CP shared-KV bs>1 exposed two separate overhead sources: HiCache load-back could thrash near capacity, and partial-current sync compose could all-reduce row-major page-table gaps between request prefixes. Keep the intended batch-plan path for bs=1, but make host/L1 free-room handling less reactive and teach the MLA/index sync compose path to use exact per-request prefix slot spans instead of one bounding span.\n\nThe exact-span path preserves the single-span IPC fast path for bs=1/single-span cases, while avoiding over-communication for heterogeneous cache-hit batches. The HiCache metadata tests cover host/L1 free-room propagation and load-back batching behavior.\n\nConstraint: bs=1 using CPSharedKVBatchPlan is the expected steady-state path and must not be treated as a regression.\nConstraint: Remote production-like validation runs inside g0034 container /sgl-workspace/sglang-tai.\nRejected: Disable batch-plan for bs=1 | user confirmed this is intended behavior and it would hide the actual bs>1 overhead.\nRejected: Keep one bounding prefix span for bs>1 | row-major page tables can include current/gap slots and inflate per-layer all-reduce work.\nConfidence: medium\nScope-risk: moderate\nDirective: Do not replace exact prefix spans with a single row-major bounding span unless ETE data proves collective launch count dominates gap over-communication.\nTested: g0034 docker py_compile for changed Python/test files.\nTested: g0034 docker PYTHONPATH=python python -m pytest -q test/registered/unit/mem_cache/test_cp_shared_kv_runtime.py test/registered/unit/mem_cache/test_cp_hicache_load_back_owner_lanes.py test/registered/unit/mem_cache/test_cp_hicache_metadata.py — 241 passed, 5 warnings, 2 subtests passed.\nNot-tested: Full ETE bs>1 throughput after the exact-prefix-span change.\nNot-tested: CUDA kernel benchmark and live traffic replay.
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
- Find the source file under
python/sglang/srt/. - 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 - 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") - Run locally:
pytest test/registered/unit/ -v # all unit tests pytest test/registered/unit/mem_cache/ -v # one module - 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()orEngine(...). - No model weight loading.
- Use
CustomTestCase(fromsglang.test.test_utils, adds CI retry). - Use
unittest.mockfor dependencies that are expensive to construct.