Asus RT AC87U high CPU load downloading torrents

[Chrismallia]

Hi does anyone have a Idea why when I download a torrent and it reaches 50 to 60mbps (60mbps is my connection speed) the AC87U cpu shows nearly 100 percent core 1 and about 50 percent core 2, the less the speed less CPU load, net is enabled , when I try speedtest.net and get 60mbps CPU stays 0 percent. hope te to get some feedback on this thank you all
byt I have a tplink wdr3600 running ddwrt and when I download torrents Cpu does not load a bit

 

[System Error Message]

I believe the CPU load is because it has to handle storage, firewall and torrent client at the same time. I wouldnt say you have 100% CPU load, rather 75% but it appears that some program is using too much CPU just for listening or performing a task which the data gets dropped consistently (this could be for uploading where the torrent client is trying to push more data through than your internet allows). For example mikrotik's benchmark program will use all the CPU available even if the bandwidth used is below the full capacity of the CPU because without speed definitions it will try to spam as many packets as CPU allows but the NIC can only handle so much because it exceeds the wire capacity.

Try see if you can configure your internet speed settings somewhere in the router and make sure the torrent client uses it.

 

[Zirescu]

I suspect it's a bug in the Arm version of Transmission as it did the same thing with my AC87U and just bogged things down. Ended up setting up my RT-N66U in repeater mode and left transmission running on it with no issues.

 

[joegreat]

I suspect it's a bug in the Arm version of Transmission as it did the same thing with my AC87U and just bogged things down. Ended up setting up my RT-N66U in repeater mode and left transmission running on it with no issues.

Hi,

Keep in mind that the router CPU is rather slow (with default only 1000 MHz clock) and need to handle all parts of the Transmission demands without DMA or other accelerators.
The high CPU load is normal for Transmission or any other add-on applications on the small router CPU.

On my AC68U (overclocked to 1200 MHz) the picture is the same. See graphics below for the typical 1 CPU core with 100% load and the other one on lower utilization.


The full details of the load can be seen with Entware tool called dstat:

Output of command: dstat -cmsdrn --bw 5
----total-cpu-usage---- ------memory-usage----- ----swap--- -dsk/total- --io/total- -net/total-
usr sys idl wai hiq siq| used  buff  cach  free| used  free| read  writ| read  writ| recv  send
  1  1  81  16   0   1 |73.5M 7268k  108M 60.7M|6896k  247M|2430k  0 |15.4  0 |  39k  436k
  1  2  44  52   0   2 |73.3M 7308k  104M 65.3M|6896k  247M|2481k  0 |17.2  0 |  43k  449k
  0  1  39  59   0   2 |73.4M 7280k 95.0M 74.2M|6896k  247M|1586k  0 |20.6  0 |  38k  432k
  1  1  39  58   0   1 |73.4M 7276k 88.2M 81.0M|6896k  247M|1514k  0 |12.8  0 |  37k  445k
  0  1  44  54   0   1 |73.6M 7276k 77.8M 91.2M|6896k  247M| 889k  0 |9.60  0 |  39k  447k
  1  1  63  34   0   2 |73.4M 7280k 71.9M 97.3M|6896k  247M|1428k  0 |12.4  0 |  37k  412k
  1  1  87  11   0   1 |73.1M 7280k 81.7M 87.8M|6896k  247M|1882k  0 |14.6  0 |  35k  449k
  1  1  89   8   0   1 |73.3M 7280k 88.2M 81.1M|6876k  247M|1461k  0 |13.2  0 |  39k  443k
  1  1  89   9   0   1 |73.3M 7280k 95.1M 74.3M|6876k  247M|1414k  0 |11.4  0 |  38k  451k
  1  1  87  10   0   1 |73.3M 7280k  107M 62.7M|6876k  247M|2374k  0 |14.4  0 |  35k  444k
  1  1  62  34   0   2 |73.4M 7284k  103M 66.5M|6876k  247M|1547k  0 |11.0  0 |  40k  444k
  1  1  50  48   0   1 |73.5M 7228k 93.2M 76.0M|6876k  247M|1425k  0 |11.2  0 |  37k  449k
  1  1  50  49   0   1 |73.5M 7208k 83.8M 85.4M|6876k  247M|1466k  0 |11.6  0 |  39k  442k
  1  1  50  47   0   2 |73.5M 7208k 78.1M 91.2M|6876k  247M|1877k  0 |15.0  0 |  40k  442k

With kind regards
Joe

 

[Zirescu]

With the RT-N66U single CPU 600MHz, though I'm averaging around 33% CPU usage, transmission will peak at about 67% while downloads are happening. So it "seems" that the ARM build of Transmission is taxing things more. Before I moved to the AC87U I also had OpenVPN Client and Server running on the RT-N66U and still the router was responsive. AC87U got really sluggish so abandoned transmission on it. The other difference between my setup is the that the RT-N66U was using the SD card with Ext2, and with the AC87U I'm using USB3 Ext2.

 

[Chrysalis]

is a 68u @ the common 1.2ghz faster than a 87u at 1ghz?

by the way the cpu load may have been sirq/iowait related due to the asus caching bug.

what firmware are you using?

john fixed the bug in his firmware, not sure if merlin fixed in his or not. It is not fixed in asus own firmware.

 

[System Error Message]

All broadcom based ARM Chipsets use the same CPU, the difference are the clocks. Obviously the ASUS AC68U when overclocked is faster but the ASUS AC68U comes with slightly slower RAM.

 

[RMerlin]

All broadcom based ARM Chipsets use the same CPU, the difference are the clocks. Obviously the ASUS AC68U when overclocked is faster but the ASUS AC68U comes with slightly slower RAM.

AC56 and AC68 use a BCM4708 @ 800 MHz, while the RT-AC87U and RT-AC3200 use a BCM4709 @ 1 GHz. The BCM4709 also has support for Flow Accelerator.

 

[System Error Message]

AC56 and AC68 use a BCM4708 @ 800 MHz, while the RT-AC87U and RT-AC3200 use a BCM4709 @ 1 GHz. The BCM4709 also has support for Flow Accelerator.

Still in software based NAT flow accelerator isnt going to help so it just comes down to the CPU itself. The BCM4709 may have some additional hardware but the CPU is still the same. They have the same cache sizes, the same architectures, the same manufacturing process.

 

[kvic]

According to BRCM propaganda, https://www.broadcom.com/products/Wireless-LAN/802.11-Wireless-LAN-Solutions/BCM4707-4708-4709, flow accelerator is implemented in "hardware".

BCM4708 users don't have to feel being left out. It's a common feature across board. SoCs might have different features but the same CPU core.

Back to OP's issue, 0% cpu load at 60Mbps speedtest.net is a fairy tale*. On my AC56U with a 100Mbps WAN, during speediest.net, one core is about 40% load. Still lots of room to run demanding apps on the router. So check how your torrent write to storage and look for potential reduction on CPU load.

*fairy tale

BRCM claims 4707/08/09 all have hardware flow acceleration. How is it possible then 4709 as in AC87U zero cpu load at 60Mbps but 40% for 4708? Does Asus cripple h/w flow acceleration in driver for AC56U or some build config issue in 378.55 ?

 

[RMerlin]

BRCM claims 4707/08/09 all have hardware flow acceleration. How is it possible then 4709 as in AC87U zero cpu load at 60Mbps but 40% for 4708? Does Asus cripple h/w flow acceleration in driver for AC56U or some build config issue in 378.55 ?

FA is not available on the 4708 revision used by the AC56 and AC68. The firmware has code that queries the CPU revision, and determines based on that if FA is available or not.

 

[System Error Message]

My CCR1036 uses 0% CPU at 60Mb/s using software NAT lol than again it has 36 cores each faster than 2 ARM A9 cores at the same frequency and they even have IPSEC acceleration. I find hardware NAT or acceleration really unreliable because it only works in specific conditions.

The problem about ASUS routers is that they're very inconsistent. Both the AC87U and AC3200 have features that the rest of the pack even though they use CPU such as tend micro av, adaptive QoS and such. Flow acceleration would only affect hardware routing throughput or anything done with hardware.

 

[kvic]

FA is not available on the 4708 revision used by the AC56 and AC68. The firmware has code that queries the CPU revision, and determines based on that if FA is available or not.

Oh bugger!

@System Error Message Can you name three features from RouterOS that an average home will need? I'm genuinely curious as I've also seen ppl preaching about Fortinet, Draytek, Juniper... for home use.

 

[System Error Message]

like Juniper and cisco if you dont mind forgoing the router NAS and such its great for home use. It has very fine QoS control ( you can use priority + bandwidth control + trees), even change the algorithms used for each QoS rule.

it has RADIUS/hotspot server which is more secure than an AP with password which as we've discussed in this forum is bad for windows 10.

It has layer 7 firewall and configurable firewalls so you could for example stop kids from being able to chat on the internet at certain times by entering the software hash in the firewall and using the scheduler to enable/disable to rule. You have fine control over your network from layer 2 all the way to layer 7.(I use this to hijack DNS and NTP requests from LAN and redirect them to my router so no device can use another DNS server or NTP server while on my network and do a lot of other things)

Unlike every other home network you can secure your network against the pineapple hack that allows the hacker to access any of your accounts without having to log in (such as email, facebook, banking, etc).

You can tarpit hackers, DoS and other bad traffic so your internet doesnt get interrupted.

You can use the web proxy with transparent proxy configuration with cache as a way to reduce bandwidth usage for web browsing (the cache can be on ram, a FAT32 formatted usb attached hard drive, SD card, internal flash).

It has tftp server so you can use it for netbooting.

Technically you can use a usb attached hard drive as NAS/SAMBA but its not good in that area.

The only reason why im not using a cisco edgerouter in my room is because it requires 7KW. The maximum a mikrotik routerboard uses is 60W.

 

[kvic]

like Juniper and cisco if you dont mind forgoing the router NAS and such its great for home use. It has very fine QoS control ( you can use priority + bandwidth control + trees), even change the algorithms used for each QoS rule.

it has RADIUS/hotspot server which is more secure than an AP with password which as we've discussed in this forum is bad for windows 10.

It has layer 7 firewall and configurable firewalls so you could for example stop kids from being able to chat on the internet at certain times by entering the software hash in the firewall and using the scheduler to enable/disable to rule. You have fine control over your network from layer 2 all the way to layer 7.(I use this to hijack DNS and NTP requests from LAN and redirect them to my router so no device can use another DNS server or NTP server while on my network and do a lot of other things)

Unlike every other home network you can secure your network against the pineapple hack that allows the hacker to access any of your accounts without having to log in (such as email, facebook, banking, etc).

You can tarpit hackers, DoS and other bad traffic so your internet doesnt get interrupted.

You can use the web proxy with transparent proxy configuration with cache as a way to reduce bandwidth usage for web browsing (the cache can be on ram, a FAT32 formatted usb attached hard drive, SD card, internal flash).

It has tftp server so you can use it for netbooting.

Technically you can use a usb attached hard drive as NAS/SAMBA but its not good in that area.

The only reason why im not using a cisco edgerouter in my room is because it requires 7KW. The maximum a mikrotik routerboard uses is 60W.

Thanks for the details. None is particularly attractive for home use or for a soho environment with <20 users. Some mentioned features could be enabled in any linux based home routers.

I haven’t used any of these products but I would conjecture their firmware quality (by both good design and thorough tests) could be superior. Qualities such as consistency in performance, few regression bugs, and graceful degradation in adverse situations. These qualities aren’t going to be matched by home routers ever.

Enlighten me.

 

[Chrismallia]

Hi guys sorry for late reply and thank you all for your replies. I just want to say the the problem of high CPU is while using bit torrent on my PC not transmission on the router it self. I do not understand how downloading torrents on my PC effects the router with so high CPU usage

 

[L&LD]

Hi guys sorry for late reply and thank you all for your replies. I just want to say the the problem of high CPU is while using bit torrent on my PC not transmission on the router it self. I do not understand how downloading torrents on my PC effects the router with so high CPU usage

It is routing, so it is working (hard). Do you have any hardware acceleration enabled or disabled in the router?

 

[System Error Message]

Hi guys sorry for late reply and thank you all for your replies. I just want to say the the problem of high CPU is while using bit torrent on my PC not transmission on the router it self. I do not understand how downloading torrents on my PC effects the router with so high CPU usage

if you are using software NAT it is trying to keep track of all those connections at the same time. This is one thing that all consumer routers are bad at.

 

[Chrismallia]

if you are using software NAT it is trying to keep track of all those connections at the same time. This is one thing that all consumer routers are bad at.

I have NET acceleration enabled so I think it is using hardware net. 2 questions if how come a wdr3600 TPlink with ddwrt does not use all that cpu load for torrents it bearllu uses 8 percent. 2 I am replacing my consumer gear with enterprise, like I replaced my access points for XCLAIM XI3 and I can say that it handles everything much better including cloud manager , now am thinking of replacing my Asus router with PC running pfsence or clear os, any tips on what router to use or pc is much appreciated. I ask here for help coz I know you are very knowledgeable people

 

[kvic]

@Chrismallia How many connections do your torrent client reports when Asus is 100% load? If you can reproduce the situation, take a screenshot of Asus "top" output, in particular the two rows of CPU0&CPU1.

Firmware in consumer routers are crap. By that Asus is crap. I just don't believe AC87U is such incapable.