Posted: Wed Sep 16, 2009 13:25 Post subject: Netgear Wndr3300 CPU loading problems slow wireless
Alright here goes, I just bought a few wndr3300's and i have noticed that the cpu load average goes up to 3 when transferring data from a wired 100Mbps computer to a wireless computer at 270Mbps.
The data size is about 2GB and is transferring from windows to windows by typing in the ip address into the address bar in my computer. This displays the contents of my "shared" computer on the network. Then i copy and paste.
Upon this happening the data transfer rate goes from 8.00MBps to 6 MBps. While this is happeing the load average in dd wrt goes from 0.20 to about 3.0 and the dd wrt gui becomes unresponsive.
Im running mini build 12533 bone stock with no modifications other than setting the wireless wl0 to
NA only
Channel 100
40Mhz
upper
frame burst disabled
rock solid at 270Mbps
I did the 30/30/30 after flashing from the stock firmware.
If im transferring between two computers via wired then the cpu load never goes over 0.10 and the transfer rate is 11.5 - 12MBps. Its only when using the draft n side of the router.
The wireless G does not load the cpu at all only the wireless N.
I also tried eko's builds and brainslayer builds from 12387 to 12874 with the same results.
I guess what im trying to get at is, how do I get the cpu load down and the wireless transfer speed up. Since the wireless transfer speed is over twice the speed of the wired you would think that it could only be as fast as the slowest hardware in this case 11.5MBps.
Any help is appreciated, please let me know if im missing important information.
first off i've nailed why wireless network speeds are so slow.
If you telnet into your router, then type "top" to show the processes and cpu uses.
You'll notice that when doing the data transfer the process [ksoftirqd_CPU0] is using all of the processor when transfering.
Ive also noticed that "resetbutton" is for some reason using cpu usage too.
I've disabled reset button in dd-wrt and it seemed to increase the wireless speed a little bit.
However i also noticed that nas -P is drawing processor power too. I know that ksoftirqd_CPU0 is used for soft interrupts. and nas -P is used to bind the wireless with the wlan and lan on the router.
For whatever reason the soft irqs process is being overloaded buy too many interrupts.
If anyone finds anything out about this let me know.
Are you transferring a highly-compressed MPEG-2 or MPEG-4 media file? If so, it doesn't compress nearly so well as other wireless data and the effective throughput can appear lower. _________________ 2x Asus RT-AC68U
Posted: Wed Nov 11, 2009 6:27 Post subject: Re: Netgear Wndr3300 CPU loading problems slow wireless
btechnet wrote:
I guess what im trying to get at is, how do I get the cpu load down and the wireless transfer speed up. Since the wireless transfer speed is over twice the speed of the wired you would think that it could only be as fast as the slowest hardware in this case 11.5MBps.
Any help is appreciated, please let me know if im missing important information.
Yes, you'll probably to reset your real-world expectations for Wireless-N rated (theoretical) speeds.
A 300 Mbps Wireless-N rated connection (shown in Windows dialog) is just a theoretical number. It will likely result in a real-world throughput from 40Mbps to 95Mbps only (which can be less than a hardwired LAN 100Mbps connection) due to numerous extra variables, like channel interference, blocking objects, path loss, hardware manufacturer mis-matches, etc).
Read...
How to get the best possible Wireless-N speeds...
http://www.dd-wrt.com/phpBB2/viewtopic.php?t=60374 _________________ .
.
Get off my channel, or face the wrath of my 2.4Ghz Wireless-N channel-bonded 40Mhz wide-band interference!
My routers:
- 1 Linksys E3000
- 4 Linksys E2000
- 4 Linksys WRT320n [DD-WRT svn13575 std-nokaid] working well in WDS setup, 5Ghz N-speeds only.
- 2 Airlink AR670W [DD-WRT build 14537] working well in WDS setup, 2.4Ghz N-speeds only.
- 2 Netgear WDNR3300 [DD-WRT svn13577 std-nokaid] working well in AP-Repeater-Bridge setup, 5Ghz N-speeds only.
- Airlink AR325W G-router and Belkin F5D7230-4 v1444 [DD-WRT v23 sp2 micro] working well in Repeater-Bridge setup, G-speeds only.
- D-Link DI-614+ B-router, sitting around, wanna buy it?
Seeing the exact same issues here as well. Wired -> Wired file transfers seem fine, but when you do Wireless N -> Wired you get very high CPU usage on the router. Did anyone work out what was causing this issue? Running 13577M NEWD Eko on my WNDR3300, I killed off a few processes like httpd and resetbutton, and the transfer rate didn't improve, so don't think it's a bottleneck on CPU usage just curious why it's so high and if that's normal
Here's a copy of the top command
Code:
Load average: 0.69 0.45 0.18 3/26 28748
PID PPID USER STAT VSZ %MEM %CPU COMMAND
3 1 root RWN 0 0.0 58.9 [ksoftirqd_CPU0]
89 1 root S 1244 9.5 2.9 resetbutton
17 1 root S 1292 9.9 0.7 watchdog
5648 5622 root R 1184 9.0 0.4 top
181 1 root S 1176 9.0 0.2 telnetd
423 1 root S 2516 19.2 0.0 httpd -p 80
696 1 root S 1244 9.5 0.0 wland
606 1 root S 1224 9.3 0.0 upnp -D -W eth1
5622 181 root S 1196 9.1 0.0 -sh
250 1 root S 1172 8.9 0.0 ttraff
469 1 root S 1172 8.9 0.0 process_monitor
290 1 root S 1152 8.8 0.0 nas -P /tmp/nas.wl0lan.pid -H 34954 -l
300 1 root S 1152 8.8 0.0 nas -P /tmp/nas.wl1lan.pid -H 34954 -l
1 0 root S 912 6.9 0.0 /sbin/init noinitrd
512 1 root S 820 6.2 0.0 inadyn --input_file /tmp/ddns/inadyn.c
199 1 root S 808 6.1 0.0 dnsmasq --conf-file=/tmp/dnsmasq.conf
699 1 root S 700 5.3 0.0 udhcpc -i eth1 -p /var/run/udhcpc.pid
510 1 root S 696 5.3 0.0 cron
405 1 root S 688 5.2 0.0 udhcpd /tmp/udhcpd.conf
12 1 root SW 0 0.0 0.0 [mtdblockd]
I believe the problem is due to the wireless driver for k2.4 has to many soft irq requests. (a soft irq is a irq made on the "fly" within the kernel software.)
What i mean is the software controlling the driver uses irq interrupts to keep the "flow" of data smooth. Well that requires alot of cpu in order to keep things organized.
The way I solved the problem was installed 13575M NEWD-2 K2.6 Eko
Yes it's the wireless driver's soft interrupts using the CPU to copy data from its buffers.
http://www.dd-wrt.com/phpBB2/viewtopic.php?p=374691 _________________ Read the forum announcements thoroughly! Be cautious if you're inexperienced.
Available for paid consulting. (Don't PM about complicated setups otherwise)
Looking for bricks and spare routers to expand my collection. (not interested in G spec models)
I was using channel 116 with wpa2 and NA-Only. I only noticed about a 1-2 MBps increase in speed over k24. K26 is not alot but it is faster. Seems like i was getting around 10-12MBps which is about a solid 100Mbps wired speed.
The softirq cpu loading still happened (seems like it limits the actual wireless speed from working the cpu) but it wasn't nearly as bad as k24.
Eko 14205M seems to fix the bootup bug that existed before also. The bootup big is similar to the WRT610n v2 bootup bug. Where the router starts up but doesn't initalize the wireless or the webconsole. _________________ 1x WRT610Nv2 big - 14280 NEWD-2 K2.6 BrainSlayer
1x WNDR3300 mini - 14205M NEWD-2 K2.6 Eko
2x AR670w std - 14289 v24
Brainslayer
1x AR690w mini - 15649 v24
Brainslayer
2x AR430W std - 13064 v24 Brainslayer
2x WNR834B v2 mini - 14311 K2.4 BrainSlayer
1x RT-N16 big - 14280 NEWD-2 K2.6 BrainSlayer
1x WRT54G V5.0 micro - 15704 v24 Brainslayer
1x WRT54GL V1.1 micro - 15704 v24 Brainslayer