Commit 135faae6 authored Jun 25, 2025 by Seth Forshee (DigitalOcean) Committed by Paolo Abeni Jul 03, 2025

bonding: don't force LACPDU tx to ~333 ms boundaries

The timer which ensures that no more than 3 LACPDUs are transmitted in
a second rearms itself every 333ms regardless of whether an LACPDU is
transmitted when the timer expires. This causes LACPDU tx to be delayed
until the next expiration of the timer, which effectively aligns LACPDUs
to ~333ms boundaries. This results in a variable amount of jitter in the
timing of periodic LACPDUs.

Change this to only rearm the timer when an LACPDU is actually sent,
allowing tx at any point after the timer has expired.

Signed-off-by: Seth Forshee (DigitalOcean) <sforshee@kernel.org>
Reviewed-by: Carlos Bilbao <carlos.bilbao@kernel.org>
Link: https://patch.msgid.link/20250625-fix-lacpdu-jitter-v1-1-4d0ee627e1ba@kernel.org

Signed-off-by: Paolo Abeni <pabeni@redhat.com>

parent 8b98f34c

drivers/net/bonding/bond_3ad.c

+6 −5

Original line number	Diff line number	Diff line
		@@ -1378,7 +1378,7 @@ static void ad_tx_machine(struct port *port)
		/* check if tx timer expired, to verify that we do not send more than
		* 3 packets per second
		*/
		if (port->sm_tx_timer_counter && !(--port->sm_tx_timer_counter)) {
		if (!port->sm_tx_timer_counter \|\| !(--port->sm_tx_timer_counter)) {
		/* check if there is something to send */
		if (port->ntt && (port->sm_vars & AD_PORT_LACP_ENABLED)) {
		__update_lacpdu_from_port(port);
		@@ -1393,14 +1393,15 @@ static void ad_tx_machine(struct port *port)
		* again until demanded
		*/
		port->ntt = false;
		}
		}
		/* restart tx timer(to verify that we will not exceed
		* AD_MAX_TX_IN_SECOND

		/* restart tx timer(to verify that we will not
		* exceed AD_MAX_TX_IN_SECOND
		*/
		port->sm_tx_timer_counter = ad_ticks_per_sec / AD_MAX_TX_IN_SECOND;
		}
		}
		}
		}

		/**
		* ad_periodic_machine - handle a port's periodic state machine