Files
sglang/test/registered/unit
laoyao0822 96bf7a2594 Reduce CP shared-KV prepare overhead without diagnostic log noise
The CP shared-KV path now has a gated tai-kernel replacement for NSA index
K/scale plus MQA range preparation, and Phase8 prefetch can skip tiny prefixes
that do not cover all CP lanes. The Phase9 plan documents the next scheduler
work for overlapping CP communication with peer-request attention windows.

Temporary diagnostic logs added while validating prefetch ownership and fused
index prepare routing were removed before committing so the runtime path does
not add log-only synchronization, log counters, or shape-reporting overhead.

Constraint: Production profiling showed small per-request CPU/GPU overhead from diagnostic logging and sync-prone debug counters.
Rejected: Keep fused-index prepare fallback/used logs behind a new env var | it leaves another runtime branch and logging surface for a path that should be benchmarked with profiler evidence instead.
Rejected: Keep owned page-count prefetch logs | they require sync-prone tensor reductions and were only useful for one-off diagnosis.
Confidence: medium
Scope-risk: moderate
Directive: Reintroduce CP shared-KV diagnostics only behind explicit debug paths, and avoid .item()/shape-heavy logging in hot prefill paths.
Tested: git diff --check for staged sglang-dev changes.
Tested: AST parse for environ.py, cp_shared_kv_prefetch.py, cp_shared_kv_runtime.py, nsa_indexer.py, and test_cp_shared_kv_runtime.py.
Not-tested: Full unit test suite.
Not-tested: Multi-node GLM5 prefill/decode/router runtime after this exact commit.
2026-05-12 20:19:11 +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.