Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761142Ab0HLXMI (ORCPT ); Thu, 12 Aug 2010 19:12:08 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:36204 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761087Ab0HLXMF (ORCPT ); Thu, 12 Aug 2010 19:12:05 -0400 Date: Thu, 12 Aug 2010 16:11:57 -0700 From: Andrew Morton To: Andreas Cc: linux-kernel@vger.kernel.org, Ivo van Doorn , Gertjan van Wingerde , linux-wireless@vger.kernel.org Subject: Re: rt61pci - bad performance Message-Id: <20100812161157.00d5377f.akpm@linux-foundation.org> In-Reply-To: References: X-Mailer: Sylpheed 2.4.8 (GTK+ 2.12.9; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4822 Lines: 113 (cc's added) On Sun, 08 Aug 2010 11:49:49 +0200 Andreas wrote: > Hello! > > I've got the following hardware > > > 01:05.0 Network controller: RaLink RT2561/RT61 rev B 802.11g > Subsystem: Micro-Star International Co., Ltd. Device b833 > Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV+ VGASnoop- > ParErr- Stepping- SERR- FastB2B- DisINTx- > Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=slow >TAbort- > SERR- Latency: 128, Cache Line Size: 64 bytes > Interrupt: pin A routed to IRQ 21 > Region 0: Memory at cc000000 (32-bit, non-prefetchable) [size=32K] > Capabilities: [40] Power Management version 2 > Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA > PME(D0-,D1-,D2-,D3hot-,D3cold-) > Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME- > Kernel driver in use: ndiswrapper > > > running on a 32bit notebook with kernel 2.6.34-12-desktop (OpenSuSE > 11.3). There is no difference between the compat-wireless-modules > 2010-07-20 and the original modules shipped with the openSuSE 11.3 kernel. > > If the rt61-chip is connected to a AP using rt61pci, the best > throughput, which can be achieved (at the same place), is about 1,7 > MBytes/s. > > kernel: [ 656.112190] cfg80211: Calling CRDA to update world regulatory > domain > kernel: [ 656.112267] cfg80211: Calling CRDA for country: DE > kernel: [ 656.169518] cfg80211: Regulatory domain changed to country: DE > kernel: [ 656.169524] (start_freq - end_freq @ bandwidth), > (max_antenna_gain, max_eirp) > kernel: [ 656.169528] (2400000 KHz - 2483500 KHz @ 40000 KHz), > (N/A, 2000 mBm) > kernel: [ 656.169532] (5150000 KHz - 5350000 KHz @ 40000 KHz), > (N/A, 2000 mBm) > kernel: [ 656.169535] (5470000 KHz - 5725000 KHz @ 40000 KHz), > (N/A, 2698 mBm) > kernel: [ 656.206228] rt61pci 0000:01:05.0: PCI INT A -> GSI 21 (level, > low) -> IRQ 21 > kernel: [ 656.219941] phy0: Selected rate control algorithm 'minstrel' > kernel: [ 656.222216] Registered led device: rt61pci-phy0::radio > kernel: [ 656.222658] Registered led device: rt61pci-phy0::assoc > kernel: notebook1 ifup: wlan0 device: RaLink RT2561/RT61 rev B > 802.11g > > > > wlan0 IEEE 802.11bg ESSID:"--------" > Mode:Managed Frequency:2.412 GHz Access Point: some AP > Bit Rate=1 Mb/s Tx-Power=5 dBm > Retry long limit:7 RTS thr:off Fragment thr:off > Encryption key:off > Power Management:off > Link Quality=38/70 Signal level=-72 dBm > Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 > Tx excessive retries:0 Invalid misc:0 Missed beacon:0 > > The throughput is measured with ping -f -s 7000 and xosview -n. > > > > > If I'm using ndiswrapper with the windows driver, first of all, I can > see additional information in iwconfig: > > wlan0 IEEE 802.11g ESSID:"--------" > Mode:Managed Frequency:2.412 GHz Access Point: some AP > Bit Rate=54 Mb/s Tx-Power:20 dBm Sensitivity=-121 dBm > RTS thr=2347 B Fragment thr=2346 B > Encryption key:some key Security mode:restricted > Power Management:off > Link Quality:62/100 Signal level:-56 dBm Noise level:-96 dBm > Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 > Tx excessive retries:0 Invalid misc:0 Missed beacon:0 > > > There is a switch for sensitivity (which is not supported with rt61pci) > and the link quality compared with ndiswrapper is worse (38% to 62%). > > The following is remarkably too: > ndiswrapper uses a Tx-Power of 20 dBm, rt61pci only 5 dBm. I don't know, > why rt61pci uses 5 dBm. It's a hard limit and I can't set it on a value > higher than 5 unless the driver is patched. Nevertheless, setting a > higher value (of 20 dBm) by patch does not mean to get a better performance. > Ndiswrapper shows an encryption key, rt61pci not. Does it mean, that > rt61pci doesn't use hardware encryption? > > > With ndiswrapper, the rt61pci-chip achieves a throughput of 2,6 MBytes/s > - that's about 1 MByte/s more than rt61pci. > > I have to say, that the difference between rt61pci and ndiswrapper gets > worse if the link quality is getting more badly. Or in other words: > ndiswrapper handles bad connections better then rt61pci. > > > Do you have any idea to get rt61pci working as fast as ndiswrapper? > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/