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SubjectRe: rt61pci - bad performance
Helmut Schaa wrote:
> Added rt2x00 mailinglist to CC ...
>
> Am Saturday 14 August 2010 schrieb Andreas:
>> Helmut Schaa wrote:
>>> Hi Andreas,
>>>
>>> Am Freitag 13 August 2010 schrieb Andrew Morton:
>>>> (cc's added)
>>>>
>>>> On Sun, 08 Aug 2010 11:49:49 +0200
>>>> Andreas<andihartmann@01019freenet.de> wrote:
>>>
>>> [...]
>>>
>>>>> 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.
>>>
>>> This doesn't look like an appropriate way to measure the throughput. You
>>> should use something like iperf [1] or netperf [2] for your measurements
>>> to get more accurate results.
>>>
>>>>> 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%).
>>>
>>> I wouldn't trust the link quality values that much, the calculation in rt61pi
>>> is most likely different from what the windows driver does. So it is not
>>> really comparable.
>>
>> I detected the problem using tunneled ssh-x-sessions and during copying
>> of data. I'm not really interested in the link-quality - I just need a
>> high performance :-).
>>
>>>>> 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.
>>>
>>> Could you elaborate please? Did you actually try to patch it or is this just
>>> an assumption?
>>
>> see my other mail!
>>
>>>>> Ndiswrapper shows an encryption key, rt61pci not. Does it mean, that
>>>>> rt61pci doesn't use hardware encryption?
>>>
>>> hw crypto should be enabled by default in rt61pci, however, I don't know
>>> if it is actually working ;)
>>
>> How can I see if it's working?
>
> You can add a printk to rt61pci_fill_rxdone, something like:
>
> diff --git a/drivers/net/wireless/rt2x00/rt61pci.c b/drivers/net/wireless/rt2x00/rt61pci.c
> index e539c6c..aa1aafd 100644
> --- a/drivers/net/wireless/rt2x00/rt61pci.c
> +++ b/drivers/net/wireless/rt2x00/rt61pci.c
> @@ -2023,6 +2023,7 @@ static void rt61pci_fill_rxdone(struct queue_entry *entry,
> rxdesc->flags |= RX_FLAG_DECRYPTED;
> else if (rxdesc->cipher_status == RX_CRYPTO_FAIL_MIC)
> rxdesc->flags |= RX_FLAG_MMIC_ERROR;
> + printk(KERN_INFO "rt61pci_fill_rxdone: %x\n", rxdesc->cipher_status);
> }
>
> /*
>
>
>>>>> 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?
>>>
>>> Please run proper measurements first and post the results again.
>>
>> I did some measurements with netperf (TCP_STREAM):
>>
>>
>> ndiswrapper
>> ===========
>>
>> (OpenSuSE 11.2 2.6.31.13-21):
>> download
>> average min max
>> 20,88 19,02 22,19 MBit/s (6 runs)
>>
>> upstream
>> average min max
>> 21,46 18,84 22,26 MBits/s (7 runs)
>>
>>
>> OpenSuSE 11.3 (2.6.34-12-desktop)
>> download
>> average min max
>> 21,41 20,51 22,51 MBit/s (16 runs)
>>
>>
>> upstream
>> average min max
>> error
>>
>>
>> rt61pci (patched - compat-wireless-2010-07-20)
>> ==============================================
>>
>> OpenSuSE 11.3 (2.6.34-12-desktop)
>> download
>> average min max
>> 15,54 12,4 17,19 MBit/s (25 runs)
>>
>> upstream
>> average min max
>> 13,54 12,1 14,04 MBits/s (7 runs)
>
> Hmm, ok that's quite a difference. Could you please mount debugfs
> (mount -t debugfs none /mnt), rerun the test and attach the contents
> of /mnt/ieee80211/phy0/stations/XX\:XX\:XX\:XX\:XX\:XX/rc_stats
> afterwards (XX:XX:XX:XX:XX:XX is the BSSID your connected to).

Wel, I did some tests. I tried to get same conditions (what is not as
easy). I will show here some results, which seem to be typical to me.


downstream
==========

netperf -t TCP_SENDFILE -H client
TCP SENDFILE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to client port 0
AF_INET
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. 10^6bits/sec

87380 16384 16384 10.36 16.38


/sys/kernel/debug/ieee80211/phy0/stations/xx:xx:xx:xx:xx:xx # cat rc_stats
rate throughput ewma prob this prob this succ/attempt success
attempts
1 0.7 76.2 100.0 0( 0) 11
11
2 0.0 0.0 0.0 0( 0) 0
0
5.5 0.0 0.0 0.0 0( 0) 0
0
11 0.0 0.0 0.0 0( 0) 0
2
6 0.0 0.0 0.0 0( 0) 0
32
9 0.0 0.0 0.0 0( 0) 551
1574
12 0.0 0.0 0.0 0( 0) 2096
6862
18 11.3 69.9 66.6 0( 0) 18047
25158
t 24 13.4 62.9 100.0 0( 0) 29100
42883
T P 36 28.2 92.8 100.0 1( 1) 135030 175797
48 4.4 11.3 0.0 0( 0) 361
3646
54 0.8 1.8 0.0 0( 0) 55
1727

Total packet count:: ideal 8917 lookaround 991



netperf -t TCP_STREAM -H client
TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to client port 0
AF_INET
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. 10^6bits/sec

87380 16384 16384 10.39 16.57


/sys/kernel/debug/ieee80211/phy0/stations/xx:xx:xx:xx:xx:xx # cat rc_stats
rate throughput ewma prob this prob this succ/attempt success
attempts
1 0.7 76.2 100.0 0( 0) 11
11
2 0.0 0.0 0.0 0( 0) 0
0
5.5 0.0 0.0 0.0 0( 0) 0
0
11 0.0 0.0 0.0 0( 0) 0
2
6 0.0 0.0 0.0 0( 0) 0
32
9 0.0 0.0 0.0 0( 0) 551
1614
12 0.0 0.0 0.0 0( 0) 2096
7047
t 18 12.8 79.2 80.0 0( 0) 18647
25949
24 9.9 46.7 100.0 0( 0) 29439
44023
T P 36 29.0 95.6 100.0 1( 1) 141588 183495
48 5.2 13.3 50.0 0( 0) 380
3781
54 12.4 28.6 100.0 0( 0) 60
1797

Total packet count:: ideal 6867 lookaround 763




upstream:
========

netperf -t TCP_MAERTS -H client
TCP MAERTS TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET client port 0 AF_INET
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. 10^6bits/sec

87380 16384 16384 10.56 13.19


/sys/kernel/debug/ieee80211/phy0/stations/xx:xx:xx:xx:xx:xx # cat rc_stats
rate throughput ewma prob this prob this succ/attempt success
attempts
1 0.7 76.2 100.0 0( 0) 11
11
2 0.0 0.0 0.0 0( 0) 0
0
5.5 0.0 0.0 0.0 0( 0) 0
0
11 0.0 0.0 0.0 0( 0) 0
2
6 0.0 0.0 0.0 0( 0) 0
32
9 0.0 0.0 0.0 0( 0) 551
1723
12 6.8 61.8 100.0 0( 0) 2122
7635
P 18 16.0 98.6 100.0 0( 0) 21199
29108
t 24 16.6 78.2 100.0 0( 0) 44090
61942
T 36 29.1 95.7 100.0 1( 1) 183435 238929
48 0.0 0.0 0.0 0( 0) 446
4861
54 0.0 0.0 0.0 0( 0) 67
2340

Total packet count:: ideal 6696 lookaround 743



netperf -t TCP_MAERTS -H client
TCP MAERTS TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to client port 0
AF_INET
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. 10^6bits/sec

87380 16384 16384 10.39 13.38


/sys/kernel/debug/ieee80211/phy0/stations/xx:xx:xx:xx:xx:xx # cat rc_stats
rate throughput ewma prob this prob this succ/attempt success
attempts
1 0.7 76.2 100.0 0( 0) 11
11
2 0.0 0.0 0.0 0( 0) 0
0
5.5 0.0 0.0 0.0 0( 0) 0
0
11 0.0 0.0 0.0 0( 0) 0
2
6 0.0 0.0 0.0 0( 0) 0
32
9 0.0 0.0 0.0 0( 0) 551
1534
12 0.0 0.0 0.0 0( 0) 2096
6669
18 15.5 95.4 100.0 0( 0) 17433
24342
tP 24 20.9 98.3 100.0 0( 0) 28782
41742
T 36 28.9 95.2 100.0 1( 1) 128587 168213
48 0.0 0.0 0.0 0( 0) 341
3510
54 0.0 0.0 0.0 0( 0) 54
1658

Total packet count:: ideal 2073 lookaround 230


It's remarkably, that the upstream is 3 Mbit/s lower than the downstream.

Does this help you? Do you need some more data? Feel free to ask!


>
>> rt61pci (original (unpatched) from OpenSuSE 11.3)
>> ==============================================
>>
>> download
>> 0,7 MBit/s
>>
>> upstream
>> error (interrupted system call)
>>
>>
>> If you compare ndiswrapper with rt61pci patched, there is a difference
>> of about 6 MBits/s. The unpatched version can't be used at all.
>
> Ok, so either the txpower handling in rt61pci needs to be reviewed or your
> eeprom contents are crippled up. Not sure though ...

Is there a way to check this? Can I do anything to test?


Kind regards,
Andreas


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