Difference between revisions of "UM version4.5 benchmarks"

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* If the model is not filesystem-bound, it is often (MPI massage) latency-bound.
 
* If the model is not filesystem-bound, it is often (MPI massage) latency-bound.
 
* Only the master process writes output, this can lead to load-balance issues, which hinder scaling.
 
* Only the master process writes output, this can lead to load-balance issues, which hinder scaling.
* Worst case message latencies for a cohort of processors are what matter for scaling.
+
* Worst case message latencies for a cohort of processors are what matter for scaling.  The vast majority of messages are either ~100 bytes or ~1KB in size.  Latencies are reported for these key message sizes.
  
 
=Intel Westmere=
 
=Intel Westmere=

Revision as of 15:45, 17 December 2012

Benchmarking UM Version4.5 on different Architectures

Preamble

  • Cluster/Parallel file systems are often a bottleneck. Timings are for writing to local disk, unless specified otherwise.
  • If the model is not filesystem-bound, it is often (MPI massage) latency-bound.
  • Only the master process writes output, this can lead to load-balance issues, which hinder scaling.
  • Worst case message latencies for a cohort of processors are what matter for scaling. The vast majority of messages are either ~100 bytes or ~1KB in size. Latencies are reported for these key message sizes.

Intel Westmere

  • Emerald. Intel E5649 (2.53GHz)
  • QDR Infiniband (non-RoCE)
  • GCOMv3.1


IMB ping-pong message latency
0 bytes 128 bytes 1024 bytes
between nodes ~2.0us ~2.4us ~4.7us

FAMOUS

Domain Decomposition Number of Cores Model-years/day
4x3 12 ~313
6x4 24 ~360
12x3 36 ~424

HadCM3

Domain Decomposition Number of Cores Model-years/day
4x3 12 ~24
6x4 24 ~40
12x3 36 ~60

Intel SandyBridge

  • Test system: Quad socket, 8-core E-4650L (2.60GHz) (L for Low power)
  • 20MB L3 cache
  • GCOMv3.1


IMB ping-pong message latency
0 bytes 128 bytes 1024 bytes
between sockets ~0.70us ~1.15us ~2.0us

FAMOUS

Domain Decomposition Number of Cores Model-years/day
4x2 8 ~327
8x2 16 ~450
8x4 32 ~480
  • The last line of this table shows a real problem scaling beyond 16 cores. Load balance? (Latencies are much better than QDR IB.)
  • Would like to try to improve file writing performance and re-run.

HadCM3

Domain Decomposition Number of Cores Model-years/day
8x2 16 ~48
8x4 32 ~65