This patch updates the sending algorithm for roundrobin to avoid over-subscribing interface(s) when one or more interfaces in the bond is not able to send packets. This happened when order was not random and more than 2 interfaces were used.
Previously the algorithm would find the next available interface when an interface failed to send by, this means that most often it is current_interface + 1. The problem is that when the next packet is to be sent and the "normal" algorithm then continues with interface++ which then hits that same interface again. This patch updates the resending algorithm to update the global counter of the next interface to use. Example (prior to patch): Consider 6 x 100 Mbit/s interfaces in a rr bond. The normal order of links being used to send would look like: 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 ... If, for instance, interface 2 where unable to send the order would have been: 1 3 3 4 5 6 1 3 3 4 5 6 1 3 3 4 5 6 ... The resulting speed (for TCP) would then become: 50 + 0 + 100 + 50 + 50 + 50 = 300 Mbit/s instead of the expected 500 Mbit/s. If interface 3 also would fail the resulting speed would be half of the expected 400 Mbit/s (33 + 0 + 0 + 100 + 33 + 33). Signed-off-by: Lars Everbrand <lars.everbr...@protonmail.com> --- drivers/net/bonding/bond_main.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index e0880a3840d7..e02d9c6d40ee 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -4107,6 +4107,7 @@ static struct slave *bond_get_slave_by_id(struct bonding *bond, if (--i < 0) { if (bond_slave_can_tx(slave)) return slave; + bond->rr_tx_counter++; } } @@ -4117,6 +4118,7 @@ static struct slave *bond_get_slave_by_id(struct bonding *bond, break; if (bond_slave_can_tx(slave)) return slave; + bond->rr_tx_counter++; } /* no slave that can tx has been found */ return NULL; -- 2.29.2