Currently we are at ~ 9 minutes to run the test_on_push workflow. I think we should keep this around 5-10 minutes, so this should probably be reduced unless others have different thoughts @martinjrobins @NicolaCourtier?

A few thoughts on this:

• Reduce the number of optimisers that are performance tested (i.e. asserted on the identified parameter)
• Reduce the maximum number of iterations for each optimiser during performance testing (this may result in more failures)
• Split the test_on_push workflow so that performance tests are only run for a PR.