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.
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)
• 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)
5. Check resource usage on the machine running locust (not just CPU, but also things like network etc)

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

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