From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yegor Yefremov Subject: Re: KS8695: possible NAPI issue Date: Wed, 3 Mar 2010 09:28:12 +0100 Message-ID: References: <4B8D1C02.1010204@softplc.com> <4B8DED29.9000605@softplc.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: figo zhang , netdev@vger.kernel.org, zealcook@gmail.com To: Dick Hollenbeck Return-path: Received: from mail-ew0-f220.google.com ([209.85.219.220]:52111 "EHLO mail-ew0-f220.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751831Ab0CCI2R convert rfc822-to-8bit (ORCPT ); Wed, 3 Mar 2010 03:28:17 -0500 Received: by ewy20 with SMTP id 20so769853ewy.21 for ; Wed, 03 Mar 2010 00:28:15 -0800 (PST) In-Reply-To: <4B8DED29.9000605@softplc.com> 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 developm= ent >>>> host, after this transfer the network is not functioning i.e. no p= ings >>>> 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 "Linu= s' >>>> 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= =2E30.5, >>> and except for this occasional loss of connection I get, the ethern= et >>> 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? >> > > Seems like a lot of work for me, given that my 2.6.30.5 kernel is mos= tly > working. =C2=A0 Yegor is having the problems on the newer kernels, ne= wer than > mine. =C2=A0Sounds like a warning flag to me, not an incentive. > > What is NAPI and why do I care? Here is Wikipedia article: http://en.wikipedia.org/wiki/NAPI The problem also is that I really need a kernel version not less than 2.6.33 because of the support of other platforms. I sniffed a little with wireshark and the symptoms are the following: after netcat transfer the system sends only ARP requests and no other p= ackets. I just git-pulled the latest Linus tree and the network still has the above described issues. =46igo, could you test the latest kernel with netcat transfers? So you could reproduce this behavior? Yegor