[HiCache] Add synchronization for context parallelism (#20460)

Signed-off-by: Vladislav Nosivskoy <vladnosiv@gmail.com>

test/registered/hicache/test_hicache_storage_mooncake_backend.py

@@ -17,6 +17,7 @@ from sglang.test.test_utils import (
     DEFAULT_MLA_MODEL_NAME_FOR_TEST,
     CustomTestCase,
     find_available_port,
+    get_gpu_count,
     is_in_ci,
 )
 
@@ -260,6 +261,39 @@ class TestMooncakeBackendMLAModel(
         return server_args, env_vars
 
 
+@unittest.skipUnless(get_gpu_count() >= 2, "Requires at least 2 CUDA GPUs for TP2+CP2")
+class TestMooncakeBackendQwen330BCP2(
+    HiCacheStorageMooncakeBackendBaseMixin, CustomTestCase
+):
+    """Qwen3-30B with Mooncake HiCache storage, CP2, and TP2."""
+
+    @classmethod
+    def _get_model_name(cls):
+        return "Qwen/Qwen3-30B-A3B-FP8"
+
+    @classmethod
+    def _get_additional_server_args_and_env(cls):
+        server_args, env_vars = super()._get_additional_server_args_and_env()
+        server_args.update(
+            {
+                "--tp-size": 2,
+                "--moe-dp-size": 2,
+                "--attn-cp-size": 2,
+                "--enable-prefill-context-parallel": True,
+                "--trust-remote-code": True,
+                "--cuda-graph-max-bs": 32,
+                "--max-running-requests": 32,
+                "--max-total-tokens": 8192,
+                "--model-loader-extra-config": (
+                    '{"enable_multithread_load": true, "num_threads": 64}'
+                ),
+                "--hicache-mem-layout": "page_first_direct",
+                "--hicache-io-backend": "direct",
+            }
+        )
+        return server_args, env_vars
+
+
 class TestMooncakeBackendAccuracy(
     HiCacheStorageMooncakeBackendBaseMixin, CustomTestCase
 ):