FAQ

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How do I...

Sort out installation issues

See Installation

Increase my request rate/RPS

1. Increase the number of users. In order to fully utilize your target system you may need a lot of simultaneous users. Locust makes at least one DNS Request per User, so ensure that you're not running into DNS Performance problems / the Flood Protection of your Provider.
2. If response times are unexpectedly high and/or increasing as the number of users go up, then you have probably saturated the system you are testing and need to dig into why. This is not really a Locust problem, but here are some things you may want to check:

• resource utilization (e.g. CPU, memory & network. Check these metrics on the locust side as well)
• configuration (e.g. max threads for your web server)
• back end response times (e.g. DB)

3. If Locust is complaining about high CPU usage on its side

• Run Locust distributed to utilize multiple cores & multiple machines
• Try switching to FastHttpUser to reduce CPU usage

4. If you are using a custom client (not HttpUser or FastHttpUser), make sure any client library you are using is gevent-friendly, otherwise it will block the entire Python process (essentially limiting you to one user per worker)

Clear cookies, to make the next task iteration seem like a new user to my system under test

Call self.client.cookies.clear() at the end of your task.

Create a Locust file based on a recorded browser session

Try using Transformer

How to run a Docker container of Locust in Windows Subsystem for Linux (Windows 10 users)?

If you use WSL on a Windows computer, then you need one extra step than the "docker run ..." command: copy your locusttest1.py to a folder in a Windows path on your WSL and mount that folder instead of your normal WSL folder:

$ mkdir /c/Users/[YOUR_Windows_USER]/Documents/Locust/
$ cp ~/path/to/locusttest1.py /c/Users/[YOUR_Windows_USER]/Documents/Locust/
$ docker run -p 8089:8089 -v /c/Users/[YOUR_Windows_USER]/Documents/Locust/:/mnt/locust locustio/locust:1.3.1 -f /mnt/locust/locusttest1.py

Check the list of issues (a lot of questions/misunderstandings are filed as issues)