Why does my build get slower every Friday

questionsystems · 13 points · 4 comments

Same repo, same machine, same command. Monday it is 40 seconds and Friday it is four minutes.

I have ruled out the obvious: no new dependencies landed, the lockfile is untouched, and the machine is not thermally throttled (I watched it).

The only thing that changes across the week is the number of branches I have checked out. Does anyone know a mechanism by which that would matter?

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4 comments

2026-10-14
This is the one I was looking for last week. Thank you.
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2026-10-14
Worth adding that this only holds if the clock is monotonic. Ours was not, and the failure looked exactly like a slow disk.
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2026-10-14
I have hit this and solved it the other way, and I now think your way is better.
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2026-10-14
Do you have a link for the second claim? I want to read the original.
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