Hello! > This is where things start going bad. The window starts shrinking from > 15340 all the way down to 2355 over the course of 0.3 seconds. Notice the > many duplicate acks that serve no purpose These are not duplicate, TCP_NODELAY sender just starts flooding tiny segments, and those are normal ACKs acking those segments, note ACK field is not the same. > Five minutes later the TCP window is still at 2355, .... > We are kind of stumped at this point, and it's proving to be a > show-stopping bug for our purposes, especially over WAN links that have > higher latency (for obvious reasons). Any kind of assistance would be > greatly appreciated. I still do not know how the value of 184 is possible in your case, I would expect 730 as an absolute possible minumum. I see 9420 (2355*4). Anyway, ignoring this puzzle, the following patch for 2.4 should help. --- net/ipv4/tcp_input.c.orig 2003-02-20 20:38:39.000000000 +0300 +++ net/ipv4/tcp_input.c 2005-09-02 22:28:00.845952888 +0400 @@ -343,8 +343,6 @@ app_win -= tp->ack.rcv_mss; app_win = max(app_win, 2U*tp->advmss); - if (!ofo_win) - tp->window_clamp = min(tp->window_clamp, app_win); tp->rcv_ssthresh = min(tp->window_clamp, 2U*tp->advmss); } } - : send the line "unsubscribe linux-net" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
