scripts/perftune.py: add support for tweaking VLAN interfaces

Handle VLAN interfaces similar to bond ones: discover the underlying physical
devices and tweak them.

Fixes scylladb#765

scripts/perftune.py

@@ -576,9 +576,10 @@ def __init__(self, args):
         self.nics=args.nics
 
         self.__nic_is_bond_iface = NetPerfTuner.__get_bond_ifaces()
+        self.__nic_is_vlan_iface = NetPerfTuner.__get_vlan_ifaces()
         self.__slaves = self.__learn_slaves()
 
-        # check that self.nics contain a HW device or a bonding interface
+        # check that self.nics contain a HW device or a supported composite interface
         self.__check_nics()
 
         # Fetch IRQs related info
@@ -595,8 +596,8 @@ def tune(self):
                 perftune_print("Setting a physical interface {}...".format(nic))
                 self.__setup_one_hw_iface(nic)
             else:
-                perftune_print("Setting {} bonding interface...".format(nic))
-                self.__setup_bonding_iface(nic)
+                perftune_print(f"Setting a {nic} {'bond' if self.nic_is_bond_iface(nic) else 'VLAN'} interface...")
+                self.__setup_composite_iface(nic)
 
         # Increase the socket listen() backlog
         fwriteln_and_log('/proc/sys/net/core/somaxconn', '4096')
@@ -608,6 +609,12 @@ def tune(self):
     def nic_is_bond_iface(self, nic):
         return self.__nic_is_bond_iface.get(nic, False)
 
+    def nic_is_vlan_iface(self, nic):
+        return self.__nic_is_vlan_iface.get(nic, False)
+
+    def nic_is_composite_iface(self, nic):
+        return self.nic_is_bond_iface(nic) or self.nic_is_vlan_iface(nic)
+
     def nic_exists(self, nic):
         return self.__iface_exists(nic)
 
@@ -617,8 +624,8 @@ def nic_is_hw_iface(self, nic):
     def slaves(self, nic):
         """
         Returns an iterator for all slaves of the nic.
-        If agrs.nic is not a bonding interface an attempt to use the returned iterator
-        will immediately raise a StopIteration exception - use __dev_is_bond_iface() check to avoid this.
+        If agrs.nic is not a composite interface an attempt to use the returned iterator
+        will immediately raise a StopIteration exception - use nic_is_composite_iface() check to avoid this.
         """
         return iter(self.__slaves[nic])
 
@@ -646,7 +653,7 @@ def __check_nics(self):
         for nic in self.nics:
             if not self.nic_exists(nic):
                 raise Exception("Device {} does not exist".format(nic))
-            if not self.nic_is_hw_iface(nic) and not self.nic_is_bond_iface(nic):
+            if not self.nic_is_hw_iface(nic) and not self.nic_is_composite_iface(nic):
                 raise Exception("Not supported virtual device {}".format(nic))
 
     def __get_irqs_one(self, iface):
@@ -744,24 +751,44 @@ def __get_bond_ifaces():
 
         return bond_dict
 
+    @staticmethod
+    def __get_vlan_ifaces():
+        # Each VLAN interface is going to have a corresponding entry in /proc/net/vlan/ directory
+        return {pathlib.PurePath(pathlib.Path(f)).name: True
+                for f in filter(lambda vlan_name: vlan_name != "/proc/net/vlan/config", glob.glob("/proc/net/vlan/*"))}
+
     def __learn_slaves_one(self, nic):
         """
         Learn underlying physical devices a given NIC
 
         :param nic: An interface to search slaves for
         """
         slaves_list = set()
+        top_slaves_list = set()
 
         if self.nic_is_bond_iface(nic):
             top_slaves_list = set(itertools.chain.from_iterable(
                 [line.split() for line in open("/sys/class/net/{}/bonding/slaves".format(nic), 'r').readlines()]))
-
-            # Slaves can be themselves bonded devices: let's descend (DFS) all the way down to get physical devices
-            for s in top_slaves_list:
-                if self.nic_is_bond_iface(s):
-                    slaves_list |= self.__learn_slaves_one(s)
-                else:
-                    slaves_list.add(s)
+        elif self.nic_is_vlan_iface(nic):
+            # VLAN interfaces have a symbolic link 'lower_<parent_interface_name>' under
+            # /sys/class/net/<VLAN interface name>.
+            #
+            # For example:
+            #
+            # lrwxrwxrwx  1 root root    0 Jul  5 18:38 lower_eno1 -> ../../../pci0000:00/0000:00:1f.6/net/eno1/
+            #
+            top_slaves_list = set([pathlib.PurePath(pathlib.Path(f).resolve()).name
+                                   for f in glob.glob(f"/sys/class/net/{nic}/lower_*")])
+
+        # Slaves can be themselves bond or VLAN devices: let's descend (DFS) all the way down to get physical devices.
+        # Bond slaves can't be VLAN interfaces but VLAN interface parent device can be a bond interface.
+        # Bond slaves can also be bonds.
+        # For simplicity let's not discriminate.
+        for s in top_slaves_list:
+            if self.nic_is_composite_iface(s):
+                slaves_list |= self.__learn_slaves_one(s)
+            else:
+                slaves_list.add(s)
 
         return slaves_list
 
@@ -972,7 +999,7 @@ def __learn_irqs(self):
         """
         nic_irq_dict={}
         for nic in self.nics:
-            if self.nic_is_bond_iface(nic):
+            if self.nic_is_composite_iface(nic):
                 for slave in filter(self.__dev_is_hw_iface, self.slaves(nic)):
                     nic_irq_dict[slave] = self.__learn_irqs_one(slave)
             else:
@@ -1064,7 +1091,11 @@ def __setup_one_hw_iface(self, iface):
         self.__setup_rps(iface, self.cpu_mask)
         self.__setup_xps(iface)
 
-    def __setup_bonding_iface(self, nic):
+    def __setup_composite_iface(self, nic):
+        """
+        Set up the interface which is a bond or a VLAN interface
+        :param nic: name of a composite interface to set up
+        """
         for slave in self.slaves(nic):
             if self.__dev_is_hw_iface(slave):
                 perftune_print("Setting up {}...".format(slave))