chore(ci): use a 600s system-tests scheduling budget

[cgcote]

What does this PR do?

Raises the Ruby system-tests scheduling target from 300 to 600 seconds.

Pins system-tests to 52cecf6f2c74f3d41e57e4352cf41daf0f7a51b5, which refreshes the Ruby p75 timing estimates used to balance end-to-end shards.

Motivation:

The 300-second target is shorter than several Ruby weblog build estimates and leaves too little execution budget for their scenarios.

The refreshed estimates and 600-second target reduce the workflow's long tail:

Metric	Previous run	Updated run	Change
Total workflow duration	22m33s	15m41s	30.5% faster
End-to-end shards	249	256	+7
p75 shard duration	6m35s	5m52s	10.9% faster
p90 shard duration	8m13s	6m30s	20.9% faster
Slowest shard	15m54s	10m35s	33.4% faster
Shards over 600 seconds	16	12	25% fewer

The remaining shards over the target finished within 35 seconds of it, indicating substantially better scheduling balance.

Change log entry

None. This is an internal CI scheduling change.

Additional Notes:

The pinned system-tests commit is merged into DataDog/system-tests's main branch, as confirmed by the workflow guard.

How to test the change?

• Baseline System Tests run
• Updated System Tests run
• Confirm the updated run succeeds with unchanged scenario coverage.
• Compare the end-to-end shard distribution and total workflow duration with the baseline.

The updated run completed successfully.

[datadog-prod-us1-4]

✅ All CI checks and tests passed.

🎉 All green!

🧪 All tests passed
❄️ No new flaky tests detected

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 90.65% (-0.01%)

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: c9d842b | Docs | View more details | Give us feedback!}

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-09T09:50:28.040563Z	c9d842b	Draft marked ready
🔒 Security Review	✅ Completed 2026-10-09T09:52:29.007544Z	c9d842b	Draft marked ready

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review" or "@codex security review".

Codex reacts with 👀 while any review is running, comments if it has suggestions, and reacts with 👍 once all reviews finish with no findings.

[datadog-prod-us1-4]

More details

The 600-second scheduling target preserves the expected numeric input, and the reusable workflow and checkout pins match. Independent verification of the linked CI runs was blocked by GitHub HTTP 403.

Was this helpful? React 👍 or 👎

_{Open Bits AI session}

_{🤖 Bits Code Review · Commit c9d842b · @DataDog review to ask questions}

[eregon]

Nice!