If your test-suite pass rate is significantly greater than 70% (and statistically independent), you can gain throughput by grouping PRs into batches. For examp

If your test-suite pass rate is significantly greater than 70% (and statistically independent), you can gain throughput by grouping PRs into batches. For example, if the pass rate is 80%, then by batching 3 PRs together there's a 51.2% chance to pass with all three, which would save 2 test runs. and a 48.8% to fail, which would cost 1 extra run. That's a pretty substantial increase in throughput.