Return-path: Received: from mail-gx0-f16.google.com ([209.85.217.16]:58977 "EHLO mail-gx0-f16.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752449AbYIWTWw (ORCPT ); Tue, 23 Sep 2008 15:22:52 -0400 Received: by gxk9 with SMTP id 9so4797575gxk.13 for ; Tue, 23 Sep 2008 12:22:51 -0700 (PDT) Message-ID: <43e72e890809231222r21396433j88074d5514ef56f0@mail.gmail.com> (sfid-20080923_212257_525629_4765572A) Date: Tue, 23 Sep 2008 12:22:51 -0700 From: "Luis R. Rodriguez" To: "Steven Noonan" Subject: Re: [ath9k-devel] ath9k: massive unexplained latency in 2.6.27 (rc5, rc6, probably others) Cc: linux-wireless , LKML , "Senthilkumar Balasubramanian" , "ath9k-devel@lists.ath9k.org" , "Luis Rodriguez" , "Johannes Berg" , "Ingo Molnar" In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 References: <43e72e890809201426x61c94bfej2dcda1c178be81b@mail.gmail.com> <20080922065453.GD19580@tesla> <20080922080632.GA20446@tesla> <43e72e890809220901y162636fu63ed133f0a0c235@mail.gmail.com> Sender: linux-wireless-owner@vger.kernel.org List-ID: 2008/9/23 Steven Noonan : > Okay. I'm in Seattle now. > > Yes, it solved the issue, but surely an #if 0 isn't a proper solution. For 2.6.27 it will be unless people are willing to accept a patch to enable ANI support for 2.6.27. > What's the actual bug here? I'm afraid the meaning of what's going on > here isn't exactly intuitive. Check linux-wireless for my patch on MIB event comments. But I'll summarize here for you. We get MIB interrupts to update statistics on a number of PHY related elements. We then use this information to process ANI -- some automatic noise immunity work. If you don't process the information for ANI it seems you get the hardware treating this as untreated and hence you get an interrupt storm. So since 2.6.27 doesn't have ANI implemented the MIB interrupts are not useful except to collect internal statistics. Since you are so eager to test this with a "proper" solution I will send you a patch to test ANI for 2.6.27. We'll leave it up to the maintainers and distributions to decide whether or not to pick this up. But for that let's leave that for another thread. Luis