RPi -- Performance issues with SMB and WiFi-Networks

[astoeckel]

What did you do?
Playing videos (HD, various containers (mkv, ts, mp4, mov) all h264 at about 20 MBit/s) from a SMB share on a Raspberry Pi using
a1) the corresponding source option in XBMC.
b1) using the following bash command

mount -t cifs //remote-server/share mountpoint -o user=USER,password=PASS

and a file system source in XBMC.

The box is
a2) connected to the network via a 150 MBit WiFi dongle to a nearby WiFi-router
b2) connected via wired network to a laptop, which acts as a router and forwards all traffic to the network described in a2)

The network traffic is monitored on the SMB server.

What did you expect to happen?
As all videos play fine on the same hardware using a clean raspbian install (setup as in b1) and a2)) and I get a read throughput of 30 MBit/s, I expect the same when using OpenELEC in all the combined cases above.

What happened instead?

Smooth video playback is only possible in the combination b1) b2). The other combinations yield the following results:

a1), a2) 7-10 MBit/s throughput, buffers all 10 seconds, the throughput significantly increases while buffering and resumes to a smaller throughput when the playback resumes.

a1), b2) 11 MBit/s throughput, basically as above.

b1), a2) 17-20 MBit/s throughput, short stutters all 30 seconds, the throughput significantly increases while buffering and resumes to a smaller throughput when the playback resumes.

b1), b2) 25 MBit/s throughput, everything works as expected.

Conclusio

1. The results clearly show that using a user-space samba library is not a good option and (in my opinion) OpenELEC/XBMC should switch to using the kernel mode CIFS code instead.
2. The results show that OpenELEC/XBMC is CPU limited while playing back videos (which the simple omxplayer on raspbian isn't) and thus limits the WiFi transmission rate (probably caused by the WPA2 encryption/decryption process) -- this view is supported by the combination b1), b2) in which the very same network is used, with the very same dongle, yet the encryption/decryption is performed by the laptop.

OpenELEC version
Affects both 3.2.0 and 3.2.1

OpenELEC build
OpenELEC Stable - Raspberry Pi ARM Version:3.2.1 2013-09-28 22:29:55

OpenELEC arch
Raspberry PI, ARM v6hf

Additonal hardware setup information
WiFi-Dongle: Edimax EW7711UTn (Ralink RT2870), WPA-2 encrypted network

[jenkins101]

Hi,

Please read the contributing guide lines before posting issues, it is important that you follow the steps there so that we can help you.

[astoeckel]

Please read the contributing guide lines before posting issue

So I did. I've restructured my bug report "a little bit" to make it clearer to grasp, I hope now it fulfils your understanding of the guide lines.

[jenkins101]

We still need the logfiles zip though...

[astoeckel]

Here you go, log file for case a1, a2

http://somweyr.de/xbmc_3_2_1_stutter_wifi_smb_log.zip

Though I found the contents rather generic and not containing any information about the actual problem.

Unfortunately I'm uncapable (and unwilling) of creating logfiles for the other cases, as since the 3.2.1 update the RPi firmware/kernel is considerably broken and USB only works reliably approximately every fifth reboot -- but that's another issue.

[stefansaraev]

pi firmware issues should be fixed in 3.2.2, if it is related..

[astoeckel]

I just saw that you guys released a new version of OpenELEC, and yes, the firmware issues are fixed, yet the problem described above still persists.

Here is the log file for both a1, a2 and a1, b2 (playback once via the SMB option and once with the mount point -- which in my opinion could be automatically generated by OpenELEC -- as you can see in xbmc.log).

While the video was nearly unplayable in the first case (hangs every 5-10 seconds) it played relatively smoothly (after some buffering issues at the beginning) in the second case:

http://somweyr.de/xbmc_3_2_2_stutter_wifi_smb_log.zip

Thank you in advance and I hope that I've now provided all the data you'll need for finding a solution. Please let me know if I should try anything else or provide some more data.

[bluelight21]

I've got similar problems with Edimax, Edup and Logilink (all with 8188cus chipset). I'm using an complete different dongle now (Atheros ar9271 chipset), there is no performance issue at all.
Hope, that helped and that the issue will be solved soon, i like the small dongles.

[bluelight21]

seems to be fixed nox with update 3.2.4 (in my case).
Thank you very much

[ruoat]

I have had SMB performance problems since september-october. Originally I used raspbmc but after an update SMB started stuttering very much. I tried using OpenELEC 3.2.x but the same problem occurred. I found that OpenELEC 3.0.6 works fine but the xbmc is kind of old.

Yesterday I tried to upgrade to OE 3.2.4 but the same problem is still there. Then I wanted to see what happens if I put the kernel from 3.0.6 to OpenELEC 3.2.4 and that was a success! Now everything works fast and can use newer xbmc! I think kernel 3.10.x is somehow broken in RPI. The 3.6.11 kernel found from OE 3.0.6 works fine.

[bluelight21]

Sounds awesome. I've also tried to copy "kernel.img" from OE 3.0.6 to 3.2.4 yesterday, but my dongles were dead, when connected.
Second try: update OE with both "system_" files from 3.2.4 and "kernel_" files from 3.0.6 -> dead dongles (all tried out)
How have you done this?! o.O

[Spongman]

why was this closed. i can confirm this is still an issue.

[stefansaraev]

because it is an expected behaviour if using xbmc's integrated smb client over wifi. nothing we can fix on that hardware. you dont expect ~ 120mbps via wifi with samba shares in "userspace" right ?