From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: bnx2 udp multicast packet loss and jtter Date: Fri, 17 Jun 2011 17:52:44 +0200 Message-ID: <1308325964.3539.14.camel@edumazet-laptop> References: <1308324641.3539.1.camel@edumazet-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev@vger.kernel.org To: Kieran Kunhya Return-path: Received: from mail-ww0-f44.google.com ([74.125.82.44]:62269 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759190Ab1FQPws (ORCPT ); Fri, 17 Jun 2011 11:52:48 -0400 Received: by wwe5 with SMTP id 5so604488wwe.1 for ; Fri, 17 Jun 2011 08:52:47 -0700 (PDT) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: Le vendredi 17 juin 2011 =C3=A0 16:35 +0100, Kieran Kunhya a =C3=A9crit= : > On Fri, Jun 17, 2011 at 4:30 PM, Eric Dumazet wrote: > > > > Le samedi 11 juin 2011 =C3=A0 15:32 +0100, Kieran Kunhya a =C3=A9cr= it : > > > Hello, > > > > > > I get some bad packet loss and high jitter on a BCM5709. This is = on > > > kernel 2.6.38-8 - unfortunately using a newer kernel isn't an opt= ion > > > right now. > > > The bnx2 driver is version v2.0.23b. > > > > > > I've tried a lot of kenel types such as -lowlatency, -ck and vani= lla. > > > The thread doing the udp output is at realtime priority and the s= ame > > > thing happens with different applications. > > > > > > Example of jitter > > > http://dl.dropbox.com/u/2701213/jitter.png > > > > > > Is there anything I can do to further diagnose this problem? > > > > > > > Hi > > > > How is this jitter measured ? > > > > Is the link otherwise idle, or do you have a particular qdisc setup= to > > make sure packets from other flow wont have an effect ? >=20 > Thanks for the reply. > The jitter is measured with an IPTV analyser. There are other devices > on the same switch which don't have any jitter issues. > The link is otherwise idle. jitter has a precise meaning in RTP flows. Is this IPTV analyser using this definition ? Is this analyser running on the machine that sends frames, or another machine ? Are you sure the realtime thread fullfill its requirements ? (RT priority wont help if this thread is cpu bounded)