ASGI Server Performance

Comparing the performance of various ASGI servers.

Setup

Install the requirements:

pip install -r requirements.txt

Start one of the ASGI servers, using the named shell script. For example:

# Increase the max number of files which can be open:
ulimit -Sn 10000

# Start the server:
./daphne.sh

Start Locust, and three workers, each in a separate terminal tab.

# tab 1
locust --master

# tab 2
locust --worker

# tab 3
locust --worker

# tab 4
locust --worker

Open http://0.0.0.0:8089/ in a browser to see the Locust GUI. Start a new test.

Number of Locust workers

The test was run using a 2.7 GHz Core i7 (9th Gen) processor with 6 cores, and 16 GB RAM. Your mileage may vary - make sure there are enough workers that none of them hit 100% CPU usage, as it will give misleading results.

You can see the CPU usage of each worker in the workers tab of the Locust GUI.

Server configuration

To get fair results, logging was disabled for each server.

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Results

Uvicorn has the largest throughtput, and Hypercorn and Daphne were basically equal.

Uvicorn

Hypercorn

Daphne

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Conclusions

If performance is your main aim, then Uvicorn is a good starting point. However, all of the servers performed well, so all are good choices.