Add ZMQ IPv6 support, bench_serving sampling params, and reduce routed_dp_rank log noise (#27180)

Co-authored-by: Hanming Lu <69857889+hanming-lu@users.noreply.github.com>
Co-authored-by: Grigory Sizov <grisha.sizov@gmail.com>

test/registered/utils/test_network_address.py

@@ -3,7 +3,7 @@ import unittest
 from unittest.mock import patch
 
 from sglang.srt.server_args import PortArgs, ServerArgs
-from sglang.srt.utils.network import NetworkAddress
+from sglang.srt.utils.network import NetworkAddress, is_zmq_endpoint_ipv6
 from sglang.test.ci.ci_register import register_cpu_ci
 
 register_cpu_ci(est_time=7, suite="base-a-test-cpu")
@@ -180,6 +180,22 @@ class TestNetworkAddressParseErrors(unittest.TestCase):
             NetworkAddress.parse(":8000")
 
 
+class TestZmqEndpointIPv6(unittest.TestCase):
+    def test_bracketed_ipv6_endpoint(self):
+        self.assertTrue(is_zmq_endpoint_ipv6("tcp://[::1]:30000"))
+        self.assertTrue(is_zmq_endpoint_ipv6("tcp://[2001:db8::1]:30000"))
+
+    def test_non_ipv6_endpoints(self):
+        self.assertFalse(is_zmq_endpoint_ipv6("tcp://127.0.0.1:30000"))
+        self.assertFalse(is_zmq_endpoint_ipv6("tcp://localhost:30000"))
+        self.assertFalse(is_zmq_endpoint_ipv6("ipc:///tmp/sglang.sock"))
+
+    def test_malformed_or_non_tcp_endpoints(self):
+        self.assertFalse(is_zmq_endpoint_ipv6("tcp://[not-ipv6]:30000"))
+        self.assertFalse(is_zmq_endpoint_ipv6("tcp://[::1:30000"))
+        self.assertFalse(is_zmq_endpoint_ipv6("ipc://[::1]:30000"))
+
+
 class TestNetworkAddressBracketStripping(unittest.TestCase):
     def test_strip_brackets(self):
         na = NetworkAddress("[::1]", 8000)