ethernet: T4689: support asymetric RFS configuration on multiple interfaces

The initial implementation from commit ac4e07f9 ("rfs: T4689: Support RFS
(Receive Flow Steering)") always adjusted the global rps_sock_flow_entries
configuration. So if RFS was enabled for one NIC but not the other - it did not
work.

According to the documentation:

RFS is only available if the kconfig symbol CONFIG_RPS is enabled (on by
default for SMP). The functionality remains disabled until explicitly
configured. The number of entries in the global flow table is set through:

 /proc/sys/net/core/rps_sock_flow_entries

The number of entries in the per-queue flow table are set through:

 /sys/class/net/<dev>/queues/rx-<n>/rps_flow_cnt

Both of these need to be set before RFS is enabled for a receive queue. Values
for both are rounded up to the nearest power of two. The suggested flow count
depends on the expected number of active connections at any given time, which
may be significantly less than the number of open connections. We have found
that a value of 32768 for rps_sock_flow_entries works fairly well on a
moderately loaded server.

This commit sets rps_sock_flow_entries via sysctl on bootup leafing the RFS
configuration to the interface level.

3 files changed, 4 insertions, 13 deletions

diff --git a/python/vyos/ifconfig/ethernet.py b/python/vyos/ifconfig/ethernet.py
index b260a00ef..519cfc58c 100644
--- a/python/vyos/ifconfig/ethernet.py
+++ b/python/vyos/ifconfig/ethernet.py
@@ -70,13 +70,6 @@ class EthernetIf(Interface):
         },
     }}
 
-    _sysfs_set = {**Interface._sysfs_set, **{
-        'rfs': {
-            'convert': lambda num: num if num else '0',
-            'location': '/proc/sys/net/core/rps_sock_flow_entries',
-        },
-    }}
-
     def __init__(self, ifname, **kargs):
         super().__init__(ifname, **kargs)
         self.ethtool = Ethtool(ifname)
@@ -265,13 +258,11 @@ class EthernetIf(Interface):
 
     def set_rfs(self, state):
         rfs_flow = 0
-        global_rfs_flow = 0
         queues = len(glob(f'/sys/class/net/{self.ifname}/queues/rx-*'))
         if state:
             global_rfs_flow = 32768
             rfs_flow = int(global_rfs_flow/queues)
 
-        self.set_interface('rfs', global_rfs_flow)
         for i in range(0, queues):
             self._write_sysfs(f'/sys/class/net/{self.ifname}/queues/rx-{i}/rps_flow_cnt', rfs_flow)
 
diff --git a/smoketest/scripts/cli/test_interfaces_ethernet.py b/smoketest/scripts/cli/test_interfaces_ethernet.py
index 5049bd5b0..feb2c0268 100755
--- a/smoketest/scripts/cli/test_interfaces_ethernet.py
+++ b/smoketest/scripts/cli/test_interfaces_ethernet.py
@@ -205,7 +205,6 @@ class EthernetInterfaceTest(BasicInterfaceTest.TestCase):
         tmp = read_file(f'/proc/sys/net/core/rps_sock_flow_entries')
         self.assertEqual(int(tmp), global_rfs_flow)
 
-
         # delete configuration of RFS and check all values returned to default "0"
         for interface in self._interfaces:
             self.cli_delete(self._base_path + [interface, 'offload', 'rfs'])
@@ -219,9 +218,6 @@ class EthernetInterfaceTest(BasicInterfaceTest.TestCase):
                 tmp = read_file(f'/sys/class/net/{interface}/queues/rx-{i}/rps_flow_cnt')
                 self.assertEqual(int(tmp), 0)
 
-        tmp = read_file(f'/proc/sys/net/core/rps_sock_flow_entries')
-        self.assertEqual(int(tmp), 0)
-
 
     def test_non_existing_interface(self):
         unknonw_interface = self._base_path + ['eth667']
diff --git a/src/etc/sysctl.d/30-vyos-router.conf b/src/etc/sysctl.d/30-vyos-router.conf
index 4feb7e09a..411429510 100644
--- a/src/etc/sysctl.d/30-vyos-router.conf
+++ b/src/etc/sysctl.d/30-vyos-router.conf
@@ -109,3 +109,7 @@ net.ipv4.neigh.default.gc_thresh3 = 8192
 net.ipv6.neigh.default.gc_thresh1 = 1024
 net.ipv6.neigh.default.gc_thresh2 = 4096
 net.ipv6.neigh.default.gc_thresh3 = 8192
+
+# Enable global RFS (Receive Flow Steering) configuration. RFS is inactive
+# until explicitly configured at the interface level
+net.core.rps_sock_flow_entries = 32768