From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from smtp3.Stanford.EDU ([171.67.20.26]:39099 "EHLO smtp3.stanford.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753980AbYD3SIp (ORCPT ); Wed, 30 Apr 2008 14:08:45 -0400 Received: from smtp3.stanford.edu (localhost.localdomain [127.0.0.1]) by localhost (Postfix) with SMTP id 7284060EF39 for ; Wed, 30 Apr 2008 11:00:55 -0700 (PDT) Received: from localhost (DNab42390a.Stanford.EDU [171.66.57.10]) by smtp3.stanford.edu (Postfix) with ESMTP id 62B1660E213 for ; Wed, 30 Apr 2008 11:00:53 -0700 (PDT) Date: Wed, 30 Apr 2008 11:00:53 -0700 From: Gautam Iyer To: linux-wireless@vger.kernel.org Subject: Re: b43 reduced performance in Linux-2.6.25 Message-ID: <20080430180053.GA21403@stanford.edu> (sfid-20080430_200837_020891_A0F5696C) References: <20080429215629.GC17790@stanford.edu> <4817A28E.2050309@lwfinger.net> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="YiEDa0DAkWCtVeE4" In-Reply-To: <4817A28E.2050309@lwfinger.net> Sender: linux-wireless-owner@vger.kernel.org List-ID: --YiEDa0DAkWCtVeE4 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Apr 29, 2008 at 05:34:54PM -0500, Larry Finger wrote: >> I saw a few threads about reduced performance in b43 in the 2.6.24 / >> 2.6.25_rcXX kernels, but couldn't manage to fix the problem myself: >> On my system, using ndiswrapper and the windows drivers gives me about >> 1.5 times the performance of the in kernel b43 drivers. >> Here are my system specs: >> Broadcom Corporation BCM4312 802.11a/b/g [14e4:4312] (rev 02) >> Linux 2.6.25 (gentoo-sources-2.6.25-r1). >> b43 wireless driver with firmware 410.2160 (2007-05-26 15:32:10) >> I measured the performance by running "ttcp" between my Laptop and my >> router. Using b43 on my Laptop gives about 2MB/s reported, and using >> ndiswrapper gives me about 3MB/s under exactly the same situations. >> Any ideas about what's going on? (I would be happy to provide you with >> any further specs on my computer). > > Yes. Broadcom wrote the Windows drivers, but never gave the > specifications to anyone else. Obvious those specs from their > engineers are better than those from the _reverse_ engineers for your > card. On my BCM4311/2 I get better throughput with the b43 driver than > I get when running Windows. I _NEVER_ use ndiswrapper. Now that b43 > works, why would I want to taint my kernel? I just moved to a different network and compared the performance between b43 and ndiswrapper. They are now *almost* identical (both 2.5MB/s). I'd even say that b43 sometimes performs slightly (50KB/s) better on average! (GO LINUX WIRELESS!) Looking at my syslog shows that on my home network (where b43 performed 50% worse), I find the following messages just after association: wlan0: switched to short barker preamble (BSSID=3D00:14:a5:0c:17:dc) wlan0: WMM queue=3D2 aci=3D0 acm=3D0 aifs=3D3 cWmin=3D15 cWmax=3D1023 b= urst=3D0 wlan0: WMM queue=3D3 aci=3D1 acm=3D0 aifs=3D7 cWmin=3D15 cWmax=3D1023 b= urst=3D0 wlan0: WMM queue=3D1 aci=3D2 acm=3D0 aifs=3D2 cWmin=3D7 cWmax=3D15 burs= t=3D30 wlan0: WMM queue=3D0 aci=3D3 acm=3D0 aifs=3D2 cWmin=3D3 cWmax=3D7 burst= =3D15 I don't find these messages when I connect on campus (and get the high performance). So maybe the performance loss is WMM related. My home router is of course running Linux (OpenWRT), so maybe I can tweak the WMM parameters of the router to match what b43 is happy with! Any suggestions, Thanks again for your help! GI --=20 'Pessimist' -- Optimist with experience. --YiEDa0DAkWCtVeE4 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (GNU/Linux) iEYEARECAAYFAkgYs9UACgkQ6plSLtsExHFL+wCfRPvT/SHWmujMEOnuMisw+eL1 BgYAn2QGtEvWoMPxw4ugW2PezuJ3HTRJ =RRB1 -----END PGP SIGNATURE----- --YiEDa0DAkWCtVeE4--