From 5086d9a9dfec4866806da303115489b0606decb7 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 11 Nov 2022 13:47:35 +0000 Subject: rxrpc: Move the cwnd degradation after transmitting packets When we've gone for >1RTT without transmitting a packet, we should reduce the ssthresh and cut the cwnd by half (as suggested in RFC2861 sec 3.1). However, we may receive ACK packets in a batch and the first of these may cut the cwnd, preventing further transmission, and each subsequent one cuts the cwnd yet further, reducing it to the floor and killing performance. Fix this by moving the cwnd reset to after doing the transmission and resetting the base time such that we don't cut the cwnd by half again for at least another RTT. Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org --- net/rxrpc/call_event.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'net/rxrpc/call_event.c') diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c index 9f1e490ab976..fd122e3726bd 100644 --- a/net/rxrpc/call_event.c +++ b/net/rxrpc/call_event.c @@ -427,6 +427,13 @@ void rxrpc_input_call_event(struct rxrpc_call *call, struct sk_buff *skb) rxrpc_transmit_some_data(call); + if (skb) { + struct rxrpc_skb_priv *sp = rxrpc_skb(skb); + + if (sp->hdr.type == RXRPC_PACKET_TYPE_ACK) + rxrpc_congestion_degrade(call); + } + if (test_and_clear_bit(RXRPC_CALL_EV_INITIAL_PING, &call->events)) rxrpc_send_initial_ping(call); -- cgit v1.2.3