[Rockdu]

Summary

The sglang-miles port of #44603 (the same 15 commits) on the sglang-miles bump to sglang v0.5.22; it supersedes #44239. The one difference from #44603: sglang-miles keeps its trajectory semantics from #40786 (timesteps cover every step, latents follow rollout_return_step_indices, latent_step_indices is recorded), which miles-diffusion depends on.

Rollout stops being a scheduler / denoising-stage mixin: each latent stream of a rollout request gets a FlowRolloutController whose transition the loop passes into scheduler.step. Serving is untouched; rollout numerics do not change.

It supersedes the design in #37940; @niehen6174 is co-author on the derived commits. @JingwenGu0829 found the issues fixed in commits 13 and 14 (Rockdu#4) and is co-author on commits 13 to 15.

How it works

• FlowMatchEulerDiscreteScheduler.step(..., transition=None) runs transition or self._transition. Loops pass **rollout_step_kwargs(batch), which is empty for serving requests, so every scheduler keeps its serving call.
• Hooks in rollout_hooks.py: prepare_rollout_if_enabled (before the SP shard), init_rollout_env_if_enabled, rollout_step_kwargs, finalize_rollout_if_enabled; all no-ops for serving.
• Wired into generic DenoisingStage, Cosmos3 and LTX-2. A loop without a scheduler (MiniMax H3, next PR) passes its own build_controller and ode_transition.

Review guide

Commits 2, 3, 4 and 6 are mechanical moves verified by the chain verifier (4/4 proofs) and commit 1 is a pure rename; skim them. Review commits 5, 7 to 11 and 13 to 15.

Tests

• GPU A/B against [Refactor] diffusion: Rollout controller as a scheduler-step plugin instead of mixins #44603 and against the previous sglang-miles ([Diffusion][sglang-miles] refactor: rollout controller as a scheduler-step plugin instead of mixins #44239): bitwise identical for Qwen-Image, Cosmos3 and LTX-2.3 at SP 1 and 2.
• miles-diffusion full e2e on this tree (fix: adapt to sglang-miles on sglang v0.5.22 and the rollout-controller refactor radixark/miles_diffusion#315): every suite passes, bitwise equal to its standard. MiniMax H3 GRPO and Qwen-Image GRPO were re-recorded for changes that came with the bump ([Fix] MiniMax H3: honor requested inference step count #38671 + [Diffusion] MiniMax-H3 fuse the video VAE decoder's RMSNorm and QK RoPE #41906 for H3, [diffusion] fix: shard Qwen-Image adaLN modulation and text FFN under TP #43691 for Qwen-Image), attributed in fix: adapt to sglang-miles on sglang v0.5.22 and the rollout-controller refactor radixark/miles_diffusion#315.
• Rollout unit tests: 74 passed.

Checklist

• Format your code according to the Format code with pre-commit.
• Add unit tests according to the Run and add unit tests.
• Update documentation according to Write documentations. Not needed: no user-facing change.
• Provide accuracy and speed benchmark results according to Test the accuracy and Benchmark the speed. Accuracy is covered above; no speed impact expected.
• Follow the SGLang code style guidance.

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CI States

Latest PR Test (Base): ❌ Run #39022334419
Latest PR Test (Extra): ❌ Run #39022334380
Latest PR Test (AMD ROCm 10): ❌ Run #39022334446