Return-path: Received: from one.firstfloor.org ([213.235.205.2]:44439 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751312AbZAEQWH (ORCPT ); Mon, 5 Jan 2009 11:22:07 -0500 Date: Mon, 5 Jan 2009 17:35:53 +0100 From: Andi Kleen To: Felix Fietkau Cc: Andi Kleen , Larry Finger , Michael Buesch , linux-wireless@vger.kernel.org, John Linville Subject: Re: rate instability in wireless stack Message-ID: <20090105163553.GU496@one.firstfloor.org> (sfid-20090105_172211_516282_20988E83) References: <20090105025302.GF496@one.firstfloor.org> <49618497.50809@lwfinger.net> <20090105050248.GG496@one.firstfloor.org> <496193A6.3040608@lwfinger.net> <20090105054830.GJ496@one.firstfloor.org> <49620BE5.9030507@openwrt.org> <20090105142343.GS496@one.firstfloor.org> <49621C36.70602@openwrt.org> <20090105152410.GT496@one.firstfloor.org> <49622686.9050005@openwrt.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <49622686.9050005@openwrt.org> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Mon, Jan 05, 2009 at 04:25:58PM +0100, Felix Fietkau wrote: > > Forcing the rates works somewhat, but the link quality is very poor > > (10-15/100) and fluctuates. > Another possibility is that the tx power is fine, but the > sensitivity of the card is crap, so the packets actually make it, Ok, but I see the same thing with two different cards, with different chipsets (RaLink and RealTek). You think they both have that problem? > Even if both cards work fine on Windows, I wouldn't assume that this > is an issue with mac80211. The information that was used to write > these two drivers was derived from very poor vendor codebases and > limited information in datasheets, so it's much more likely that > simply the Baseband/RF tuning is far from optimal on both cards. Ok I won't try then. Setting up Windows would be quite a lot of effort and I would prefer to avoid it. > Maybe we can see more if you provide some minstrel stats after > you've pushed more traffic through the link - 25-50 packets is not > nearly enough for getting an accurate view of how good the link is. > Try to push through a few megabytes of data... Here are the statistics after a few MB. rate throughput ewma prob this prob this succ/attempt success attempts TtP 1 0.9 97.9 100.0 1( 1) 19284 21249 2 0.0 0.0 0.0 0( 0) 0 101 5.5 0.0 0.0 0.0 0( 0) 0 104 11 0.0 0.0 0.0 0( 0) 253 397 6 0.0 0.0 0.0 0( 0) 0 103 9 0.0 0.0 0.0 0( 0) 0 106 12 0.0 0.0 0.0 0( 0) 0 107 18 0.0 0.0 0.0 0( 0) 0 104 24 0.0 0.0 0.0 0( 0) 0 111 36 0.0 0.0 0.0 0( 0) 0 120 48 0.0 0.0 0.0 0( 0) 0 179 54 0.0 0.0 0.0 0( 0) 0 253 Total packet count:: ideal 9023 lookaround 474 -Andi -- ak@linux.intel.com