Netgear Wndr3300 CPU loading problems slow wireless

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btechnet
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Location: USA

PostPosted: Wed Sep 16, 2009 13:25    Post subject: Netgear Wndr3300 CPU loading problems slow wireless Reply with quote
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.
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LOM
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PostPosted: Wed Sep 16, 2009 15:56    Post subject: Reply with quote
You ain't got one of the fastest N-routers

http://www.smallnetbuilder.com/content/view/30502/96/

http://www.smallnetbuilder.com/component/option,com_chart/Itemid,189/

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btechnet
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PostPosted: Thu Sep 17, 2009 15:57    Post subject: Reply with quote
Well I went through and tested eko svn12774. It seemed to help slightly in the wireless transfer rate and the overall cpu load.

I also tested the netgear firmware 1.0.29na and that transfers at about 10MBps, compared to 6-8MBps with dd-wrt.

I also found that if you use an unsecured setup the transfer is faster.
btechnet
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PostPosted: Sat Oct 17, 2009 18:16    Post subject: Reply with quote
Well... I did some work on the wndr3300.

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.
KeithB
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Joined: 22 Jun 2008
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PostPosted: Sat Oct 17, 2009 18:52    Post subject: Reply with quote
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.
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btechnet
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Joined: 16 Sep 2009
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Location: USA

PostPosted: Sat Oct 17, 2009 19:02    Post subject: Reply with quote
no, the file is an umcompressed wav file.
bbb_forever
DD-WRT User


Joined: 10 Oct 2009
Posts: 202

PostPosted: Wed Nov 11, 2009 6:27    Post subject: Re: Netgear Wndr3300 CPU loading problems slow wireless Reply with quote
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

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.
.
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?

Recent fixes timeline:
http://svn.dd-wrt.com:8000/dd-wrt/timeline?from=01%2F11%2F2010&daysback=30&changeset=on&update=Update

Linksys 320n Path: Downloads › others › eko › V24-K26 › svn13575

Airlink AR670W Path: Downloads › others › eko › BrainSlayer-V24-preSP2 › 12-28-09-r13525 › airlink101-ar670w
PeteBest
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PostPosted: Fri Apr 30, 2010 8:35    Post subject: Reply with quote
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]
buddee
DD-WRT Guru


Joined: 06 Feb 2010
Posts: 7401
Location: Little Rock

PostPosted: Fri Apr 30, 2010 11:19    Post subject: Reply with quote
Another thing that helped me was turning off UPnP.
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btechnet
DD-WRT User


Joined: 16 Sep 2009
Posts: 181
Location: USA

PostPosted: Fri Apr 30, 2010 21:18    Post subject: Reply with quote
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

its a NEWD-2 with K2.6. the posting for it is here:
http://www.dd-wrt.com/phpBB2/viewtopic.php?t=63948

I found that with NEWD-2 K2.6 13575 the boot process is a bit clumsy. I found that 14205M Eko works the best. That can be found here:

http://www.dd-wrt.com/site/support/other-downloads?path=others%2Feko%2FV24-K26%2Fsvn14205%2F

_________________
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
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buddee
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Joined: 06 Feb 2010
Posts: 7401
Location: Little Rock

PostPosted: Fri Apr 30, 2010 21:29    Post subject: Reply with quote
thanx btechnet for the tip about the k2.6 on the wndr3300, i see that the wl1 is fixed now so i shall actually like to try this out.
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Naffer
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Joined: 21 May 2010
Posts: 2

PostPosted: Fri May 21, 2010 15:11    Post subject: Reply with quote
I've observed the same issue, but switching to NEWD-2 K2.6 14205 didn't seem to help. Did you make any other changes at the same time?
phuzi0n
DD-WRT Guru


Joined: 10 Oct 2006
Posts: 10143

PostPosted: Fri May 21, 2010 21:41    Post subject: Reply with quote
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

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btechnet
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Joined: 16 Sep 2009
Posts: 181
Location: USA

PostPosted: Sat May 22, 2010 2:09    Post subject: Reply with quote
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
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