Repeated GSM8K/cache-hit traffic can drain a CP owner lane while exact allocation still succeeds. This changes L1/L2 free-room logic so the trigger accounts for the pending allocation, then evicts a minimum target chunk or the exact shortage, whichever is larger. CP load-back also performs best-effort owner-lane free-room eviction before admitting tiny cache hits that would otherwise skew one lane. The commit also adds gated bs>1 prefill timing markers around recv/bootstrap/batch/inflight polling so future hangs expose the scheduler boundary instead of only surfacing as a watchdog shutdown. The post-fix repeat GSM8K failure is recorded as an active regression to continue investigating, not as old-process noise. Constraint: Free-room policy must reduce repeated eviction and owner-lane starvation without reserving required+target pages after every allocation Rejected: Evict to required+target availability | wastes L1/L2 residency under many short cache hits Rejected: Treat free-room misses as fatal on load-back | exact capacity should remain the strict admission condition Confidence: medium Scope-risk: moderate Directive: Do not remove the gated bs>1 timing markers until repeat-GSM8K hangs have a direct failing boundary Tested: git diff --check Tested: python -m py_compile for touched Python files Tested: remote earlier test_cp_shared_kv_layout.py and test_cp_hicache_metadata.py passed 157 tests after this free-room formula Not-tested: Two full repeat GSM8K runs after this commit; latest repeat still killed prefill and requires follow-up root-cause work
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.