From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: Packet time delays on multi-core systems Date: Fri, 01 Oct 2010 14:59:26 +0200 Message-ID: <1285937966.2641.117.camel@edumazet-laptop> References: <20100929191851.GC86786@beaver.vrungel.ru> <1285796721.5211.156.camel@edumazet-laptop> <20100930062419.GD86786@beaver.vrungel.ru> <1285828432.5211.812.camel@edumazet-laptop> <20100930122321.GA1575@beaver.vrungel.ru> <1285850669.2615.426.camel@edumazet-laptop> <20100930173732.GB4094@beaver.vrungel.ru> <1285869782.2615.920.camel@edumazet-laptop> <20100930181556.GC4094@beaver.vrungel.ru> <1285872765.2615.1008.camel@edumazet-laptop> <20101001101650.GD4094@beaver.vrungel.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Linux Kernel Mailing List , netdev To: Alexey Vlasov Return-path: Received: from mail-fx0-f46.google.com ([209.85.161.46]:53558 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932466Ab0JAM7d (ORCPT ); Fri, 1 Oct 2010 08:59:33 -0400 In-Reply-To: <20101001101650.GD4094@beaver.vrungel.ru> Sender: netdev-owner@vger.kernel.org List-ID: Le vendredi 01 octobre 2010 =C3=A0 14:16 +0400, Alexey Vlasov a =C3=A9c= rit : > I have also found that: > 1. rx overruns is increasing. > 2. rx_queue_drop_packet_count is increasing. So you flood machine with packets, its not an idle one ? I thought you were doing experiments with light trafic. > # ethtool -S eth0 | grep drop > tx_dropped: 0 > rx_queue_drop_packet_count: 1260743751 > dropped_smbus: 0 > rx_queue_0_drops: 0 > rx_queue_1_drops: 0 > rx_queue_2_drops: 0 > rx_queue_3_drops: 0 >=20 ethtool -S eth0 (full output, not small parts) > 3. By sending SYN-packets by hping, RST packet doesn't send, but I do= n't know may=20 > be it is just some feature in 2.6.32. > newbox # hping -c 1 -S -p 80 111.111.111.111 > HPING 111.111.111.111 (eth0 111.111.111.111): S set, 40 headers + 0 d= ata bytes > len=3D46 ip=3D111.111.111.111 ttl=3D58 DF id=3D11471 sport=3D80 flags= =3DSA seq=3D0 win=3D65535 rtt=3D99.0 ms >=20 > --- 111.111.111.111 hping statistic --- > 1 packets tramitted, 1 packets received, 0% packet loss > round-trip min/avg/max =3D 99.0/99.0/99.0 ms >=20 > 13:59:07.439528 IP newbox.2777 > 111.111.111.111.80: S 345595033:3455= 95033(0) win 512 > 13:59:07.439626 IP 111.111.111.111.80 > newbox.2777: S 1178827395:117= 8827395(0) ack 345595034 win 65535 > 13:59:10.439368 IP 111.111.111.111.80 > newbox.2777: S 1178827395:117= 8827395(0) ack 345595034 win 65535 > 13:59:16.439313 IP 111.111.111.111.80 > newbox.2777: S 1178827395:117= 8827395(0) ack 345595034 win 65535 > 13:59:28.439206 IP 111.111.111.111.80 > newbox.2777: S 1178827395:117= 8827395(0) ack 345595034 win 65535 >=20 > As a result I got doubles: Are you playing with trafic shaping ? tc -s -d qdisc > DUP! len=3D46 ip=3D111.111.111.111 ttl=3D58 DF id=3D27454 sport=3D80 = flags=3DSA seq=3D0 win=3D65535 rtt=3D3137.8 ms >=20 > Example of another TCP-session from 2.6.28 kernel: > oldbox # hping -c 1 -S -p 80 111.111.111.111 > HPING 111.111.111.111 (eth0 111.111.111.111): S set, 40 headers + 0 d= ata bytes > len=3D46 ip=3D111.111.111.111 ttl=3D58 DF id=3D53180 sport=3D80 flags= =3DSA seq=3D0 win=3D65535 rtt=3D2.9 ms >=20 > --- 111.111.111.111 hping statistic --- > 1 packets tramitted, 1 packets received, 0% packet loss > round-trip min/avg/max =3D 2.9/2.9/2.9 ms >=20 > 14:01:45.225136 IP oldbox.2776 > 111.111.111.111.80: S 1983626200:198= 3626200(0) win 512 > 14:01:45.225288 IP 111.111.111.111.80 > oldbox.2776: S 3796385036:379= 6385036(0) ack 1983626201 win 65535 > 14:01:45.227990 IP oldbox.2776 > 111.111.111.111.80: R 1983626201:198= 3626201(0) win 0 >=20