AC-87U high CPU usage

[Dmytro]

Hello everyone. I have a AC-87U router with merlin's firmware 384.13_2. There is a WD My Passport 25E2 4TB HDD with hfs+ connected through USB3. Samba is enabled.

Amazon Fire TV is connected to TV and Kodi is installed on it. When I'm trying to watch a movie in Kodi through SMB from HDD connected to router I see squares, video crackling, etc. During this period one of the cores of router gives 100% CPU usage

what I've tried
1. Tried to watch through VLC on amazon fire tv - the same problem
2. Tried to use VLC on Iphone - the same problem
3. Tried to use another video file - sometimes problem exists sometimes not. So it depends on a video
4. Tried to watch the problem video file through SMB from my laptop - everything is ok

Maybe someone has ideas about what is going on? I would be really appreciated.

P.S. memory usage goes up to 95% when I try to fast forward the video or just watch it. After video stops playing memory usage returns to 55-60% in 3-5 minutes

P.S2 made some experiments after writing this post. So, in general, I get squares after using fast-forward. If video is played without fast-forward in 90% of cases it runs smoothly.

 

[dosborne]

Just my $0.02, but it sounds like you need a NAS or at least something more powerful than your router for what you want to do. I know my opinion varies from a few others here but file sharing off the router, although technically possible, is not really what people expect or think it was designed to be. Yes, you can share some docs, run a few scripts, pass a few files back and forth, but when you start getting into video playback and other intensive tasks you really should look at solutions that were designed with that primary function in mind.

Personally, I try to OFFLOAD everything and anything so that my router only has to worry about its primary function, routing.

Even moving to a $20 raspberry Pi would be a better option IMO. (Not saying it would or would not perform any better (although I'd guess it would), but at least your internet access would not be affected).

The type of file access, sustained load, the HDD performance, the file system type and many other factors are critical as to whether or not file sharing off the router can be done successfully or not. For some it works, for many it does not.

 

[lindros2]

Agree with above. Using a HDD for video streaming in today’s world is putting too much load on a lower priority service for the router. I use a drive as occasional backup, and even then, i set it to USB 2.
A NETGEAR NAS isn’t bad, but something like PLEX might also work well.

 

[Dmytro]

thanks @dosborne @lindros2 for your opinion. I understand that router is not best hardware for video streaming. But even in this case I wonder why it _can_ stream 10GB files without any problems with fast-forward etc and _can't_ stream smaller files. Basically on low level it should only position the HDD to needed sector and read data. So it should do the same as for 10GB files and for 1.5GB files with any codec.

Also I understand that router could be slow and could use 100% CPU for all files with all sizes and codecs.

What I want to know why video file matters for CPU load ?

P.S. for only routing it is enough rt-66u I bought ac-87u not only for AC networks but for using it as small NAS and everything has been ok for the last 2 years. recently it started to be slow with some video files

 

[dosborne]

The size of the file is not always that important. The encoding, bit rate etc can have a huge impact as can the video player itself.

 

[carpov alexandru]

Personally, I try to OFFLOAD everything and anything so that my router only has to worry about its primary function, routing.

Why would anyone buy an expensive router and use it just for routing? A lower priced router would do just fine for "just routing".
I have a tp-link n750, as my second router, costs about 25$ second hand , and it can download at 880mbps.
Also, my ISP rents a router for 2$ a month, and that router hits 930mbps download; saw it with my own eyes.
I bought an RT-AC1900U, to have things enabled on it, not to use it as i would use a 2$/month router.

 

[elbubi]

Just my 2 cents.
I have a 87U also, running mediaserver with samba on usb2 (256gb pendrive) and Downloadmaster on usb3 (256gb pendrive).
Never ever experienced hicups or bottlenecks even under heavy torrent downloading with downloadmaster (+60GB file) while streaming 4k movies on dlna/samba server.
I guess something else besides router overload might be wrong on your side (codecs, video player, etc.)

Ps: As a sidenote, I use my router for anything I need to, I love to masacrate it! =P

 

[Dmytro]

@elbubi the funny thing is I tried to stream 10gb file - the CPU is loaded for 100% but fast-forward and etc works just great. I would say that there is a problem with Amazon fire TV or Kodi when I have problems. But iPhone works the same. In this case, we could say - man, you have a bad video file with bad codec, etc. Ok. But it works great when I run it from SMB from my MacBook ??

I mean, basically I just want to understand what is going on. On a low level

Such a lot of questions

 

[Dmytro]

@dosborne I understand this. In case of codec matters why this codec works bad from the router and good from MacBook?

 

[elbubi]

@Dmytro
To isolate the problem, I would try to copy a "problematic" video file to Fire's TV internal/external storage and try to reproduce the issue by playing it locally.
If the issue persists, then its something to do with the file (codec, container, etc) or the video player you are using. If not, then its the streaming through router and needs further investigation.

Besides that test, did you try both 2.4 and 5.4 bands with same results?

Regards!

 

[Dmytro]

@elbubi nice idea. thanks

so I've checked
1. HDD connected to MacBook + smb - no problems
2. HDD connected to FireTV like external storage - no problems
3. HDD connected to USB 2.0 port on router - problems as described above
4. HDD connected to USB 3.0 on the router - problems as described above
5. MicroSD card inserted into Fire TV - no problems

Unfortunately, my FireTV supports only 2.4 range.

Codec which has problems


The other file codec, which has no problem

 

[elbubi]

It would by nice if you can try with 5.0Ghz device, if signal is strong, throughput is much much wider.
Codec wise, it doesn't seem to be anything out of the ordinary (H264 es pretty standard)
Here I paste my 2.4, 5.0 and mediaserver actual config just for reference if you want to try them.
Btw, high memory usage is pretty normal behaviour if don't have regular flush enabled (which I don't, default is set to disabled also)

Cheers!

 

[Dmytro]

It would by nice if you can try with 5.0Ghz device, if signal is strong, throughput is much much wider.
Codec wise, it doesn't seem to be anything out of the ordinary (H264 es pretty standard)
Here I paste my 2.4, 5.0 and mediaserver actual config just for reference if you want to try them.
Btw, high memory usage is pretty normal behaviour if don't have regular flush enabled (which I don't, default is set to disabled also)

Cheers!

I've tried to view the video from iPhone 8 using VLC player - same problem behavior