Yardstick Test Case Description TC010ΒΆ

Memory Latency
test case id OPNFV_YARDSTICK_TC010_Memory Latency
metric Latency in nanoseconds
test purpose Measure the memory read latency for varying memory sizes and strides. Whole memory hierarchy is measured including all levels of cache.
configuration

File: opnfv_yardstick_tc010.yaml

  • SLA (max_latency): 30 nanoseconds
  • Stride - 128 bytes
  • Stop size - 64 megabytes
  • Iterations: 10 - test is run 10 times iteratively.
  • Interval: 1 - there is 1 second delay between each iteration.
test tool

Lmbench

Lmbench is a suite of operating system microbenchmarks. This test uses lat_mem_rd tool from that suite. Lmbench is not always part of a Linux distribution, hence it needs to be installed in the test image
references

man-pages

McVoy, Larry W.,and Carl Staelin. “lmbench: Portable Tools for Performance Analysis.” USENIX annual technical conference 1996.
applicability

Test can be configured with different:

  • strides;
  • stop_size;
  • iterations and intervals.

There are default values for each above-mentioned option.

SLA (optional) : max_latency: The maximum memory latency that is accepted.
pre-test conditions

The test case image needs to be installed into Glance with Lmbench included in the image.

No POD specific requirements have been identified.
test sequence description and expected result
step 1

The host is installed as client. Lmbench’s lat_mem_rd tool is invoked and logs are produced and stored.

Result: logs are stored.
test verdict Test fails if the measured memory latency is above the SLA value or if there is a test case execution problem.