CODEWITHSUNDEEP
c#azurescalabilityazure-functions
Dmitry Andrievsky
Dmitry Andrievsky

Reputation: 1873

Performance of Consumption-hosted Functions on Azure free subscriptions

I am evaluating Azure Functions using Azure Free Trial Subscription. Everything is OK except for performance/scalability.

I developed trivial http-triggered function (C# Class library), that does nothing but sleeps 5 seconds. When executed once, directly, it works like 5s, exactly as expected. But when called 500 times in parallel - execution time grows up to 20-30 seconds.

Function is "hosted" on Consumption plan, so I expected that once required, it is executed on separate VM "automatically". I checked ARR Cookies (that might have stuck my requests to one VM) - no, no cookies at all. Everything looks fine, at least for such simple case (no obvious bottlenecks to check - no DB, no communications, etc.).

So, the question is - is it because of free trial subscription, or I am missing something?

Upvotes: 2

Views: 153

Answers (1)

Chris Anderson
Chris Anderson

Reputation: 8505

There is no difference for Azure Functions on Free Trial Subscriptions. You aren't being slowed down by that.

As @mathewc pointed out, this is due to HTTP scale out having some lag which we're working to improve. You can see some knobs you can control here: https://github.com/Azure/azure-webjobs-sdk-script/wiki/Http-Functions#throttling

If you enable throttling, it will result in 429s, but will help prevent increasing execution times.

Upvotes: 3

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