3. SuperSockets Functionality and Performance

This section describes how to verify that SuperSockets are working correctly on a cluster.

3.1. SuperSockets Benchmarks

3.1.1. latency_bench

Latency_bench is a benchmark in the Dolphin software distribution that can be used to validate the functionality and performance of any Ethernet compliant network. The basic usage requires two machines (n1 and n2). Start the server process on Cluster Node n1 as server:

C:\Program Files\Dolphin Express PX\SuperSockets\>"Bin\dis_ssocks_run.exe"
Demo\latency_bench.exe -server

On Cluster Node n2, run the client side of the benchmark like:

C:\Program Files\Dolphin Express PX\SuperSockets\>"Bin\dis_ssocks_run.exe"
Demo\latency_bench.exe -client n1

The output for a working setup should look like this:

Testing PINGPONG transfers (back-and-forth)
Socket transfers are made over Dolphin PCI Express links.
#  Size   Total time (usec)    RTT (usec)    Latency (usec)
      1                2036          2.04              1.02	
      2                2029          2.03              1.01	
      3                2038          2.04              1.02	
      4                2025          2.02              1.01	
      5                2087          2.09              1.04	
      6                2096          2.10              1.05	
      7                2105          2.11              1.05	
      8                2083          2.08              1.04	
      9                2084          2.08              1.04	
     10                2097          2.10              1.05	
     11                2098          2.10              1.05	
     12                2098          2.10              1.05	
     13                2094          2.09              1.05	
     14                2097          2.10              1.05	
     15                2103          2.10              1.05	
     16                2085          2.09              1.04	
     24                2094          2.09              1.05	
     32                2115          2.12              1.06	
     48                2148          2.15              1.07	
     64                2219          2.22              1.11	
     96                2306          2.31              1.15	
    128                2447          2.45              1.22	
    256                2876          2.88              1.44	
    512                3606          3.61              1.80	
   1024                4974          4.97              2.49	
   2048                7429          7.43              3.71	
   4096                6972          6.97              3.49	
   8192                8688          8.69              4.34	
  16384               12834         12.83              6.42	
  32768               20954         20.95             10.48	
  65536               37996         38.00             19.00	

The latency running over SuperSockets should normally start around 1-1.5µs. Recent machines with Dolphin PCI Express IX and PX deliver latencies at 1-1.1µs; on older machines, the latency may be higher. Latencies above 5µs indicate a problem; typical Ethernet latencies start at 20-75µs and more depending on your system.