Two latent CP shared-KV L2 correctness fixes, landed BEFORE L3 (not in an L3 commit). Surfaced by a per-CP8-instance (CP8DP2EP16) scoping review. PREREQ-1 (CP-group scoping). The B1 commit/evict consensus collectives (writing_check ReduceOp.MIN, placement_digest MIN/MAX + its tp_world_size<=1 entry guard, drain_storage_control_queues, the evict/prefetch MINs, the flush barrier) AND cache_controller.prefetch_tp_group all derive from self.tp_group/self.tp_world_size, which was params.tp_cache_group. tp_cache_group equals the CP group ONLY at dp_size=1 (enable_dp_attention False -> tp_cpu_group, and attn_cp_size==tp_size -> _ATTN_CP==_TP) -- the sole reason B1 works today. Under CP8DP2 (DP attention, attn_tp_size=1) tp_cache_group is the size-1 attn-TP group, so every `tp_world_size>1` collective silently no-ops per rank and the placement assert self-disables -> divergent placement -> shared-slab corruption. Fix: for CP hicache (cp_size>1) scope self.tp_group to the CP cpu group (get_attention_cp_group().cpu_group -- already used for the slab-handle broadcast) + self.tp_world_size to its size. A no-op handle change at dp_size=1 (same group object); the intended fix at CP8DP2. The single init-point change propagates to every consensus collective + un-gates prefetch_tp_group + re-enables the placement assert. PREREQ-2 (flush reset). HiRadixCache.reset() cleared the radix tree + host pool but never reset CpSharedL2PageAllocator -> stale free list/ranges/committed after flush_cache (leak; the shared pool was never reclaimed). Added CpSharedL2PageAllocator.reset() (rebuild the per-slab free list all-free, drop ranges + committed, restore the freshly-built placement_digest) called from cache_controller.reset() after the ack queues are cleared. Safe: flush_cache is idle-gated (no in-flight backup/reserve). This is also L3's clear hookpoint. Validation: new test_reset_restores_freshly_constructed_all_free_state + 89/89 pool suite (torch-2.11 container) + import smoke. PREREQ-1 is a no-op at dp_size=1 (live no-regression confirmed on the next prefill restart); CP8DP2 correctness is by construction (CP-group membership verified) pending a 2-machine run. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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.