Thursday, January 17, 2013

OFED Performance Micro-Benchmark Latency Test

Open Fabrics Enterprise Distribution (OFED) has provided simple performance micro-benchmark has provided a collection of tests written over uverbs. The notes taken from OFED Performance Tests README
  1. The benchmark uses the CPU cycle counter to get time stamps without a context switch.
  2. The benchmark measures round-trip time but reports half of that as one-way latency. This means that it may not be sufficiently accurate for asymmetrical configurations.
  3. Min/Median/Max results are reported.
    The Median (vs average) is less sensitive to extreme scores.
    Typically, the Max value is the first value measured Some CPU architectures
  4. Larger samples only help marginally. The default (1000) is very satisfactory.   Note that an array of cycles_t (typically an unsigned long) is allocated once to collect samples and again to store the difference between them.   Really big sample sizes (e.g., 1 million) might expose other problems with the program.
On the Server Side
# ib_write_lat -a

On the Client Side
# ib_write_lat -a Server_IP_address

For more information, do take a look at OFED Performance Micro-Benchmark Latency Test

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