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* [ath9k-devel] Very large datagram loss
@ 2012-06-14  2:37 Stephen Donecker
  2012-06-16 21:09 ` Adrian Chadd
  2012-06-16 21:28 ` Felix Fietkau
  0 siblings, 2 replies; 6+ messages in thread
From: Stephen Donecker @ 2012-06-14  2:37 UTC (permalink / raw)
  To: ath9k-devel

Hi,

I am experiencing very high datagram loss between two identical cards 
communicating over a single spacial stream in adhoc mode. Using 
minstrel_ht rate control the tx bitrate settles at MCS7 150Mbps, and I 
get the following iperf results.

# iperf -c 192.168.11.2 -p 7777 -u -b 150m -t 10 -i 1
------------------------------------------------------------
Client connecting to 192.168.11.2, UDP port 7777
Sending 1470 byte datagrams
UDP buffer size:  160 KByte (default)
------------------------------------------------------------
[  3] local 192.168.11.1 port 43287 connected with 192.168.11.2 port 7777
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0- 1.0 sec  16.1 MBytes   135 Mbits/sec
[  3]  1.0- 2.0 sec  16.3 MBytes   137 Mbits/sec
[  3]  2.0- 3.0 sec  16.3 MBytes   137 Mbits/sec
[  3]  3.0- 4.0 sec  15.9 MBytes   133 Mbits/sec
[  3]  4.0- 5.0 sec  16.4 MBytes   138 Mbits/sec
[  3]  5.0- 6.0 sec  16.0 MBytes   134 Mbits/sec
[  3]  6.0- 7.0 sec  16.2 MBytes   136 Mbits/sec
[  3]  7.0- 8.0 sec  16.0 MBytes   135 Mbits/sec
[  3]  8.0- 9.0 sec  16.2 MBytes   136 Mbits/sec
[  3]  0.0-10.0 sec   161 MBytes   135 Mbits/sec
[  3] Sent 115053 datagrams
[  3] Server Report:
[  3]  0.0-10.0 sec  92.0 MBytes  77.0 Mbits/sec   0.262 ms 49459/115052 
(43%)
[  3]  0.0-10.0 sec  1 datagrams received out-of-order

When I set minstrel_ht to fixed_rate MCS7 I get the following iperf results.

# iperf -c 192.168.11.2 -p 7777 -u -b 150m -t 10 -i 1
------------------------------------------------------------
Client connecting to 192.168.11.2, UDP port 7777
Sending 1470 byte datagrams
UDP buffer size:  160 KByte (default)
------------------------------------------------------------
[  3] local 192.168.11.1 port 55776 connected with 192.168.11.2 port 7777
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0- 1.0 sec  17.4 MBytes   146 Mbits/sec
[  3]  1.0- 2.0 sec  17.4 MBytes   146 Mbits/sec
[  3]  2.0- 3.0 sec  17.6 MBytes   147 Mbits/sec
[  3]  3.0- 4.0 sec  17.4 MBytes   146 Mbits/sec
[  3]  4.0- 5.0 sec  17.5 MBytes   147 Mbits/sec
[  3]  5.0- 6.0 sec  17.6 MBytes   148 Mbits/sec
[  3]  6.0- 7.0 sec  17.4 MBytes   146 Mbits/sec
[  3]  7.0- 8.0 sec  17.4 MBytes   146 Mbits/sec
[  3]  8.0- 9.0 sec  17.8 MBytes   149 Mbits/sec
[  3]  0.0-10.0 sec   175 MBytes   147 Mbits/sec
[  3] Sent 124930 datagrams
[  3] Server Report:
[  3]  0.0-10.2 sec  10.2 MBytes  8.39 Mbits/sec   4.527 ms 
117609/124920 (94%)
[  3]  0.0-10.2 sec  1 datagrams received out-of-order

In either case the overall throughput and datagram loss percentages are 
terrible. I believe overall the datagram loss should be less than a few 
percent.

Any ideas how I can determine where the packets are getting lost?

Thanks,

-Stephen

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* [ath9k-devel] Very large datagram loss
  2012-06-14  2:37 [ath9k-devel] Very large datagram loss Stephen Donecker
@ 2012-06-16 21:09 ` Adrian Chadd
  2012-06-19  4:07   ` Stephen Donecker
  2012-06-16 21:28 ` Felix Fietkau
  1 sibling, 1 reply; 6+ messages in thread
From: Adrian Chadd @ 2012-06-16 21:09 UTC (permalink / raw)
  To: ath9k-devel

Hi,

You should first report what hardware, which channel, what configuration, etc.

Next is likely looking at the TX and RX side of things.

TX - check short/long retries, what the minstrel_ht rate control
debugging says. It should give you throughput information per rate
that it tries. Look at short/long retry counts.
RX - look at CRC errors.



Adrian

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [ath9k-devel] Very large datagram loss
  2012-06-14  2:37 [ath9k-devel] Very large datagram loss Stephen Donecker
  2012-06-16 21:09 ` Adrian Chadd
@ 2012-06-16 21:28 ` Felix Fietkau
  2012-06-18 22:54   ` Stephen Donecker
  1 sibling, 1 reply; 6+ messages in thread
From: Felix Fietkau @ 2012-06-16 21:28 UTC (permalink / raw)
  To: ath9k-devel

On 2012-06-14 4:37 AM, Stephen Donecker wrote:
> Hi,
> 
> I am experiencing very high datagram loss between two identical cards
> communicating over a single spacial stream in adhoc mode. Using
> minstrel_ht rate control the tx bitrate settles at MCS7 150Mbps, and I
> get the following iperf results.
> 
> # iperf -c 192.168.11.2 -p 7777 -u -b 150m -t 10 -i 1
> ------------------------------------------------------------
> Client connecting to 192.168.11.2, UDP port 7777
> Sending 1470 byte datagrams
> UDP buffer size:  160 KByte (default)
> ------------------------------------------------------------
> [  3] local 192.168.11.1 port 43287 connected with 192.168.11.2 port 7777
> [ ID] Interval       Transfer     Bandwidth
> [  3]  0.0- 1.0 sec  16.1 MBytes   135 Mbits/sec
> [  3]  1.0- 2.0 sec  16.3 MBytes   137 Mbits/sec
> [  3]  2.0- 3.0 sec  16.3 MBytes   137 Mbits/sec
> [  3]  3.0- 4.0 sec  15.9 MBytes   133 Mbits/sec
> [  3]  4.0- 5.0 sec  16.4 MBytes   138 Mbits/sec
> [  3]  5.0- 6.0 sec  16.0 MBytes   134 Mbits/sec
> [  3]  6.0- 7.0 sec  16.2 MBytes   136 Mbits/sec
> [  3]  7.0- 8.0 sec  16.0 MBytes   135 Mbits/sec
> [  3]  8.0- 9.0 sec  16.2 MBytes   136 Mbits/sec
> [  3]  0.0-10.0 sec   161 MBytes   135 Mbits/sec
> [  3] Sent 115053 datagrams
> [  3] Server Report:
> [  3]  0.0-10.0 sec  92.0 MBytes  77.0 Mbits/sec   0.262 ms 49459/115052
> (43%)
> [  3]  0.0-10.0 sec  1 datagrams received out-of-order
> 
> When I set minstrel_ht to fixed_rate MCS7 I get the following iperf results.
> 
> # iperf -c 192.168.11.2 -p 7777 -u -b 150m -t 10 -i 1
> ------------------------------------------------------------
> Client connecting to 192.168.11.2, UDP port 7777
> Sending 1470 byte datagrams
> UDP buffer size:  160 KByte (default)
> ------------------------------------------------------------
> [  3] local 192.168.11.1 port 55776 connected with 192.168.11.2 port 7777
> [ ID] Interval       Transfer     Bandwidth
> [  3]  0.0- 1.0 sec  17.4 MBytes   146 Mbits/sec
> [  3]  1.0- 2.0 sec  17.4 MBytes   146 Mbits/sec
> [  3]  2.0- 3.0 sec  17.6 MBytes   147 Mbits/sec
> [  3]  3.0- 4.0 sec  17.4 MBytes   146 Mbits/sec
> [  3]  4.0- 5.0 sec  17.5 MBytes   147 Mbits/sec
> [  3]  5.0- 6.0 sec  17.6 MBytes   148 Mbits/sec
> [  3]  6.0- 7.0 sec  17.4 MBytes   146 Mbits/sec
> [  3]  7.0- 8.0 sec  17.4 MBytes   146 Mbits/sec
> [  3]  8.0- 9.0 sec  17.8 MBytes   149 Mbits/sec
> [  3]  0.0-10.0 sec   175 MBytes   147 Mbits/sec
> [  3] Sent 124930 datagrams
> [  3] Server Report:
> [  3]  0.0-10.2 sec  10.2 MBytes  8.39 Mbits/sec   4.527 ms
> 117609/124920 (94%)
> [  3]  0.0-10.2 sec  1 datagrams received out-of-order
> 
> In either case the overall throughput and datagram loss percentages are
> terrible. I believe overall the datagram loss should be less than a few
> percent.
Your expectations seem quite wrong. A PHY rate of 150 Mbit/s will not
get you anywhere near 150 Mbit/s UDP throughput, there's lots of 802.11
related overhead inbetween.
To check some stats on tx rate and retransmissions, take a look at
/sys/kernel/debug/ieee80211/phy0/netdev:wlan0/stations/*/rc_stats
(without fixed-rate).
One reason why the fixed-rate iperf looks so much worse is that it
disables aggregation.

- Felix

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [ath9k-devel] Very large datagram loss
  2012-06-16 21:28 ` Felix Fietkau
@ 2012-06-18 22:54   ` Stephen Donecker
  0 siblings, 0 replies; 6+ messages in thread
From: Stephen Donecker @ 2012-06-18 22:54 UTC (permalink / raw)
  To: ath9k-devel

Felix,

Thanks for you reply.
> Your expectations seem quite wrong. A PHY rate of 150 Mbit/s will not
> get you anywhere near 150 Mbit/s UDP throughput, there's lots of 802.11
> related overhead inbetween.
My tests above show that I was only getting 77.0 Mbps UDP on a PHY of 
150Mbps. I don't think it is unreasonable to expect better performance 
than this.

My setup:
Routerstations (AR7161 @680MHz)
SR71-15 (AR9220/AR9280 802.11an)
Openwrt r32347

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [ath9k-devel] Very large datagram loss
  2012-06-16 21:09 ` Adrian Chadd
@ 2012-06-19  4:07   ` Stephen Donecker
  2012-08-06 16:15     ` abhinav narain
  0 siblings, 1 reply; 6+ messages in thread
From: Stephen Donecker @ 2012-06-19  4:07 UTC (permalink / raw)
  To: ath9k-devel

Adrian,

Thanks for your reply.
> You should first report what hardware, which channel, what configuration, etc.

Ubiquity Routerstation (Atheros AR7161 @ 680MHz)
Ubiquity SR71-15 (Atheros AR9220/AR9280) 802.11n 2T2R
OpenWRT r32347

mode adhoc
channel 157
frequency 5785MHz
channel type HT40+
rate control minstrel_ht
dual stream MCS15 300Mbps

> Next is likely looking at the TX and RX side of things.
I have been doing some extensive testing and discovered that a lot of 
packets are being dropped on the tx side with few if any drops on the rx 
side. With a PHY of 300Mbps I get about 100Mbps UDP.
> TX - check short/long retries, what the minstrel_ht rate control
> debugging says. It should give you throughput information per rate
> that it tries. Look at short/long retry counts.
> RX - look at CRC errors.
>
long_retry_limit 4
short_retry_limit 7

type      rate     throughput  ewma prob   this prob  this 
succ/attempt   success    attempts
HT20/LGI    MCS0        6.6       99.9      100.0          0(  0)        
989         990
HT20/LGI    MCS1       13.0       99.9      100.0          0(  0)        
989         991
HT20/LGI    MCS2       19.1       99.9      100.0          0(  0)       
1026        1027
HT20/LGI    MCS3       25.0       99.9      100.0          0(  0)       
1060        1065
HT20/LGI    MCS4       36.2       99.6      100.0          0(  0)       
1036        1040
HT20/LGI    MCS5       46.5       99.9      100.0          0(  0)        
959         962
HT20/LGI    MCS6       51.2       99.9      100.0          0(  0)        
969         973
HT20/LGI    MCS7       56.9       99.7      100.0          0(  0)        
971         977
HT20/LGI    MCS8       13.0       99.9      100.0          0(  0)        
969         974
HT20/LGI    MCS9       25.0       99.9      100.0          0(  0)        
974         977
HT20/LGI    MCS10      36.3       99.9      100.0          0(  0)       
1007        1014
HT20/LGI    MCS11      46.5       99.9      100.0          0(  0)       
1017        1020
HT20/LGI    MCS12      66.2       99.9      100.0          0(  0)       
1058        1062
HT20/LGI    MCS13      81.2       99.9      100.0          0(  0)        
973         977
HT20/LGI    MCS14      90.0       99.9      100.0          0(  0)        
966         968
HT20/LGI    MCS15      86.8       89.4      100.0          0(  0)        
969         976
HT40/LGI    MCS0       13.5       99.9      100.0          0(  0)        
983         986
HT40/LGI    MCS1       26.0       99.9      100.0          0(  0)        
996        1000
HT40/LGI    MCS2       37.4       99.9      100.0          0(  0)       
1014        1018
HT40/LGI    MCS3       48.2       99.9      100.0          0(  0)       
1026        1033
HT40/LGI    MCS4       68.0       99.9      100.0          0(  0)       
1059        1062
HT40/LGI    MCS5       84.0      100.0      100.0          0(  0)        
975         975
HT40/LGI    MCS6       93.4       99.9      100.0          0(  0)        
970         974
HT40/LGI    MCS7      101.0       99.9      100.0          0(  0)        
976         978
HT40/LGI    MCS8       25.4       97.4      100.0          0(  0)        
963         971
HT40/LGI    MCS9       48.2       99.9      100.0          0(  0)        
975         982
HT40/LGI    MCS10      68.0       99.9      100.0          0(  0)        
978         985
HT40/LGI    MCS11      84.0      100.0      100.0          0(  0)       
1014        1014
HT40/LGI    MCS12     114.9       99.9      100.0          0(  0)       
1049        1051
HT40/LGI    MCS13     133.3       99.9      100.0          0(  0)        
970         972
HT40/LGI    MCS14     148.0       99.2      100.0          0(  0)        
983         987
HT40/LGI  t MCS15     158.7       99.9      100.0          0(  0)       
8419        8533
HT40/SGI    MCS0       14.9       99.9      100.0          0(  0)        
973         977
HT40/SGI    MCS1       28.7       99.9      100.0          0(  0)        
993         995
HT40/SGI    MCS2       41.1       99.9      100.0          0(  0)       
1003        1008
HT40/SGI    MCS3       52.9       99.9      100.0          0(  0)       
1013        1018
HT40/SGI    MCS4       74.0       99.9      100.0          1(  1)       
1027        1032
HT40/SGI    MCS5       90.9      100.0      100.0          0(  0)        
978         978
HT40/SGI    MCS6      101.0       99.9      100.0          0(  0)        
973         974
HT40/SGI   PMCS7      108.6       99.9      100.0          0(  0)        
974         976
HT40/SGI    MCS8       28.7       99.9      100.0          0(  0)        
978         983
HT40/SGI    MCS9       52.9       99.9      100.0          0(  0)        
978         984
HT40/SGI    MCS10      74.0       99.9      100.0          0(  0)        
994         998
HT40/SGI    MCS11      90.8       99.9      100.0          0(  0)       
1017        1019
HT40/SGI    MCS12     123.4       99.9      100.0          0(  0)       
1056        1066
HT40/SGI    MCS13     140.3       99.6      100.0          0(  0)        
991         999
HT40/SGI    MCS14     158.7       99.9      100.0          0(  0)      
18269       18402
HT40/SGI T  MCS15     165.2       99.1       98.7        553(560)   
10865638    11039921

Total packet count::    ideal 10890621      lookaround 46906
Average A-MPDU length: 4.8

I am not sure where I am to find the short and long retry counts.



In conclusion I discovered that during Tx the CPU load is almost 100%.



Thanks again,

-Stephen

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* [ath9k-devel] Very large datagram loss
  2012-06-19  4:07   ` Stephen Donecker
@ 2012-08-06 16:15     ` abhinav narain
  0 siblings, 0 replies; 6+ messages in thread
From: abhinav narain @ 2012-08-06 16:15 UTC (permalink / raw)
  To: ath9k-devel

Can some please tell what does this throughput represent  ?
at PHY layer ?

> type      rate     throughput  ewma prob   this prob  this succ/attempt
> success    attempts
> HT20/LGI    MCS0        6.6       99.9      100.0          0(  0)
> 989         990
> HT20/LGI    MCS1       13.0       99.9      100.0          0(  0)
> 989         991
>

thanks,
abhinav

>
>
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end of thread, other threads:[~2012-08-06 16:15 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2012-06-14  2:37 [ath9k-devel] Very large datagram loss Stephen Donecker
2012-06-16 21:09 ` Adrian Chadd
2012-06-19  4:07   ` Stephen Donecker
2012-08-06 16:15     ` abhinav narain
2012-06-16 21:28 ` Felix Fietkau
2012-06-18 22:54   ` Stephen Donecker

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