From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yegor Yefremov Subject: Re: KS8695: possible NAPI issue Date: Thu, 4 Mar 2010 11:10:37 +0100 Message-ID: References: <4B8D1C02.1010204@softplc.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Dick Hollenbeck , netdev@vger.kernel.org, zealcook@gmail.com To: figo zhang Return-path: Received: from mail-ew0-f220.google.com ([209.85.219.220]:38931 "EHLO mail-ew0-f220.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755217Ab0CDKKl convert rfc822-to-8bit (ORCPT ); Thu, 4 Mar 2010 05:10:41 -0500 Received: by ewy20 with SMTP id 20so1586494ewy.21 for ; Thu, 04 Mar 2010 02:10:40 -0800 (PST) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: >>> I'm using 2.6.33 kernel and I noticed such a strange behavior: >>> >>> after system start I transfer one file via netcat from my developme= nt >>> host, after this transfer the network is not functioning i.e. no pi= ngs >>> possible etc. >>> >>> To narrow down the problem I checked out this commit >>> >>> http://git.kernel.org/?p=3Dlinux/kernel/git/torvalds/linux-2.6.git;= a=3Dcommit;h=3D451f14439847db302e5104c44458b2dbb4b1829d. >>> Till here the network driver is functioning as intended, but after >>> NAPI introduction I have this issue. With latest git-pull of "Linus= ' >>> kernel tree" I can't even ping right after the systems start. >>> >>> Any Ideas? What am I missing? >>> >> >> No idea, although I am using the same ARM chip, my kernel is at 2.6.= 30.5, >> and except for this occasional loss of connection I get, the etherne= t driver >> seems to work better than what you are reporting. > > from linux-2.6.32, this ethernet =C2=A0driver have add NAPI support, = would > you like to > try using this version? =46igo, I just looked at the 2.6.32 kernel and found out that it doesn't' contain NAPI support (see the history http://git.kernel.org/?p=3Dlinux/kernel/git/stable/linux-2.6.32.y.git;a= =3Dhistory;f=3Ddrivers/net/arm/ks8695net.c;h=3D2a7b7745cc55b54cefada690= b0ea47865b54b6b9;hb=3DHEAD). So 2.6.33 is the first stable kernel to support NAPI. I made some further tests but I can't find the reason for network failures: the interrupts are coming and the packets will be received and sent so that rx/tx counters would be increased, but none of them seem to reach the IP stack. I don't know where and why the things get desynchronized. Could you try the 2.6.33 or Linus tree? Thank you in advance. Regards, Yegor