| Message ID | alpine.DEB.2.00.1001191308490.14108@wel-95.cs.helsinki.fi |
|---|---|
| State | RFC, archived |
| Delegated to: | David Miller |
| Headers | show |
On Tuesday 19 January 2010 13:17:51 you wrote: > On Tue, 19 Jan 2010, Denys Fedoryshchenko wrote: > > On Tuesday 19 January 2010 11:10:12 you wrote: > > > Hi, > > > thank you for testing. So srtt and rttvar is zero in any of those > > > cases. Ilpo, it is a bug in tcp_rtt_estimator then, I suppose? > > > > > > There is also a code comment in tcp_input.c, saying: > > > > * NOTE: clamping at TCP_RTO_MIN is not required, current algo > > > > * guarantees that rto is higher. > > > > > > So we either fix tcp_rtt_estimator or simply clamp at TCP_RTO_MIN? > > > > > > Damian > > > > > > > On Monday 11 January 2010 15:02:34 you wrote: > > > >> On Sat, 26 Dec 2009, Denys Fedoryshchenko wrote: > > > >>> Few more dumps. I notice: > > > >>> 1)Ack always equal 1 > > > >>> 2)It is usually first segment of data sent (?) > > > >>> > > > >>> Maybe some value not initialised properly? > > > >> > > > >> Can you see if the RTO lower bound is violated (I added some > > > >> printing of vars there too already now if it turns out to be > > > >> something): > > > >> > > > >> diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c > > > >> index 65b8ebf..d84469f 100644 > > > >> --- a/net/ipv4/tcp_ipv4.c > > > >> +++ b/net/ipv4/tcp_ipv4.c > > > > As i see in code it is rounding RTO to minimum value. > > It fixes my problem seems. > > > > Btw just a bit about my environment - wireless networks (sometimes > > lossy!) with low speed (128-512Kbps) customers working over pppoe. Maybe > > it will give a tip why rtt value is too low. > > What I find most strange in it is the fact that when it triggers for the > first time, the srtt and mdev are zero, not some value in between 0 and > 200ms. Therefore I suspect that this case might be something that we've > overlooked where srtt/mdev are not valid at all. > > Maybe the patch below helps... > Seems after this patch (and debug patch with warnings) my dmesg is clean. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 65b8ebf..c8166d7 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -401,6 +417,9 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info) * (see draft-zimmermann-tcp-lcd) */ if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH) break; + /* A bit too strict, just want to be on the safe side for now */ + if (sk->sk_state != TCP_ESTABLISHED) + break; if (seq != tp->snd_una || !icsk->icsk_retransmits || !icsk->icsk_backoff) break;