Return-path: Received: from mail.ultra-3eti.com ([173.13.207.162]:41177 "EHLO mail.ultra-3eti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751478Ab2LJT2M convert rfc822-to-8bit (ORCPT ); Mon, 10 Dec 2012 14:28:12 -0500 From: Chaoxing Lin To: Thomas Pedersen CC: Georgiewskiy Yuriy , "linux-wireless@vger.kernel.org" , open11s Subject: RE: help: 802.11s bad performance with 802.11n enabled Date: Mon, 10 Dec 2012 19:28:08 +0000 Message-ID: (sfid-20121210_202816_000541_EB5AD91F) References: In-Reply-To: Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: > 4. 802.11n packet aggregation. I believe this is the main problem by > the fact that, disabling 802.11n packet aggregation in ath9k driver > will make the network stable and problem 2 and 3 are not seen. In > other words, problem 2 and 3 may be caused by aggregation (my > imagination, aggregation caused certain error condition that is not > handled properly, which triggers problem 2 and 3) TP> And to reproduce you run a simultaneous ping from one node to ~6 others? It will take me a few days to find time to reproduce this, so any interesting observations you can offer in the mean time would be helpful. Yes, I run simultaneous ping from one node to all other 6 nodes. No, when 802.11n is enabled, the ping loss is seen fairly fast (in a few minutes). Problem 2 and problem 3 is not that predictable. But once it's in that state, it stucks there and give me enough time to troubleshoot. I post test result of test running a few days just to show that disabling 802.11n really make the network stable, instead of "stable by chance in a short period.