From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yegor Yefremov Subject: Re: KS8695: possible NAPI issue Date: Fri, 5 Mar 2010 11:06:48 +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 ey-out-2122.google.com ([74.125.78.25]:48188 "EHLO ey-out-2122.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754287Ab0CEKGu convert rfc822-to-8bit (ORCPT ); Fri, 5 Mar 2010 05:06:50 -0500 Received: by ey-out-2122.google.com with SMTP id 25so571316eya.19 for ; Fri, 05 Mar 2010 02:06:49 -0800 (PST) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Fri, Mar 5, 2010 at 7:54 AM, figo zhang wrote: > 2010/3/4 Yegor Yefremov : >>>>> 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 develop= ment >>>>> host, after this transfer the network is not functioning i.e. no = pings >>>>> possible etc. >>>>> >>>>> To narrow down the problem I checked out this commit >>>>> >>>>> http://git.kernel.org/?p=3Dlinux/kernel/git/torvalds/linux-2.6.gi= t;a=3Dcommit;h=3D451f14439847db302e5104c44458b2dbb4b1829d. >>>>> Till here the network driver is functioning as intended, but afte= r >>>>> NAPI introduction I have this issue. With latest git-pull of "Lin= us' >>>>> 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 ether= net 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? >> >> Figo, 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.gi= t;a=3Dhistory;f=3Ddrivers/net/arm/ks8695net.c;h=3D2a7b7745cc55b54cefada= 690b0ea47865b54b6b9;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 ge= t >> desynchronized. >> >> Could you try the 2.6.33 or Linus tree? Thank you in advance. > > yes, i have test it on linux-2.6.33, it is work well. Thanks for testing. What kind of tests have you made? And with what dat= a amount? My tests look like following: 1. system start 2. ping one host: O.K. 3. nc -l -p 5000 > /var/test (about 1Mb): O.K. 4. ping the same host: failed and even if the fourth test succeeds, if I then send a file from other host the next ping or any other communication fails. I just tried to make some SSH sessions. It goes without a problem till I issue a ping after that. If I test the system with nuttcp I have no problem. Do you have any idea how to debug this? If I remove the NAPI support I have no problem with the same kernel and environment. I'd really like to get the whole stuff working. Regards, Yegor