LLM inference - completions endpoint

Gatling (Open-Source)
1

Hello,
My task to is test the performance of a LLM. Along with total response time I need the get the time-to-first-token metric. The call is an HTTPS POST, per example ‘https://api.openai.com/v1/chat/completions’ with ‘stream’ option added to the request body ( which serves the response as chat.completion.chunk json pieces for each token back.
Is there any way to achieve this? Thanks.

2

According to the doc, it looks like this would be a SSE.
Then, you can check Gatling’s SSE support.

3

Thanks for the quick response. However, I need to pass a request body and doesn’t look like SseConnectRequestBuilder supports that ( I am at version 3.7)

4

Indeed, I failed to realize that.
Atm Gatling doesn’t support anything but a GET request without a body. The reason is that both the specification and the JavaScript EventSource object only allow this.

Contributions or sponsoring welcome.