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Date: Sat, 14 Aug 2010 10:33:34 +0200
From: Andreas <andihartmann@...19freenet.de>
To: linux-kernel@...r.kernel.org
Cc: Andrew Morton <akpm@...ux-foundation.org>,
Helmut Schaa <helmut.schaa@...glemail.com>
Subject: Re: rt61pci - bad performance
Andrew Morton wrote:
> (cc's added)
>
> On Sun, 08 Aug 2010 11:49:49 +0200
> Andreas<andihartmann@...19freenet.de> 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-
>> <TAbort-<MAbort->SERR-<PERR- INTx-
>> 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.
That's wrong. I detected, that there is a great difference, because if
you start the unpatched driver directly after the boot, the link isn't
useable at all.
I can't see any difference if the patched driver is loaded once and
removed and the unpatched is loaded afterwards without rebooting between.
The patch is:
--- rt61pci.c.orig 2010-07-20 21:03:02.000000000 +0200
+++ rt61pci.c 2010-08-14 10:27:52.708008193 +0200
@@ -2661,13 +2661,17 @@
spec->channels_info = info;
tx_power = rt2x00_eeprom_addr(rt2x00dev, EEPROM_TXPOWER_G_START);
- for (i = 0; i < 14; i++)
- info[i].tx_power1 = TXPOWER_FROM_DEV(tx_power[i]);
+ for (i = 0; i < 14; i++) {
+ // info[i].tx_power1 = TXPOWER_FROM_DEV(tx_power[i]);
+ info[i].tx_power1 = 25;
+ }
if (spec->num_channels > 14) {
tx_power = rt2x00_eeprom_addr(rt2x00dev,
EEPROM_TXPOWER_A_START);
- for (i = 14; i < spec->num_channels; i++)
- info[i].tx_power1 = TXPOWER_FROM_DEV(tx_power[i]);
+ for (i = 14; i < spec->num_channels; i++) {
+ // info[i].tx_power1 =
TXPOWER_FROM_DEV(tx_power[i]);
+ info[i].tx_power1 = 25;
+ }
}
return 0;
Kind regards,
Andreas
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