not interested in dmpar scaling, so only up to 24 (Intel)
> or 48
> (AMD) cores per run. I typically have many 5-day chunks to run, so I
> use smpar only.
I think dmpar benchmarks might also be greatly influenced by other
tunables to do with MPI.
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