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From: Stephen Donecker <sdonecker@ahmct.ucdavis.edu>
To: ath9k-devel@lists.ath9k.org
Subject: [ath9k-devel] Very large datagram loss
Date: Mon, 18 Jun 2012 21:07:45 -0700	[thread overview]
Message-ID: <4FDFFB11.4010901@ahmct.ucdavis.edu> (raw)
In-Reply-To: <CAJ-Vmok=FJDzpyyaGZ2znKorspbrzeeV0PUofLNm0xL7dEkLpA@mail.gmail.com>

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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  reply	other threads:[~2012-06-19  4:07 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
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 [this message]
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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