Return-path: Received: from smtp6-g19.free.fr ([212.27.42.36]:50070 "EHLO smtp6-g19.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751442AbYKXHeu (ORCPT ); Mon, 24 Nov 2008 02:34:50 -0500 Message-ID: <492A5913.3070007@free.fr> (sfid-20081124_083455_811898_5B9391D8) Date: Mon, 24 Nov 2008 08:34:43 +0100 From: Benoit PAPILLAULT MIME-Version: 1.0 To: Maxim Levitsky CC: Derek Smithies , ath5k-devel@lists.ath5k.org, linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org, ipw3945-devel@lists.sourceforge.net, wally@theblackmoor.net Subject: Re: [ath5k-devel] Unusually low speeds with ath5k and iwl3945 References: <492719ED.5000006@gmail.com> <20081122005240.GA27826@hash.localnet> <4927FC0C.10900@gmail.com> In-Reply-To: <4927FC0C.10900@gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-wireless-owner@vger.kernel.org List-ID: -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Maxim Levitsky a =E9crit : > Derek Smithies wrote: >> Hi, >> to verify that it is a rate control issue, there is one very simple= and=20 >> very practical test. >> >> Take both ends of your link, and set them to fixed rate, and at the = rate=20 >> you think it should be achieving. >> If you can achieve significantly higher throughputs with fixed rate,= you=20 >> know that the rate control algorithm (or interface with rate algorit= hm)=20 >> has failed. >> >> Derek. >> >> On Fri, 21 Nov 2008, Bob Copeland wrote: >> >>> On Fri, Nov 21, 2008 at 10:28:29PM +0200, Maxim Levitsky wrote: >>>> I initially blamed iwl3945, then thought it got fixed, but now I h= ave >>>> ath5k, and speeds are low >>>> and I suspect that both drivers has bugs regarding to speed. >>> Quite possible, but both use mac80211 for rate control. Which rate >>> control algorithm are you using? > Hi, >=20 > Well, iwl3945 was showing 54M all the time in iwconfig, > also it doesn't support setting fixed rate, at least not using iwconf= ig. >=20 > ath5k never shows higher that 18M, and supports setting fixed rate, b= ut if I set it to anything higher that 18M, > speeds drop to 0Kbytes/s immediately. > Speeds lower that 18M work, and affect throughput accordantly > For most of tests speeds are ether 18M or lower, but then when I set = them to 18M this didn't increase throughput. > =20 > iwl3945 was always at 54M >=20 >=20 >=20 > Best regards, > Maxim Levitsky I did a similar test here and results is very strange. AP was my good old linksys WRT54G running an iperf server. Client was a laptop running either ath5k or madwifi/trunk and an iperf client. Channel is 5. Both drivers show the same behaviour. At the beginning, throughput was very low : 500 - 600 kbit/s. Suddenly (after few minutes), it jumps to 15 - 17 Mbit/s and then few minutes later (let's say 10 - 20 minutes maybe), it jumps back to 500 - 600 kbit/s. Using a fixed rate has no effect. I used my latest wireless monitoring tools and I did not saw lost of duplicates or lost packets. The only difference was the number of packets sent by seconds.... Looking a my syslog, I just saw few messages, unrelated in time with th= e throughput going up or down. They were: - - ath5k : unsupported jumbo - - switching to short barker preamble - - switching to long barker preamble I can repeat the same test with iwl3945 as well, if needed. Regards, Beno=EEt -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFJKlkTOR6EySwP7oIRAnR1AJ0UCiENM0qtZwQYngkVpiLvrKtgLACfRKPz Wi/HreSX4NV+kfyeS+RMFaY=3D =3DRKcV -----END PGP SIGNATURE----- -- To unsubscribe from this list: send the line "unsubscribe linux-wireles= s" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html