T7066: VPP CPU workers should be calculated and verified

2 files changed, 41 insertions, 2 deletions

diff --git a/smoketest/scripts/cli/test_vpp.py b/smoketest/scripts/cli/test_vpp.py
index ba0d0d728..5e4832c00 100755
--- a/smoketest/scripts/cli/test_vpp.py
+++ b/smoketest/scripts/cli/test_vpp.py
@@ -940,6 +940,32 @@ class TestVPP(VyOSUnitTestSHIM.TestCase):
         for required_string in required_str_list:
             self.assertNotIn(required_string, out)
 
+    def test_11_vpp_cpu_settings(self):
+        main_core = '0'
+        workers = '2'
+
+        self.cli_set(base_path + ['settings', 'cpu', 'workers', workers])
+
+        # "cpu workers" reqiures main-core to be set
+        # expect raise ConfigError
+        with self.assertRaises(ConfigSessionError):
+            self.cli_commit()
+
+        self.cli_set(base_path + ['settings', 'cpu', 'main-core', main_core])
+
+        self.cli_commit()
+
+        config_entries = (
+            f'main-core {main_core}',
+            f'workers {workers}',
+            'dev 0000:00:00.0',
+        )
+
+        # Check configured options
+        config = read_file(VPP_CONF)
+        for config_entry in config_entries:
+            self.assertIn(config_entry, config)
+
 
 if __name__ == '__main__':
     unittest.main(verbosity=2)
diff --git a/src/conf_mode/vpp.py b/src/conf_mode/vpp.py
index 923ac7f31..7da40a21a 100755
--- a/src/conf_mode/vpp.py
+++ b/src/conf_mode/vpp.py
@@ -381,10 +381,22 @@ def verify(config):
     if 'cpu' in config['settings']:
         if (
             'corelist_workers' in config['settings']['cpu']
-            and 'main_core' not in config['settings']['cpu']
-        ):
+            or 'workers' in config['settings']['cpu']
+        ) and 'main_core' not in config['settings']['cpu']:
             raise ConfigError('"cpu main-core" is required but not set!')
 
+        cpus = int(get_core_count())
+        if 'workers' in config['settings']['cpu']:
+            # number of worker threads must be not more than
+            # available CPUs in the system - 2 (1 for main thread and at least 1 for system processes)
+            workers = int(config['settings']['cpu']['workers'])
+            available_workers = cpus - 2
+            if workers > available_workers:
+                raise ConfigError(
+                    f'The system does not have enough CPUs for {workers} VPP workers '
+                    f'(reduce to {available_workers} or less)'
+                )
+
     verify_memory(config['settings'])
 
     # Check if deleted interfaces are not xconnect memebrs
@@ -428,6 +440,7 @@ def generate(config):
 
 
 def apply(config):
+
     # Open persistent config
     # It is required for operations with interfaces
     persist_config = JSONStorage('vpp_conf')