leaveletandClaude Opus 4.8
512fe92a83
Under overlap scheduling a chunked request's final-chunk write-backup prepare read a stale `is_chunked` (>0): that per-tick counter is decremented in process_batch_result, which the overlap loop runs AFTER the run_batch prepare hook. So prepare floored `backup_end` to a page boundary (the intermediate-chunk rule) and dropped the now-complete final tail page, while the final non-chunked insert builds the radix node at full unaligned length. The exact-equality attach predicate (prepared.logical_len == len(value)) then failed by (num_tokens-1) mod page_size, dropped the per-layer overlap backup, and forced the serial all-layer catch-up (~89% of large chunked requests in prod). Decouple the floor decision from the stale counter: the scheduler marks `req.cp_backup_is_intermediate_chunk = (req is self.chunked_req)` in `_prepare_hicache_write_backups_before_forward` (the live chunked_req identity is the authoritative "will be chunked further" signal, set this tick before run_batch), and the prepare candidate builder floors on that flag instead of `is_chunked`. Intermediate chunks still floor; only the misclassified final chunk now backs up its full tail and attaches the overlap backup. Tests: update the chunked prepare test to the new flag; add a regression test that a final chunk with stale is_chunked reserves the full tail; add an offline repro that drives the real prepare/insert/probe and sweeps unaligned tails. Co-Authored-By: Claude Opus 4.8 <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.