From mboxrd@z Thu Jan 1 00:00:00 1970 From: Li Yu Subject: Re: [PATCH net-next] rps: introduce a new sysctl switch rps_workaround_buggy_driver Date: Fri, 06 Apr 2012 10:07:09 +0800 Message-ID: <4F7E4FCD.7050501@gmail.com> References: <4F7D7464.7040503@gmail.com> <1333624027.18626.579.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev@vger.kernel.org To: Eric Dumazet Return-path: Received: from mail-iy0-f174.google.com ([209.85.210.174]:63052 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753496Ab2DFCHZ (ORCPT ); Thu, 5 Apr 2012 22:07:25 -0400 Received: by iagz16 with SMTP id z16so2548314iag.19 for ; Thu, 05 Apr 2012 19:07:24 -0700 (PDT) In-Reply-To: <1333624027.18626.579.camel@edumazet-glaptop> Sender: netdev-owner@vger.kernel.org List-ID: =E4=BA=8E 2012=E5=B9=B404=E6=9C=8805=E6=97=A5 19:07, Eric Dumazet =E5=86= =99=E9=81=93: > On Thu, 2012-04-05 at 18:31 +0800, Li Yu wrote: >> We encountered a buggy NIC driver or hardware/firmware, it keeps >> non-zero constant skb->rxhash for long time, so if we enabled RPS, >> the targeted CPU keeps same for long time too. >> >> This patch introduces a sysctl switch to workaround for such problem= , >> if the switch was on, RPS core discards the skb->rxhash that is >> computed by NIC hardware. >> >> Hope this patch also can help others, thanks. > > Really ? > > to disable this driver rxhash, you should try : > > ethtool -K eth0 rxhash off > > Great! I really did not know this new option ago, and wrote a kprobe workaround module. It seem that ethtool 2.6.39 have such support at least. Thank you very much! Yu > >