benchmark bot: Found no runs to compare against.

Stream: lean4

[Scott Morrison]

I am frequently finding that !bench reports: Found no runs to compare against.. e.g. see #6298. Does anyone have advice on what to do?

[Sebastian Ullrich]

Previous discussion: https://leanprover.zulipchat.com/#narrow/stream/270676-lean4/topic/speedcenter.20runs.20on.20master/near/379110179

[Eric Wieser]

One easy way to avoid this is to always start your branches from a master commit that has been benchmarked, rather than from HEAD

[Kevin Buzzard]

I was bumping branches to a recent master commit which has been benchmarked (e.g. by searching for mathlib in the speedcenter and then choosing the most recent commit to master which had been benchmarked) and then bumping my branch to that commit; this also seemed to work (although it might all depend on your merge algorithm...)