Files
sglang/test/registered/unit
laoyao0822 ceb5345410 Account decode handoff queues in DP load snapshots
Decode DP dispatch was collapsing onto a few ranks because the controller only randomizes among exact minimum load pairs. The load snapshot undercounted decode handoff work: pending prefill-info requests were absent, and DecodeRequest wrappers in prealloc/transfer queues were skipped because their rid lives on .req.

This makes scheduler load accounting unwrap DecodeRequest items and include pending decode requests, so TOTAL_TOKENS sees queued handoff backlog instead of repeatedly treating busy ranks as empty.

Constraint: Do not mask imbalance with synthetic per-request token penalties; dispatch should be driven by accurate observed load.

Rejected: Add req*4000 or other queue penalties | heuristic, workload-dependent, and hides the accounting bug.

Confidence: medium

Scope-risk: moderate

Directive: Any new decode handoff queue must be included in get_load() or DP routing can regress to stale/min-load collapse.

Tested: Remote cjy-glm5-new: PYTHONPATH=python python -m pytest -q test/registered/unit/observability/test_scheduler_metrics_load.py test/registered/unit/managers/test_prefill_adder.py -> 27 passed.

Not-tested: Fresh decode ETE distribution after service restart.
2026-06-13 02:35:10 +08:00
..

Unit Tests

Component-level tests that do not launch a server or load model weights. Tests can use CPU or GPU — the key criterion is no server process.

Quick Start

  1. Find the source file under python/sglang/srt/.
  2. Create the corresponding test here, mirroring the source tree:
    srt/mem_cache/radix_cache.py       →  unit/mem_cache/test_radix_cache.py
    srt/sampling/sampling_params.py    →  unit/sampling/test_sampling_params.py
    
  3. Register for CI at the top of the file (after imports, before test classes):
    from sglang.test.ci.ci_register import register_cpu_ci
    register_cpu_ci(est_time=5, suite="stage-a-test-cpu")
    # or: register_cuda_ci(est_time=10, suite="stage-b-test-1-gpu-small")
    
  4. Run locally:
    pytest test/registered/unit/ -v            # all unit tests
    pytest test/registered/unit/mem_cache/ -v  # one module
    
  5. Run with coverage:
    # summary
    pytest test/registered/unit/ --cov --cov-config=.coveragerc -v
    
    # PR incremental check (require ≥60% on changed lines)
    pytest test/registered/unit/ --cov --cov-config=.coveragerc --cov-report=xml
    diff-cover coverage.xml --compare-branch=origin/main --fail-under=60
    

Example

"""Unit tests for <module> — no server, no model loading."""

from sglang.test.ci.ci_register import register_cpu_ci

register_cpu_ci(est_time=5, suite="stage-a-test-cpu")

import unittest

from sglang.srt.<module> import TargetClass
from sglang.test.test_utils import CustomTestCase


class TestTargetClass(CustomTestCase):
    def test_basic_behavior(self):
        obj = TargetClass(...)
        self.assertEqual(obj.method(), expected)


if __name__ == "__main__":
    unittest.main()

Rules

  • No popen_launch_server() or Engine(...).
  • No model weight loading.
  • Use CustomTestCase (from sglang.test.test_utils, adds CI retry).
  • Use unittest.mock for dependencies that are expensive to construct.