From: Andreas Hofmann <andreas.hofmann@corscience.de>
To: ath9k-devel@lists.ath9k.org
Subject: [ath9k-devel] ath9k HT40 performance issues
Date: Thu, 21 Oct 2010 18:24:52 +0200 [thread overview]
Message-ID: <4CC06954.4000304@corscience.de> (raw)
Hello,
we are currently trying to set up a wireless connection using two
Atheros AR9280 wireless-cards. Used software is Linux 2.6.35.7 with the
corresponding ath9k-driver, hostapd and wpa_supplicant in stable
versions 7.2 and 7.3.
The problem is, while using the HT40 mode, the achieved data rates are
by far inferior than expected. When receiving, the wireless-cards seem
to be losing data due to CRC errors, also the rate adaption seems to act
overly aggressive in reducing the transfer speed due to packet errors.
Attached are the used configfiles, some logs and debugfs outputs to
clarify the problem.
When using HT20 mode, the speed-issues are not a problem - contrary to
the ~4,5/~12,5 MBit/s achieved at HT40, ~27 MBit/s are passing the link.
The problem persists between different platforms (mips64 and x86), using
current compat-wireless drivers (2010-10-17) did not fix the issue as well.
Is this a known problem and are there any existing fixes/workarounds?
Any help or hints would be greatly appreciated.
Kind regards,
Andreas Hofmann.
########
iwconfig
########
wlan0 IEEE 802.11abgn ESSID:"hapd"
Mode:Managed Frequency:5.18 GHz Access Point:
xx:xx:xx:xx:xx:xx
Bit Rate=6 Mb/s Tx-Power=30 dBm
Retry long limit:7 RTS thr:off Fragment thr:off
Power Management:off
Link Quality=65/70 Signal level=-45 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0
#############
hostapd.conf:
#############
ctrl_interface=/var/run/hostapd
interface=wlan0
driver=nl80211
ieee80211n=1
ht_capab=[HT40-]
auth_algs=1
wpa=2
wpa_key_mgmt=WPA-PSK
wpa_pairwise=CCMP
rsn_pairwise=CCMP
ssid=hapd
channel=40
hw_mode=a
wpa_passphrase=secretpassphrase
###################
wpa_supplicant.conf
###################
ctrl_interface=/var/run/wpa_supplicant
eapol_version=1
ap_scan=1
fast_reauth=1
network={
ssid="hapd"
scan_ssid=1
proto=RSN
key_mgmt=WPA-PSK
pairwise=CCMP
group=CCMP
psk="secretpassphrase"
}
###############
debugfs rcstat:
###############
HT MCS Rate Success Retries XRetries PER
6.0: 0 0 0 0
9.0: 0 0 0 0
12.0: 0 0 0 0
18.0: 0 0 0 0
24.0: 0 0 0 0
36.0: 0 0 0 0
48.0: 0 0 0 0
54.0: 0 0 0 0
HT20 0 6.5: 55100 8038 882 7
HT20 1 13.0: 0 0 0 0
HT20 2 19.5: 0 0 0 0
HT20 3 26.0: 0 0 0 0
HT20 4 39.0: 0 0 0 0
HT20 5 52.0: 0 0 0 0
HT20 6 58.5: 0 0 0 0
HT20 7 65.0: 0 0 0 0
HT20 8 13.0: 0 0 0 0
HT20 9 26.0: 0 0 0 0
HT20 10 39.0: 0 0 0 0
HT20 11 52.0: 0 0 0 0
HT20 12 78.0: 0 0 0 0
HT20 13 104.0: 0 0 0 0
HT20 14 117.0: 0 0 0 0
HT20 15 130.0: 0 0 0 0
HT40 0 13.5: 0 2468 4870 49
HT40 1 27.5: 0 44 22 68
HT40 2 40.5: 0 40 20 63
HT40 3 54.0: 2 16 2 60
HT40 4 81.5: 0 8 2 60
HT40 5 108.0: 0 0 0 0
HT40 6 121.5: 0 0 0 0
HT40 7 135.0: 0 0 0 0
HT40 7 150.0: 0 0 0 0
HT40 8 27.0: 0 0 0 0
HT40 9 54.0: 0 0 0 0
HT40 10 81.0: 0 0 0 0
HT40 11 108.0: 0 8 2 60
HT40 12 162.0: 0 8 2 60
HT40 13 216.0: 0 0 0 0
HT40 14 243.0: 0 0 0 0
HT40 15 270.0: 0 0 0 0
HT40 15 300.0: 0 0 0 0
#############
debugfs recv:
#############
CRC ERR : 396
DECRYPT CRC ERR : 0
PHY ERR : 0
MIC ERR : 0
PRE-DELIM CRC ERR : 0
POST-DELIM CRC ERR : 0
DECRYPT BUSY ERR : 0
UNDERRUN : 0
TIMING : 0
PARITY : 0
RATE : 0
LENGTH : 0
RADAR : 0
SERVICE : 0
TOR : 0
OFDM-TIMING : 0
OFDM-SIGNAL-PARITY : 0
OFDM-RATE : 0
OFDM-LENGTH : 0
OFDM-POWER-DROP : 0
OFDM-SERVICE : 0
OFDM-RESTART : 0
FALSE-RADAR-EXT : 0
CCK-TIMING : 0
CCK-HEADER-CRC : 0
CCK-RATE : 0
CCK-SERVICE : 0
CCK-RESTART : 0
CCK-LENGTH : 0
CCK-POWER-DROP : 0
HT-CRC : 0
HT-LENGTH : 0
HT-RATE : 0
###############
iperf logs (AP):
###############
# iperf -s
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[ 4] local 192.168.50.1 port 5001 connected with 192.168.50.2 port 54357
[ ID] Interval Transfer Bandwidth
[ 4] 0.0-98.2 sec 50.0 MBytes 4.27 Mbits/sec
# iperf -c 192.168.50.2 -n 50M
------------------------------------------------------------
Client connecting to 192.168.50.2, TCP port 5001
TCP window size: 16.0 KByte (default)
------------------------------------------------------------
[ 3] local 192.168.50.1 port 58165 connected with 192.168.50.2 port 5001
[ ID] Interval Transfer Bandwidth
[ 3] 0.0-33.3 sec 50.0 MBytes 12.6 Mbits/sec
#################
iperf logs (STA):
#################
# iperf -c 192.168.50.1 -n 50M
------------------------------------------------------------
Client connecting to 192.168.50.1, TCP port 5001
TCP window size: 16.0 KByte (default)
------------------------------------------------------------
[ 3] local 192.168.50.2 port 54357 connected with 192.168.50.1 port 5001
[ ID] Interval Transfer Bandwidth
[ 3] 0.0-97.7 sec 50.0 MBytes 4.29 Mbits/sec
# iperf -s
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[ 4] local 192.168.50.2 port 5001 connected with 192.168.50.1 port 58165
[ ID] Interval Transfer Bandwidth
[ 4] 0.0-33.4 sec 50.0 MBytes 12.6 Mbits/sec
--
Andreas Hofmann
Corscience GmbH& Co. KG
Henkestr. 91
D-91052 Erlangen
Germany
Tel: +49 9131 977986-442
Fax: +49 9131 977986-59
e-mail: andreas.hofmann at corscience.de
Internet: www.corscience.de
-------------------------------------------------
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next reply other threads:[~2010-10-21 16:24 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-21 16:24 Andreas Hofmann [this message]
2010-10-21 16:51 ` [ath9k-devel] ath9k HT40 performance issues Luis R. Rodriguez
2011-01-22 3:09 ` Ben Greear
-- strict thread matches above, loose matches on Subject: below --
2010-10-21 22:11 Lars Hardy
2010-10-22 8:44 ` Andreas Hofmann
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