[UnifiedTree]: Sync sidecar component hits across TP ranks and make SWA prefetch all-or-nothing (#27264)

test/registered/radix_cache/unified_radix_tree/test_unified_radix_cache_kl_dsv4.py

@@ -1,5 +1,10 @@
+import os
+import shutil
+import tempfile
 import unittest
 
+from test_unified_radix_cache_kl_nightly import AccuracyTwoPassMixin
+
 from sglang.srt.utils import kill_process_tree
 from sglang.test.ci.ci_register import register_cuda_ci
 from sglang.test.kits.unified_radix_cache_kit import UnifiedRadixTreeTestMixin
@@ -100,5 +105,63 @@ class TestUnifiedDeepSeekV4FlashHiCachePageFirstDirect(
     hicache_mem_layout = "layer_first"
 
 
+# ─── DeepSeek V4 Flash + HiCache L3 (file backend) ──────────────────────
+
+
+class TestUnifiedDeepSeekV4FlashHiCacheL3(AccuracyTwoPassMixin, CustomTestCase):
+    """DeepSeek V4 Flash FP8 + HiCache L3 (file backend) + UnifiedRadixCache."""
+
+    @classmethod
+    def setUpClass(cls):
+        cls.model = DSV4_FLASH_MODEL
+        cls.base_url = DEFAULT_URL_FOR_TEST
+        cls.hicache_dir = tempfile.mkdtemp(prefix="hicache_l3_dsv4_")
+        cls.process = popen_launch_server(
+            cls.model,
+            cls.base_url,
+            timeout=DSV4_FLASH_LAUNCH_TIMEOUT,
+            other_args=[
+                "--trust-remote-code",
+                "--tp-size",
+                "4",
+                "--attention-backend",
+                "compressed",
+                "--page-size",
+                "256",
+                "--chunked-prefill-size",
+                "8192",
+                "--mem-fraction-static",
+                "0.9",
+                "--disable-shared-experts-fusion",
+                "--enable-hierarchical-cache",
+                "--hicache-ratio",
+                "2",
+                "--hicache-write-policy",
+                "write_through",
+                "--hicache-storage-prefetch-policy",
+                "wait_complete",
+                "--hicache-io-backend",
+                "direct",
+                "--hicache-mem-layout",
+                "page_first_direct",
+                "--hicache-storage-backend",
+                "file",
+                "--swa-full-tokens-ratio",
+                "0.25",
+            ],
+            env={
+                "SGLANG_DSV4_FP4_EXPERTS": "0",
+                "SGLANG_ENABLE_UNIFIED_RADIX_TREE": "1",
+                "SGLANG_HICACHE_FILE_BACKEND_STORAGE_DIR": cls.hicache_dir,
+            },
+        )
+
+    @classmethod
+    def tearDownClass(cls):
+        kill_process_tree(cls.process.pid)
+        if os.path.isdir(cls.hicache_dir):
+            shutil.rmtree(cls.hicache_dir, ignore_errors=True)
+
+
 if __name__ == "__main__":
     unittest.main()