* [ath9k-devel] Six weeks with ath9k - my impressions.
@ 2008-09-26 8:02 Mats Johannesson
0 siblings, 0 replies; only message in thread
From: Mats Johannesson @ 2008-09-26 8:02 UTC (permalink / raw)
To: ath9k-devel
Let me first extend a warm hug towards the whole bunch of developers,
or a respectful bow, whatever your cultural preferences are. I am
serious in my gratitude for this open driver. Thank you.
Now, to business. When ath9k hit kernel.org (2.6.27-rc2-git3) I dived
in with much anticipation, and emerged greatly satisfied. The driver
was on a par with madwifi-ng both when it came to stability and speed.
I never expected 11n speeds in such an early incarnation.
This bliss remained over -rc3, -rc4 and -rc5 <-- Best version to date!
Then things started to crumble. I don't know if changes in the mac80211
layer are involved, but something has gone seriously astray.
The driver is now so fragile that a simple 'nop' patch, intended to fix
an interrupt storm (-rc7-git4), incurs a regression in terms of
stability on my machine (from -rc7-git2). I can no longer make the
connection 'sticky' over a reboot (Wicd Manager), and other connectivity
anomalies have popped up.
Might I suggest that you look back to -rc5 and... ahem... revert the
last couple of weeks and start over? I jest only slightly.
Below are some iperf runs to illustrate the decline. While -rc5 was a
straight business, I had to rerun -rc7-x several times until the
numbers were relatively even within a 10 second chunk (not fluctuating
too much). So these are 'best of' sets.
iwconfig shows 'best of' numbers - equal for all - 1.3 and 4.7 metres:
Link Quality=107/100 Signal level:-26 dBm Noise level=-95 dBm
Link Quality=51/100 Signal level:-62 dBm Noise level=-95 dBm
This is a very quiet neighbourhood, max 5 APs during peak hours and
none close to my channel, and I conducted the runs early morning.
Summary: [~Mbits/sec]
_1.3 metres from AP (4.3 feet)_
27-rc5 ------> 35
27-rc7-git2 -> 33
27-rc7-git4 -> 17
_4.7 metres from AP (15.4 feet)_
27-rc5 ------> 25
27-rc7-git2 -> 21
27-rc7-git4 -> 24
Client machine is a Pentium II 400MHz with 387 meg memory.
Server machine is a AMD Athlon(tm) 64 Processor 3400+ with 2 gig memory.
AMD notebook -.- Wireless -.- AP --- 100Mbit ethernet --- Pentium
_PCCard D-Link DWA-652_
loke at sleipner:~$ lspci
[...]
02:00.0 Network controller: Atheros Communications, Inc. AR5416
802.11a/b/g/n Wireless PCI Adapter (rev 01)
_D-Link DIR-655 Access Point_
Security Mode: WPA-Personal
WPA Mode: WPA2 Only
Cipher Type: AES
802.11 Mode : 802.11n only
Wireless Channel : 2.412 GHz - CH 1
Transmission Rate: Best (automatic)
Channel Width: Auto 20/40 MHz
*** 2.6.27-rc5 ***
_1.3 metres from AP_
loke:loke:~$ iperf -c 192.168.1.34 -i1
------------------------------------------------------------
Client connecting to 192.168.1.34, TCP port 5001
TCP window size: 16.0 KByte (default)
------------------------------------------------------------
[ 3] local 192.168.1.33 port 44686 connected with 192.168.1.34 port 5001
[ ID] Interval Transfer Bandwidth
[ 3] 0.0- 1.0 sec 3.82 MBytes 32.0 Mbits/sec
[ 3] 1.0- 2.0 sec 4.38 MBytes 36.7 Mbits/sec
[ 3] 2.0- 3.0 sec 4.03 MBytes 33.8 Mbits/sec
[ 3] 3.0- 4.0 sec 4.73 MBytes 39.7 Mbits/sec
[ 3] 4.0- 5.0 sec 4.18 MBytes 35.1 Mbits/sec
[ 3] 5.0- 6.0 sec 4.27 MBytes 35.8 Mbits/sec
[ 3] 6.0- 7.0 sec 4.67 MBytes 39.2 Mbits/sec
[ 3] 7.0- 8.0 sec 4.40 MBytes 36.9 Mbits/sec
[ 3] 8.0- 9.0 sec 3.91 MBytes 32.8 Mbits/sec
[ 3] 0.0-10.0 sec 42.2 MBytes 35.4 Mbits/sec
_4.7 metres from AP_
loke:loke:~$ iperf -c 192.168.1.34 -i1
------------------------------------------------------------
Client connecting to 192.168.1.34, TCP port 5001
TCP window size: 16.0 KByte (default)
------------------------------------------------------------
[ 3] local 192.168.1.33 port 44685 connected with 192.168.1.34 port 5001
[ ID] Interval Transfer Bandwidth
[ 3] 0.0- 1.0 sec 2.91 MBytes 24.4 Mbits/sec
[ 3] 1.0- 2.0 sec 3.02 MBytes 25.4 Mbits/sec
[ 3] 2.0- 3.0 sec 2.93 MBytes 24.6 Mbits/sec
[ 3] 3.0- 4.0 sec 3.23 MBytes 27.1 Mbits/sec
[ 3] 4.0- 5.0 sec 2.69 MBytes 22.5 Mbits/sec
[ 3] 5.0- 6.0 sec 2.80 MBytes 23.5 Mbits/sec
[ 3] 6.0- 7.0 sec 2.55 MBytes 21.4 Mbits/sec
[ 3] 7.0- 8.0 sec 3.03 MBytes 25.4 Mbits/sec
[ 3] 8.0- 9.0 sec 3.19 MBytes 26.7 Mbits/sec
[ 3] 9.0-10.0 sec 3.11 MBytes 26.1 Mbits/sec
[ 3] 0.0-10.0 sec 29.4 MBytes 24.7 Mbits/sec
*** 2.6.27-rc7-git2 ***
_1.3 metres from AP_
loke:loke:~$ iperf -c 192.168.1.34 -i1
------------------------------------------------------------
Client connecting to 192.168.1.34, TCP port 5001
TCP window size: 16.0 KByte (default)
------------------------------------------------------------
[ 3] local 192.168.1.33 port 44714 connected with 192.168.1.34 port 5001
[ ID] Interval Transfer Bandwidth
[ 3] 0.0- 1.0 sec 4.23 MBytes 35.5 Mbits/sec
[ 3] 1.0- 2.0 sec 3.84 MBytes 32.2 Mbits/sec
[ 3] 2.0- 3.0 sec 4.06 MBytes 34.1 Mbits/sec
[ 3] 3.0- 4.0 sec 4.08 MBytes 34.2 Mbits/sec
[ 3] 4.0- 5.0 sec 3.89 MBytes 32.6 Mbits/sec
[ 3] 5.0- 6.0 sec 3.95 MBytes 33.1 Mbits/sec
[ 3] 6.0- 7.0 sec 3.78 MBytes 31.7 Mbits/sec
[ 3] 7.0- 8.0 sec 3.84 MBytes 32.2 Mbits/sec
[ 3] 8.0- 9.0 sec 3.64 MBytes 30.5 Mbits/sec
[ 3] 9.0-10.0 sec 3.88 MBytes 32.5 Mbits/sec
[ 3] 0.0-10.0 sec 39.2 MBytes 32.9 Mbits/sec
_4.7 metres from AP_
loke:loke:~$ iperf -c 192.168.1.34 -i1
------------------------------------------------------------
Client connecting to 192.168.1.34, TCP port 5001
TCP window size: 16.0 KByte (default)
------------------------------------------------------------
[ 3] local 192.168.1.33 port 44715 connected with 192.168.1.34 port 5001
[ ID] Interval Transfer Bandwidth
[ 3] 0.0- 1.0 sec 2.48 MBytes 20.8 Mbits/sec
[ 3] 1.0- 2.0 sec 2.58 MBytes 21.6 Mbits/sec
[ 3] 2.0- 3.0 sec 2.59 MBytes 21.8 Mbits/sec
[ 3] 3.0- 4.0 sec 2.50 MBytes 21.0 Mbits/sec
[ 3] 4.0- 5.0 sec 2.02 MBytes 17.0 Mbits/sec
[ 3] 5.0- 6.0 sec 2.66 MBytes 22.3 Mbits/sec
[ 3] 6.0- 7.0 sec 2.14 MBytes 18.0 Mbits/sec
[ 3] 7.0- 8.0 sec 2.67 MBytes 22.4 Mbits/sec
[ 3] 8.0- 9.0 sec 2.63 MBytes 22.1 Mbits/sec
[ 3] 9.0-10.0 sec 2.52 MBytes 21.1 Mbits/sec
[ 3] 0.0-10.0 sec 24.8 MBytes 20.8 Mbits/sec
*** 2.6.27-rc7-git4 ***
_1.3 metres from AP_
loke:loke:~$ iperf -c 192.168.1.34 -i1
------------------------------------------------------------
Client connecting to 192.168.1.34, TCP port 5001
TCP window size: 16.0 KByte (default)
------------------------------------------------------------
[ 3] local 192.168.1.33 port 44728 connected with 192.168.1.34 port 5001
[ ID] Interval Transfer Bandwidth
[ 3] 0.0- 1.0 sec 1000 KBytes 8.19 Mbits/sec
[ 3] 1.0- 2.0 sec 1.30 MBytes 10.9 Mbits/sec
[ 3] 2.0- 3.0 sec 400 KBytes 3.28 Mbits/sec
[ 3] 3.0- 4.0 sec 1.48 MBytes 12.4 Mbits/sec
[ 3] 4.0- 5.0 sec 2.98 MBytes 25.0 Mbits/sec
[ 3] 5.0- 6.0 sec 2.58 MBytes 21.6 Mbits/sec
[ 3] 6.0- 7.0 sec 1.55 MBytes 13.0 Mbits/sec
[ 3] 7.0- 8.0 sec 2.43 MBytes 20.4 Mbits/sec
[ 3] 8.0- 9.0 sec 3.18 MBytes 26.7 Mbits/sec
[ 3] 9.0-10.0 sec 2.95 MBytes 24.8 Mbits/sec
[ 3] 0.0-10.0 sec 19.8 MBytes 16.6 Mbits/sec
_4.7 metres from AP_
loke:loke:~$ iperf -c 192.168.1.34 -i1
------------------------------------------------------------
Client connecting to 192.168.1.34, TCP port 5001
TCP window size: 16.0 KByte (default)
------------------------------------------------------------
[ 3] local 192.168.1.33 port 44724 connected with 192.168.1.34 port 5001
[ ID] Interval Transfer Bandwidth
[ 3] 0.0- 1.0 sec 2.55 MBytes 21.4 Mbits/sec
[ 3] 1.0- 2.0 sec 2.45 MBytes 20.6 Mbits/sec
[ 3] 2.0- 3.0 sec 2.97 MBytes 24.9 Mbits/sec
[ 3] 3.0- 4.0 sec 2.77 MBytes 23.3 Mbits/sec
[ 3] 4.0- 5.0 sec 3.16 MBytes 26.5 Mbits/sec
[ 3] 5.0- 6.0 sec 2.96 MBytes 24.8 Mbits/sec
[ 3] 6.0- 7.0 sec 2.70 MBytes 22.7 Mbits/sec
[ 3] 7.0- 8.0 sec 2.92 MBytes 24.5 Mbits/sec
[ 3] 8.0- 9.0 sec 3.11 MBytes 26.1 Mbits/sec
[ 3] 9.0-10.0 sec 3.01 MBytes 25.2 Mbits/sec
[ 3] 0.0-10.0 sec 28.6 MBytes 24.0 Mbits/sec
Mvh
Mats Johannesson
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2008-09-26 8:02 [ath9k-devel] Six weeks with ath9k - my impressions Mats Johannesson
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