Has anyone faced in-consistency with respect to the performance of GitHub Runners?

I’m using Mac VMs to run my workflows and I’m seeing inconsistency wrt sequential builds.

Env : Mac OS - latest, Xcode - 11.5

The same workflow which finished in ~20 mins, when triggered again with same parameters is taking ~35-40 mins with no change to the codebase.

Any Idea why this performance Inconsistency

Probably because the VMs are provisioned on different hardware and because the hardware is shared between multiple VMs. Occasional “noisy neighbors” could explain the inconsistency.

Agree but this add upto my bill :slight_smile:

I’ve seen that too for macOS builds – with build times up to 150%
I was also suspecting either different host hardware (e.g. CPU generation) or (slight) over-provisioning, which could cause this (with full CPU load on all threads).

Sorry for the experience!

Github generates images for workflow using the https://github.com/actions/virtual-environments repository. It’s recommended to raise an issue ticket there with detail workflows and info. Dev team will help to check and fix.


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