@roberth, here’s an example of building llc from LLVM across a few version bumps (at a derivation-per-sourcefile granularity):
┌───────────────────────────┬────────┬─────────┬─────────────┬────────────────┐
│ Rung │ ninja │ Shinobi │ ninja edges │ Shinobi chunks │
├───────────────────────────┼────────┼─────────┼─────────────┼────────────────┤
│ 21.1.1 cold │ 207.0s │ 229.0s │ 1776 │ 1773 │
├───────────────────────────┼────────┼─────────┼─────────────┼────────────────┤
│ → 21.1.2 (adjacent patch) │ 91.0s │ 88.1s │ 558 │ 537 │
├───────────────────────────┼────────┼─────────┼─────────────┼────────────────┤
│ → 21.1.8 (6 patches) │ 84.5s │ 89.7s │ 567 │ 549 │
├───────────────────────────┼────────┼─────────┼─────────────┼────────────────┤
│ → 21.1.8 (from 21.1.7) │ 9.8s │ 15.0s │ 102 │ 93 │
├───────────────────────────┼────────┼─────────┼─────────────┼────────────────┤
│ → 22.1.1 (major) │ 200.4s │ 211.0s │ 1809 │ 1807 │
└───────────────────────────┴────────┴─────────┴─────────────┴────────────────┘
You’re right that on a major bump it didn’t really help, but it was like 2.5x faster on the two patch bumps and one was 15x faster (apparently it didn’t touch any headers, so cut-off was quick. Now, there is still some overhead I have not pinnned down or that got lost in the forest of envvar variations, but if it can make a package bump evaluate ~2x faster on average, I think it would be a big to resource utilisation efficiency in Hydra?
Maybe you were also misled by:
because that was supposed to be 5:00 PM, actually. I assumed this one was correct and " CET (Central European Time): 7:00 PM Thursdays" was an hour off (we’re +2 right now). Timezones are hard xD