Video skips after I turn on a MD

[nosebreaker]

I just figured out why my core seems to randomly stop skipping.  It appears that after I turn on a diskless MD it slows down the core.  At first I thought it was just MKV files, but it seems any video will skip.  I can reset the core and then its fine!  Any ideas what to do to fix this?  I am still running 0704.

[Murdock]

0704 or 0710?

[nosebreaker]

Um, whatever the release before 0810, I thought it was 0704 like that video.  When I do uname it says:
Linux dcerouter 2.6.22-14-generic

[Murdock]

I don't recall what 704 was, though you could always type 'lsb_release -a' to find out the version you're currently on.

Does the skip occur during the MD boot process and then stop, or does it continue to skip after the MD is done?

[nosebreaker]

It skips after the MD is done booting, and doesn't stop until its been rebooted.  It's still somewhat watchable, the framerate drops to like 10fps so the jitter is obvious (audio is fine) but since I don't always want to wait 5-10min for a reboot I just tough it out.  I usually only have 1 MD at a time running, so I never noticed if the core MD was slow or not until later.

Murdock:
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 7.10
Release:        7.10
Codename:       gutsy

[Murdock]

What do your system stats look like when you're experiencing the issue (either via vmstat or top or htop)?

I'm wondering if you have alot of high i/o waits?

[nosebreaker]

top - 13:35:47 up  1:00,  1 user,  load average: 0.55, 0.54, 0.46
Tasks: 234 total,   2 running, 232 sleeping,   0 stopped,   0 zombie
Cpu(s):  3.5%us,  3.2%sy,  0.0%ni, 91.2%id,  0.8%wa,  0.2%hi,  1.2%si,  0.0%st
Mem:   3107020k total,   909824k used,  2197196k free,    19144k buffers
Swap:  4305380k total,        0k used,  4305380k free,   460736k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
16800 root      15   0 56552 3248 2600 S    3  0.1   1:48.17 ZWave
17118 root      15   0 41928  11m 2400 S    2  0.4   2:19.75 motion
12961 root      14  -1  321m  21m 6020 S    1  0.7   0:19.42 Xorg
13111 root      15   0 14572 7984 6260 S    1  0.3   0:03.85 xfwm4
5738 mysql     15   0  153m  57m 5636 S    0  1.9   1:50.67 mysqld
10440 root      15   0  2920  940  596 S    0  0.0   0:00.04 screen
10441 root      25   0  2788 1416 1024 S    0  0.0   0:03.84 StorageDevices_
18269 root      24   0 74192  29m  10m S    0  1.0   0:07.80 Photo_Screen_Sa
    1 root      16   0  3356 2208  532 S    0  0.1   0:01.18 init
    2 root      10  -5     0    0    0 S    0  0.0   0:00.00 kthreadd
    3 root      RT  -5     0    0    0 S    0  0.0   0:00.01 migration/0
    4 root      34  19     0    0    0 S    0  0.0   0:00.00 ksoftirqd/0
    5 root      RT  -5     0    0    0 S    0  0.0   0:00.00 watchdog/0

I'm not at home and not watching anything now, but that is what it has right now for top.  Not sure if that helps or not.

[Murdock]

The system is pretty idle there what does it look like when you're experiencing the issue? I wouldn't *think* this would be a programming based issue if your the only one hitting it, that's why i'm wondering if it's system utilization.

[Murdock]

I had some video skipping when i was running UI2 with alpha blending, after turning off the alpha blending the skipping stopped. Which UI are you running?

[nosebreaker]

I am running UI2 but these systems are hefty enough to handle it with no problems.  If you look at my profile on the wiki you can see what I have.

UPDATE - it happens even when I don't boot a MD, I had only been using the core for the past week or so and it started happening again.  So this is a red herring, something else must be causing it to skip.

[Murdock]

Are you using ui2 with alpha blending, or just ui2? If you're using the alpha blending piece try shutting that off and retesting to see if that clears it up.

[nosebreaker]

Turns out this was a red herring, it happens even if I don't turn on a MD.  xine is using about 40% cpu and mysqld is using about 5-10%, other than that nothing is doing much!  A reboot still fixes it though.

[nosebreaker]

Are you using ui2 with alpha blending, or just ui2? If you're using the alpha blending piece try shutting that off and retesting to see if that clears it up.

The alpha blending is what made me decide to go with LMCE!  The problem is that it takes weeks for it to start skipping, it isn't easy to duplicate, I don't know what triggers it.

[nosebreaker]

So my system is doing the skipping again, here is my top output:

top - 12:45:08 up 11 days, 18:46,  1 user,  load average: 1.45, 0.76, 0.50
Tasks: 241 total,   1 running, 240 sleeping,   0 stopped,   0 zombie
Cpu(s): 37.3%us,  1.7%sy,  0.0%ni, 61.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:   3107020k total,  2318944k used,   788076k free,   198408k buffers
Swap:  4305380k total,    37960k used,  4267420k free,  1068564k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
20564 root      20   0  512m 385m 9376 S   62 12.7   2604:03 Xine_Player
18164 ruser     15   0  2496 1248  876 R    3  0.0   0:00.03 top
18795 root      15   0 35640 5640 1892 S    3  0.2   0:00.01 motion
19543 root      15   0 42848  14m 2496 S    3  0.5 647:49.90 motion
    1 root      17   0  3352 2208  532 S    0  0.1   0:01.51 init
    2 root      10  -5     0    0    0 S    0  0.0   0:00.84 kthreadd
    3 root      RT  -5     0    0    0 S    0  0.0   0:13.11 migration/0
    4 root      34  19     0    0    0 S    0  0.0   0:00.54 ksoftirqd/0
    5 root      RT  -5     0    0    0 S    0  0.0   0:00.00 watchdog/0
 
The video I am playing is very low quality, yet it is using 60% cpu!  I'd say it is about 400x300 at most, the total file is only 150mb or so.  If I boot into Vista I can watch HD 1080 video without skipping!

[nosebreaker]

I rebooted, and the video plays fine.  There is nothing over 2% cpu usage!