[tests/route]: Add an option to test max ASIC route scale limit (#8265)

What is the motivation for this PR?
To improve route scaling tests and avoid table full errors in production

How did you do it?
Increase test scale based on topology and check for certain necessary config parameters

How did you verify/test it?
By running this sonic-mgmt on testbeds with different topologies

Author: prabhataravind

tests/route/conftest.py

@@ -10,6 +10,9 @@ def pytest_addoption(parser):
     route_group.addoption("--num_routes", action="store", default=None, type=int,
                           help="Number of routes for add/delete")
 
+    route_group.addoption("--max_scale", action="store_true",
+                          help="Test with maximum possible route scale")
+
 
 @pytest.fixture(scope='module')
 def get_function_conpleteness_level(pytestconfig):

tests/route/test_route_perf.py

@@ -22,7 +22,46 @@
 
 ROUTE_TABLE_NAME = "ASIC_STATE:SAI_OBJECT_TYPE_ROUTE_ENTRY"
 DEFAULT_NUM_ROUTES = 10000
-DEAFULT_M0_MX_NUM_ROUTES = 500
+
+route_scale_per_role = {
+    "m0": {
+        "ipv4": 500,
+        "ipv6": 500
+    },
+    "mx": {
+        "ipv4": 500,
+        "ipv6": 500
+    },
+    "t0": {
+        "ipv4": 40000,
+        "ipv6": 8000
+    },
+    "t1": {
+        "ipv4": 40000,
+        "ipv6": 8000
+    }
+}
+
+
+def get_route_scale_per_role(tbinfo, ip_version):
+    topo_name = tbinfo["topo"]["name"].split('-', 1)[0]
+    logger.info("Test topology: {}".format(topo_name))
+    if topo_name in route_scale_per_role:
+        set_num_routes = route_scale_per_role[topo_name][ip_version]
+    else:
+        set_num_routes = DEFAULT_NUM_ROUTES
+    return set_num_routes
+
+
+@pytest.fixture
+def check_config(duthosts, enum_rand_one_per_hwsku_frontend_hostname):
+    duthost = duthosts[enum_rand_one_per_hwsku_frontend_hostname]
+    asic = duthost.facts["asic_type"]
+
+    if (asic == "broadcom"):
+        alpm_enable = duthost.command('bcmcmd "conf show l3_alpm_enable"')["stdout_lines"][2].strip()
+        logger.info("Checking config: {}".format(alpm_enable))
+        pytest_assert(alpm_enable == "l3_alpm_enable=2", "l3_alpm_enable is not set for route scaling")
 
 
 @pytest.fixture(autouse=True)
@@ -276,19 +315,19 @@ def test_perf_add_remove_routes(
     ptfadapter,
     enum_rand_one_per_hwsku_frontend_hostname,
     request,
+    check_config,
     ip_versions,
     enum_rand_one_frontend_asic_index,
 ):
     duthost = duthosts[enum_rand_one_per_hwsku_frontend_hostname]
     asichost = duthost.asic_instance(enum_rand_one_frontend_asic_index)
+    max_scale = request.config.getoption("--max_scale")
     # Number of routes for test
     set_num_routes = request.config.getoption("--num_routes")
-    if set_num_routes is None:
-        topo_name = tbinfo["topo"]["name"]
-        if topo_name in ["m0", "mx"]:
-            set_num_routes = DEAFULT_M0_MX_NUM_ROUTES
-        else:
-            set_num_routes = DEFAULT_NUM_ROUTES
+    if max_scale and set_num_routes is not None:
+        raise Exception("--max_scale and --num_routes are mutually exclusive")
+    elif not max_scale and set_num_routes is None:
+        set_num_routes = get_route_scale_per_role(tbinfo, "ipv{}".format(ip_versions))
 
     # Generate interfaces and neighbors
     NUM_NEIGHS = 50  # Update max num neighbors for multi-asic
@@ -310,7 +349,10 @@ def test_perf_add_remove_routes(
         ),
     )
 
-    num_routes = min(avail_routes_count, set_num_routes)
+    if (max_scale):
+        num_routes = avail_routes_count
+    else:
+        num_routes = min(avail_routes_count, set_num_routes)
     logger.info(
         "IP route utilization before test start: Used: {}, Available: {}, Test count: {}".format(
             used_routes_count, avail_routes_count, num_routes