Return-path: Received: from mail-ew0-f46.google.com ([209.85.215.46]:35166 "EHLO mail-ew0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751633Ab0GUWRT convert rfc822-to-8bit (ORCPT ); Wed, 21 Jul 2010 18:17:19 -0400 Received: by ewy23 with SMTP id 23so2666151ewy.19 for ; Wed, 21 Jul 2010 15:17:15 -0700 (PDT) MIME-Version: 1.0 Date: Thu, 22 Jul 2010 00:17:12 +0200 Message-ID: Subject: ath9k: performance regressions / tx semi-stuck somehow From: =?ISO-8859-1?Q?Bj=F6rn_Smedman?= To: ath9k-devel@lists.ath9k.org, linux-wireless Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-wireless-owner@vger.kernel.org List-ID: Hi all, I just tried out compat-wireless-2010-07-16 on AR913x (with openwrt/trunk@r22321) and saw some weird performance problems. First, with the default 11n HT20 AP configuration I get really good performance on an old 11g MacBook. 16Mbps downloads limited by WAN. :) But then I try a newer 11n MacBook and performance absolutely sucks. 2-3Mbps downloads with erratic bursts and "hangs". So, I start to think something is wrong with 11n and reconfigure for 11g only. Then the 11g MacBook performance also sucks. The same 2-3Mbps downloads with erratic bursts and "hangs". So 11n AP and 11g client is good, but 11g AP and 11g client sucks. Looking at the rc_stats it seems like tx completely breaks down from time to time: root@OpenWrt:/sys/kernel/debug/ieee80211/phy0# cat stations/00\:17\:f2\:51\:b2\: 2d/rc_stats rate throughput ewma prob this prob this succ/attempt success attempts t 1 0.1 18.3 0.0 0( 19) 28 731 2 0.0 0.0 0.0 0( 0) 0 18 5.5 0.0 0.0 0.0 0( 0) 0 10 11 0.0 0.0 0.0 0( 0) 0 14 6 0.0 0.0 0.0 0( 0) 0 11 9 0.0 0.0 0.0 0( 0) 0 18 12 0.0 0.0 0.0 0( 0) 0 12 18 0.0 0.0 0.0 0( 0) 0 16 24 0.0 0.0 0.0 0( 0) 0 18 36 0.1 0.4 0.0 0( 0) 2 1824 48 0.0 0.0 0.0 0( 2) 0 16 T P 54 27.3 63.1 0.0 0(180) 4749 13896 Total packet count:: ideal 4780 lookaround 532 That's in exactly the same spot I was getting 16Mbps consistently with AP was 11n! Any debuging I can do to help? Bisecting is unfortunately a lot of work on this embedded system... /Bj?rn