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gw
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Joined: 03 Dec 2006
Posts: 215
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 Posted: Sat Aug 02, 2008 1:32 am Post subject: SOLVED: iwl3945 performance |
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Setup:
card: Intel Corporation PRO/Wireless 3945ABG
drivers:- A) ipw3945-1.2.2 with kernel linux-2.6.26-gentoo
- B) iwl3945 with newest git wireless-testing kernel 2.6.27-rc1-wl
You get the latter (B) by:
| Code: | | git-clone git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-testing.git |
This gives you the complete kernel snapshot of the main linux wifi developper (John Linville).
Compile and install this wireless testing kernel; if you get an error while trying to rebuild the nvidia module, act according to this:
| Quote: | | http://www.nvnews.net/vbulletin/showthread.php?p=1730295 |
Given the grotesque way to apply the patch, it is kind of a hack; but it works.
Here are some relevant kernel configs:
| Code: | zcat /proc/config.gz| egrep -i "iwl|mac8|wirel"
CONFIG_WIRELESS=y
CONFIG_WIRELESS_EXT=y
CONFIG_WIRELESS_EXT_SYSFS=y
CONFIG_MAC80211=m
CONFIG_MAC80211_RC_PID=y
CONFIG_MAC80211_RC_DEFAULT_PID=y
CONFIG_MAC80211_RC_DEFAULT="pid"
CONFIG_MAC80211_MESH=y
CONFIG_MAC80211_LEDS=y
# CONFIG_MAC80211_DEBUG_MENU is not set
# Wireless LAN
# CONFIG_MAC80211_HWSIM is not set
CONFIG_IWLWIFI=m
CONFIG_IWLCORE=m
# CONFIG_IWLWIFI_LEDS is not set
CONFIG_IWLWIFI_RFKILL=y
# CONFIG_IWLWIFI_DEBUG is not set
# CONFIG_IWLAGN is not set
CONFIG_IWL3945=m
CONFIG_IWL3945_RFKILL=y
CONFIG_IWL3945_SPECTRUM_MEASUREMENT=y
CONFIG_IWL3945_LEDS=y
# CONFIG_IWL3945_DEBUG is not set
# CONFIG_IPWIRELESS is not set
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Testing:
I transfer data between two computers on the same LAN (and room), laptop and desktop, laptop has the wifi card: laptop <---wireless---> wlan router <---wired---> desktop.
I used two programs for checking the throughput of each driver
- net-analyzer/netperf-2.4.4
- simple scp
I give the client-server based netperf (netserver on the corresponding machine) a 100 seconds run. With scp I transferred a file sized 730787830 bytes.
Results:
A) Using the old deprecated driver ipw3945
Receiving data:
| Quote: | root@desktop:~> netperf -l 100 -H laptop
TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to laptop (192.168.1.2) port 0 AF_INET
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. 10^6bits/sec
87380 16384 16384 100.05 18.31 |
And:
| Quote: | time scp film.avi me@laptop:/tmp
Password:
film.avi 100% 697MB 1.8MB/s 06:23
scp film.avi me@laptop:/tmp 17,66s user 6,25s system 6% cpu 6:37,12 |
Sending data:
| Quote: | root@laptop:~> netperf -l 100 -H desktop
TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to desktop (192.168.1.1) port 0 AF_INET
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. 10^6bits/sec
87380 16384 16384 100.66 23.11 |
And:
| Quote: | time scp film.avi me@desktop:/tmp
Password:
film.avi 100% 697MB 2.7MB/s 04:18
scp film.avi me@desktop:/tmp 21,39s user 12,61s system 12% cpu 4:23,02 total |
Brandnew iwl3945 driver and 2.6.27 wireless-testing kernel:
Receiving data:
| Quote: | root@desktop:~> netperf -l 100 -H laptop
TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to laptop (192.168.1.2) port 0 AF_INET
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. 10^6bits/sec
87380 16384 16384 100.05 18.00 |
And:
| Quote: | time scp film.avi me@laptop:/tmp
Password:
film.avi 100% 697MB 2.1MB/s 05:40
scp film.avi me@laptop:/tmp 18,37s user 6,07s system 7% cpu 5:45,59 total |
Sending data:
| Quote: | root@laptop:~> netperf -l 100 -H desktop
TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to linux (192.168.14.1) port 0 AF_INET
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. 10^6bits/sec
87380 16384 16384 102.35 9.34 |
And:
| Quote: | time scp film.avi me@desktop:/tmp [1:28]
Password:
scp film.avi me@desktop:/tmp 15,24s user 12,20s system 4% cpu 10:23,71 total |
To sum it up:
When receiving data, both drivers give roughly the same (mediocre) performance, about 18Mbit/s, which is considerably below the 25Mbit/sec that should be possible.
When sending data the picture ist completely different:
- the old ipw3945 has a very good performance of 23Mbit/s
- the new iwl3945 completely breaks down and gives only 10Mbit/s
Could you provide comparable numbers, preferably with netperf.
And how come that performance differs so dramatically between sending/receiving data? How can I check if this is due to driver, wlan hardware or whatever?
Thanks
gw
Last edited by gw on Sun Apr 12, 2009 8:31 am; edited 2 times in total |
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gw
Apprentice
Joined: 03 Dec 2006
Posts: 215
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| Posted: Sun Apr 12, 2009 8:29 am Post subject: |
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Now after a very long time and several kernels on:
| Code: |
uname -a
Linux linux 2.6.29-gentoo #1 SMP |
the wlan performance problem nearly vanished, I almost get the transfer rates of the old ipw3945 driver, especially when sending data: from 2.6.26 on it came down to about 1MB/s but now -- with 2.6.29 and probably the new firmware! -- it is miraculously up again at ca 2.5MB/s! I didn't change anything on my router configuration so it has to be something with the driver/firmware/kernel.
gw |
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