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When KPD rebases all pending PR branches after an upstream commit lands
(on bpf-next/master, bpf/master) or after a vmtest CI update, hundreds
of workflow runs get triggered within seconds, which may cause various
glitched due to increased stress on the runners.
Add a stagger script that runs as the first step of the set-matrix job
and detects the "storm" condition by checking:
- This is a PR synchronize event (force-push rebase, not a new PR)
- The base branch was updated within the last 30 minutes (KPD just
mirrored upstream)
- Active workflow runs (queued + in-progress) are at least half the
number of open PRs, indicating a bulk rebase rather than normal
organic CI activity
When all conditions are met, the script sleeps for random 1-15 minute
intervals in a loop. As runs complete or get cancelled the ratio drops
and waiting runs proceed naturally. A hard cap of 2 hours prevents
indefinite waiting.
Because the workflow already uses cancel-in-progress on a per-branch
concurrency group, a newer force-push will cancel a sleeping set-matrix
job before any expensive build/test work starts.
During normal operation (developer pushes, single PR rebases, new PRs)
the storm condition is never true and the script exits immediately with
zero delay.
Assisted-by: Claude:claude-opus-4-6
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
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When KPD rebases all pending PR branches after an upstream commit lands (on bpf-next/master, bpf/master) or after a vmtest CI update, hundreds of workflow runs get triggered within seconds, which may cause various glitched due to increased stress on the runners.
Add a stagger script that runs as the first step of the set-matrix job and detects the "storm" condition by checking:
When all conditions are met, the script sleeps for random 1-15 minute intervals in a loop. As runs complete or get cancelled the ratio drops and waiting runs proceed naturally. A hard cap of 2 hours prevents indefinite waiting.
Because the workflow already uses cancel-in-progress on a per-branch concurrency group, a newer force-push will cancel a sleeping set-matrix job before any expensive build/test work starts.
During normal operation (developer pushes, single PR rebases, new PRs) the storm condition is never true and the script exits immediately with zero delay.
Assisted-by: Claude:claude-opus-4-6