Files
sglang/test/registered/unit
laoyao0822 cd4412a4b8 Reuse IPC descriptors across CP shared-KV layers
CP shared-KV slot remaps already have forward-batch lifetime, but the IPC materialize path rebuilt owner/source/dense descriptor tensors on every layer. Cache prefix/current IPC descriptors on the token and paged slot-remap objects, keyed by layout, spans, device, descriptor kind, and prefix capacity, so all model layers can reuse the same request/batch-plan descriptors.

Constraint: Small-extend cache-hit workloads showed descriptor setup could exceed the all-reduce baseline before any IPC kernel work ran.

Rejected: Global descriptor cache | slot-remap lifetime is safer and avoids stale entries across request/batch-plan changes.

Rejected: Cache without physical page capacity | prefix descriptors encode capacity-invalid pages and must miss when capacity changes.

Confidence: high

Scope-risk: moderate

Directive: Do not reuse descriptors across different slot_logical_pages identity, CP layout, spans, device, or prefix capacity; stale descriptors can alias dense slots across requests.

Tested: Local py_compile; local git diff --check; remote g0034 cjy-glm5-new targeted descriptor tests 2 passed; remote full test_cp_shared_kv_runtime.py 146 passed, 21 warnings, 2 subtests passed.

Not-tested: Full ETE throughput/accuracy after descriptor cache; CUDA service benchmark still needed to quantify speedup.
(cherry picked from commit addd1ca1571e41458315d15304a0e841682fe8fa)
2026-06-13 00:58:47 +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.