2.16.2.3. Yardstick Test Case Description TC004

Cache Utilization

test case id

OPNFV_YARDSTICK_TC004_CACHE Utilization

metric

cache hit, cache miss, hit/miss ratio, buffer size and page cache size

test purpose

The purpose of TC004 is to evaluate the IaaS compute capability with regards to cache utilization.This test case should be run in parallel with other Yardstick test cases and not run as a stand-alone test case.

This test case measures cache usage statistics, including cache hit, cache miss, hit ratio, buffer cache size and page cache size, with some wokloads runing on the infrastructure. Both average and maximun values are collected.

The purpose is also to be able to spot the trends. Test results, graphs and similar shall be stored for comparison reasons and product evolution understanding between different OPNFV versions and/or configurations.

test tool

cachestat

cachestat is a tool using Linux ftrace capabilities for showing Linux page cache hit/miss statistics.

(cachestat is not always part of a Linux distribution, hence it needs to be installed. As an example see the /yardstick/tools/ directory for how to generate a Linux image with cachestat included.)

test description

cachestat test is invoked in a host VM on a compute blade, cachestat test requires some other test cases running in the host to stimulate workload.

configuration

File: cachestat.yaml (in the ‘samples’ directory)

Interval is set 1. Test repeat, pausing every 1 seconds in-between. Test durarion is set to 60 seconds.

SLA is not available in this test case.

applicability

Test can be configured with different:

  • interval;

  • runner Duration.

Default values exist.

usability

This test case is one of Yardstick’s generic test. Thus it is runnable on most of the scenarios.

references

cachestat

ETSI-NFV-TST001

pre-test conditions

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

No POD specific requirements have been identified.

test sequence

description and expected result

step 1

A host VM with cachestat installed is booted.

step 2

Yardstick is connected with the host VM by using ssh. ‘cache_stat’ bash script is copyied from Jump Host to the server VM via the ssh tunnel.

step 3

‘cache_stat’ script is invoked. Raw cache usage statistics are collected and filtrated. Average and maximum values are calculated and recorded. Logs are produced and stored.

Result: Logs are stored.

step 4

The host VM is deleted.

test verdict

None. Cache utilization results are collected and stored.