From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andreas Hofmann Date: Thu, 21 Oct 2010 18:24:52 +0200 Subject: [ath9k-devel] ath9k HT40 performance issues Message-ID: <4CC06954.4000304@corscience.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ath9k-devel@lists.ath9k.org 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. 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