stress-system

A tool to load and stress a multicore architectures using stress-ng.

• Running stress-system
• Options
  • Stressing CPU
  • Stressing other components

Running stress-system

You can run this tool in the following three ways:

• Local
• Using Docker containers
• Using Apptainer containers

Local

To run this tool on your physical machine all you need is to have stress-ng installed. To install stress-ng follow the instructions in its official repository.

Once stress-ng is installed run the tool with:

./run.sh

Using Docker containers

First, you need to build the docker image:

docker build -t stress-system -f container/Dockerfile .

Then you can run the tool:

docker run -ti [-v <host-dir>:<container-dir>] stress-system [-o <container-dir> <other-options>]

To store the logs on your physical machine you have to mount a volume from host to container and specify the container directory as the output parameter of the tool (-o option). Here is an example in which the logs are stored in the /tmp directory of the container, which we can access through the ./out directory from our machine:

docker run -ti -v $(pwd)/out:/tmp stress-system -o /tmp -l 100 -c 0,6,7 

To run the container in background:

docker run -d [-v <host-dir>:<container-dir>] stress-system [-o <container-dir> <other-options>]

Using Apptainer containers

First you need to build Apptainer image (SIF file):

cd container && apptainer build stress.sif stress.def && cd ..

Logs will be written to the /tmp/out/report_$(date '+%d_%m_%Y_%H-%M-%M-%S') directory, as Apptainer shares this directory with the host by default. Therefore, do not modify the tool's output directory. Now run the image in foreground:

apptainer run container/stress.sif [<options-except-output>]

Or in the background:

sudo apptainer instance start container/stress.sif [<options-except-output>]

Options

You can specify the options from the CLI or by modifying the ./experiment/stress-conf.sh configuration file.

# ./run.sh --help
Usage: run.sh [OPTIONS]

Options:
  -i, --iterations <I>    Run tests I times. [Default: 1]
  -b, --time-btw-iters <T>    Wait T seconds between iterations. [Default: 10s]
  -t, --timeout <T>       Stop tests after T seconds. Time units can be specified by using suffixes. [Default: 10s]
  				s = seconds
  				m = minutes
  				h = hours
  				d = days
  				y = years
  -s, --stressors []      Comma-separated list of stressors to run on system. [Default: cpu]
  -l, --cpu-load <P>      Stress CPU with P percent of CPU load. The load will be assigned to cores incrementally. Used together with CPU stressor. [Default: 50%]
                          Example: "run.sh -l 130 -c 3,6" will load core 3 at 100% and core 6 at 30%.
  --cpu-load-types []     Comma-separated list of types of load to stress the CPU. Used together with CPU stressor. [Default: all]
  --other                 Comma-separated list of other stress-ng options specified in key=value format. Example: --other temp-path=<path>
                          Use key=None when stress-ng option doesn't need an input value. WARNING: DON'T USE THIS OPTION 
                          IF YOU DON'T UNDERSTAND IT AT ALL BECAUSE IT COULD RESULT ON UNEXPECTED RESULTS.
  -c, --cores-list []     Comma-separated list of cores on which you want to run the tests [Default: all]
  -o, --output <dir>      Directory to store log files. [Default: ./out]      
  -h, --help              Show this help and exit

Example of use:
  run.sh --timeout 10s --stressors cpu --cpu-load 230 --cpu-load-types double,int64 --cores-list 0,2,4

Stressing CPU

This tool assigns the load incrementally to each core, instead of distributing the load among all available cores. To better understand his behavior see the examples below.

Example 1

run.sh --timeout 10s --stressors cpu --cpu-load 70 --cpu-load-types double --cores-list 0,2,4

Core	Load
0	70%
2	0%
4	0%

It will load core 0 with 70% of load using double tests for 10 seconds. It will ignore cores 2 and 4 as there is not enough load for them.

Example 2

run.sh -i 3 --timeout 1m --stressors cpu --cpu-load 140 --cpu-load-types all --cores-list 0,2,4

Core	Load
0	100%
2	40%
4	0%

It will load core 0 with 100% of load and core 2 with 40% of load using all tests for 1 minute 3 times. It will ignore core 4 as there is not enough load for it.

Example 3

run.sh --timeout 1m --stressors cpu --cpu-load 240 --cpu-load-types all --cores-list 0,2,4

Core	Load
0	100%
2	100%
4	40%

It will load core 0 and 2 with 100% of load and core 4 with 40% of load using all tests for 1 minute.

Example 4

run.sh --timeout 1m --stressors cpu --cpu-load 340 --cpu-load-types all --cores-list 0,2,4

Core	Load
0	100%
2	100%
4	100%

It will load core 0, 2 and 4 with 100% of load using all tests for 1 minute. Although specified load is 340%, the maximum load that can be executed with 3 cores is 300%, so the load value is reassigned to its maximum possible value (300%).

Stressing other components

When using any stressor but cpu it's not possible to specify a particular CPU load. Actually, you can set a CPU load, however, probably the actual load will be diferent from the desired load.

Example

run.sh --timeout 10s --stressors cpu,iomix --cpu-load 150 

Core	Desired Load	Actual Load
0	100%	89%
2	50%	35%
4	0%	0%

While cpu stressor will try to load core 0 with 100% of load and core 1 with 50% of it, iomix stressor will be competing with cpu stressor for the same resources without taking into account any specific load.