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 IX\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 IX\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 PCI Express links.
          #  Size   Total time (usec)    RTT (usec)    Latency (usec)
                1                2487          2.49              1.24	
                2                2456          2.46              1.23	
                3                2475          2.48              1.24	
                4                2472          2.47              1.24	
                5                2537          2.54              1.27	
                6                2563          2.56              1.28	
                7                2560          2.56              1.28	
                8                2520          2.52              1.26	
                9                2529          2.53              1.26	
               10                2534          2.53              1.27	
               11                2543          2.54              1.27	
               12                2576          2.58              1.29	
               13                2502          2.50              1.25	
               14                2512          2.51              1.26	
               15                2596          2.60              1.30	
               16                2481          2.48              1.24	
               24                2493          2.49              1.25	
               32                2528          2.53              1.26	
               48                2562          2.56              1.28	
               64                2741          2.74              1.37	
               96                2871          2.87              1.44	
              128                2906          2.91              1.45	
              256                3476          3.48              1.74	
              512                4261          4.26              2.13	
             1024                5740          5.74              2.87	
             2048                8654          8.65              4.33	
             4096               11610         11.61              5.80	
             8192               14707         14.71              7.35	
            16384               21573         21.57             10.79	
            32768               35151         35.15             17.58	
            65536               62399         62.40             31.20

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.