Memory management woes

[aws910]

Whenever a memory-intensive process is run, it encounters many errors. I have a macbook pro penryn(?) with 4GB memory. The way this manifests itself is when I process a large file using ffmpeg: the output has a scratchy sound. Another way I've noticed this is when I try to play a 5-track recording in ardour - sound output skips a lot. This system is supposedly top-of-the-line, so I don't think it's a horsepower issue. For some reason, I can't get it to use the swapfile.

I posted more detail in another forum on this site, but I guess I posted in the wrong place because I got no response:
http://ubuntuforums.org/showthread.php?p=5786837#post5786837

[Yannick Le Saint kyncani]

Hi aws910,

- First, your system only use 3G ram when you have 4G. I suppose that's because you've installed 32bits ubuntu. 64bits ubuntu would use all 4G ram (assuming you have a 64bits cpu).

- Out of your 3G ram, 2G is used for cache, the remaining by your various programs. This is a very healthy situation. It means you won't gain anything by using 4G ram instead of 3G.

- As for the audio skipping from time to time, you may try the linux-rt kernel (sudo apt-get install linux-rt, and then reboot and choose the realtime kernel). And it may not change anything.

- You could also paste the output of "top", so that we can see if your system is on its knees cpu/io-wise.

Just my .02$

[aws910]

Thanks a lot, I'll try that tonight and see if it helps.

[cyberdork33]

macs tend to have issues with the realtime kernel, but goodluck.

[aws910]

Wow, you were right. Installed the RT kernel and output is still scratchy.

Here's the output of top at idle:
top - 10:52:27 up 1:53, 3 users, load average: 0.33, 1.33, 1.91
Tasks: 167 total, 2 running, 165 sleeping, 0 stopped, 0 zombie
Cpu(s): 11.2%us, 2.6%sy, 0.0%ni, 84.8%id, 0.0%wa, 1.0%hi, 0.3%si, 0.0%st
Mem: 3063428k total, 794204k used, 2269224k free, 13756k buffers
Swap: 8193140k total, 40020k used, 8153120k free, 304564k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
6524 mr 20 0 88464 29m 14m S 0 1.0 4:39.43 nautilus
6839 mr 20 0 269m 150m 24m S 4 5.0 4:36.08 firefox
6166 root 20 0 899m 67m 41m R 10 2.3 3:57.28 Xorg
5874 root 20 0 13344 1068 732 S 2 0.0 2:16.58 pommed
1487 root -51 -5 0 0 0 S 1 0.0 1:31.24 IRQ-16
6593 mr 20 0 130m 89m 42m S 7 3.0 1:11.76 compiz.real
1454 root -51 -5 0 0 0 S 0 0.0 0:53.27 IRQ-19
6 root -51 -5 0 0 0 S 1 0.0 0:52.93 softirq-timer/0
19 root -51 -5 0 0 0 S 0 0.0 0:29.01 softirq-timer/1
23 root -51 -5 0 0 0 S 0 0.0 0:28.53 softirq-tasklet
10 root -51 -5 0 0 0 S 0 0.0 0:22.28 softirq-tasklet
202 root 15 -5 0 0 0 S 0 0.0 0:19.32 kswapd0
9391 root 20 0 0 0 0 S 0 0.0 0:18.36 pdflush
6520 mr 20 0 15200 2660 1764 S 0 0.1 0:17.79 gnome-screensav
22 root -51 -5 0 0 0 S 0 0.0 0:16.39 softirq-block/1
6522 mr 20 0 44640 23m 14m S 0 0.8 0:15.62 gnome-panel
9 root -51 -5 0 0 0 S 0 0.0 0:15.40 softirq-block/0
6812 mr 20 0 70252 30m 18m S 0 1.0 0:15.30 pidgin
1618 root -51 -5 0 0 0 S 0 0.0 0:12.96 IRQ-20
5668 root 20 0 1872 540 444 S 0 0.0 0:07.70 dd
200 root 20 0 0 0 0 S 0 0.0 0:07.59 pdflush
1567 root -51 -5 0 0 0 S 0 0.0 0:07.02 IRQ-17
5670 klog 20 0 3804 2720 424 S 0 0.1 0:06.46 klogd
6754 mr 20 0 20936 8368 7068 S 0 0.3 0:05.58 multiload-apple
6613 mr 20 0 44140 15m 9.9m S 0 0.5 0:05.08 nm-applet
6743 mr 20 0 20780 11m 7012 S 0 0.4 0:04.88 gtk-window-deco
5524 root 15 -5 0 0 0 S 0 0.0 0:03.98 kondemand/0
6504 mr 20 0 26832 4084 3284 S 0 0.1 0:03.73 pulseaudio
5616 syslog 20 0 1936 680 532 S 0 0.0 0:03.27 syslogd
11 root -51 -5 0 0 0 S 0 0.0 0:03.17 softirq-sched/0
6496 mr 20 0 40072 10m 8080 S 0 0.3 0:02.86 gnome-settings-
10740 mr 20 0 37128 16m 10m S 0 0.6 0:02.47 sensors-applet
6597 mr 20 0 37132 16m 9m S 0 0.5 0:02.37 update-notifier
6941 mr 20 0 28684 13m 7824 S 0 0.5 0:01.88 notification-da
26 root -51 -5 0 0 0 S 0 0.0 0:01.81 softirq-rcu/1
13 root -51 -5 0 0 0 S 0 0.0 0:01.79 softirq-rcu/0
6432 mr 20 0 7304 4396 1904 S 0 0.1 0:01.64 gconfd-2
3181 root 16 -4 2420 968 384 S 0 0.0 0:01.54 udevd
6064 root 20 0 3420 1144 988 S 0 0.0 0:01.54 hald-addon-stor
24 root -51 -5 0 0 0 S 0 0.0 0:01.48 softirq-sched/1
5944 haldaemo 20 0 6492 4548 3632 S 0 0.1 0:01.47 hald
11243 mr 20 0 80804 21m 11m S 3 0.7 0:01.47 gnome-terminal
2163 root 15 -5 0 0 0 S 0 0.0 0:01.37 scsi_eh_0
72 root -51 -5 0 0 0 S 0 0.0 0:01.23 IRQ-9
1 root 20 0 2844 1692 544 S 0 0.1 0:01.05 init
2954 root 15 -5 0 0 0 S 0 0.0 0:00.84 kjournald
6635 mr 20 0 22032 2668 2204 S 0 0.1 0:00.81 gvfsd-trash
2509 root 15 -5 0 0 0 S 0 0.0 0:00.70 usb-storage
6594 mr 20 0 23172 8572 6296 S 0 0.3 0:00.66 bluetooth-apple
6756 mr 20 0 30588 13m 8860 S 0 0.4 0:00.60 fast-user-switc
2157 root 15 -5 0 0 0 S 0 0.0 0:00.59 ata/1
11237 mr 20 0 44668 18m 11m S 0 0.6 0:00.57 gedit
2156 root 15 -5 0 0 0 S 0 0.0 0:00.55 ata/0
6612 mr 20 0 24420 12m 7168 S 0 0.4 0:00.53 python
8 root -51 -5 0 0 0 S 0 0.0 0:00.52 softirq-net-rx/
21 root -51 -5 0 0 0 S 0 0.0 0:00.51 softirq-net-rx/
6021 root 20 0 3416 1156 1004 S 0 0.0 0:00.50 hald-addon-inpu
6530 mr 20 0 41544 3560 2448 S 0 0.1 0:00.42 bonobo-activati
30 root -2 -5 0 0 0 S 0 0.0 0:00.41 events/1
11275 mr 20 0 2440 1168 856 R 1 0.0 0:00.41 top



And the output of top while processing said wmv->wav ffmpeg task:

top - 10:56:28 up 1:57, 3 users, load average: 2.70, 1.85, 1.96
Tasks: 168 total, 1 running, 167 sleeping, 0 stopped, 0 zombie
Cpu(s): 6.4%us, 3.6%sy, 0.0%ni, 14.2%id, 73.2%wa, 1.0%hi, 1.5%si, 0.0%st
Mem: 3063428k total, 1136592k used, 1926836k free, 11604k buffers
Swap: 8193140k total, 40020k used, 8153120k free, 636968k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
11375 mr 20 0 14756 2564 1368 D 6 0.1 0:08.26 ffmpeg
6166 root 20 0 899m 67m 41m S 4 2.3 4:11.01 Xorg
6839 mr 20 0 269m 150m 24m S 3 5.0 4:45.84 firefox
2954 root 15 -5 0 0 0 D 2 0.0 0:01.73 kjournald
5874 root 20 0 13344 1068 732 S 2 0.0 2:20.99 pommed
9 root -51 -5 0 0 0 S 1 0.0 0:16.37 softirq-block/0
1487 root -51 -5 0 0 0 S 1 0.0 1:34.05 IRQ-16
6593 mr 20 0 130m 89m 42m S 1 3.0 1:16.06 compiz.real
6 root -51 -5 0 0 0 S 1 0.0 0:54.30 softirq-timer/0
19 root -51 -5 0 0 0 S 1 0.0 0:29.86 softirq-timer/1
22 root -51 -5 0 0 0 S 1 0.0 0:17.19 softirq-block/1
11378 mr 20 0 2440 1160 852 R 1 0.0 0:00.03 top
10 root -51 -5 0 0 0 S 0 0.0 0:23.05 softirq-tasklet
23 root -51 -5 0 0 0 S 0 0.0 0:29.34 softirq-tasklet
1454 root -51 -5 0 0 0 S 0 0.0 0:53.91 IRQ-19
1567 root -51 -5 0 0 0 S 0 0.0 0:07.21 IRQ-17
1618 root -51 -5 0 0 0 S 0 0.0 0:13.34 IRQ-20
5670 klog 20 0 3804 2720 424 S 0 0.1 0:06.64 klogd
11359 root 20 0 0 0 0 D 0 0.0 0:00.13 pdflush
1 root 20 0 2844 1692 544 S 0 0.1 0:01.05 init
2 root 15 -5 0 0 0 S 0 0.0 0:00.00 kthreadd
3 root RT -5 0 0 0 S 0 0.0 0:00.29 migration/0
4 root RT -5 0 0 0 S 0 0.0 0:00.00 posix_cpu_timer
5 root -51 -5 0 0 0 S 0 0.0 0:00.00 softirq-high/0
7 root -51 -5 0 0 0 S 0 0.0 0:00.00 softirq-net-tx/
8 root -51 -5 0 0 0 S 0 0.0 0:00.52 softirq-net-rx/
11 root -51 -5 0 0 0 S 0 0.0 0:03.24 softirq-sched/0
12 root -51 -5 0 0 0 S 0 0.0 0:00.00 softirq-hrtimer
13 root -51 -5 0 0 0 S 0 0.0 0:01.83 softirq-rcu/0
14 root RT -5 0 0 0 S 0 0.0 0:00.00 watchdog/0
15 root 10 -10 0 0 0 S 0 0.0 0:00.00 desched/0
16 root RT -5 0 0 0 S 0 0.0 0:00.10 migration/1
17 root RT -5 0 0 0 S 0 0.0 0:00.00 posix_cpu_timer
18 root -51 -5 0 0 0 S 0 0.0 0:00.00 softirq-high/1
20 root -51 -5 0 0 0 S 0 0.0 0:00.00 softirq-net-tx/
21 root -51 -5 0 0 0 S 0 0.0 0:00.51 softirq-net-rx/
24 root -51 -5 0 0 0 S 0 0.0 0:01.49 softirq-sched/1
25 root -51 -5 0 0 0 S 0 0.0 0:00.00 softirq-hrtimer
26 root -51 -5 0 0 0 S 0 0.0 0:01.85 softirq-rcu/1
27 root RT -5 0 0 0 S 0 0.0 0:00.00 watchdog/1
28 root 10 -10 0 0 0 S 0 0.0 0:00.00 desched/1
29 root -2 -20 0 0 0 S 0 0.0 0:00.30 events/0
30 root -2 -5 0 0 0 S 0 0.0 0:00.42 events/1
31 root 15 -5 0 0 0 S 0 0.0 0:00.00 khelper
66 root 15 -5 0 0 0 S 0 0.0 0:00.15 kblockd/0
67 root 15 -5 0 0 0 S 0 0.0 0:00.17 kblockd/1
70 root 15 -5 0 0 0 S 0 0.0 0:00.12 kacpid
71 root 15 -5 0 0 0 S 0 0.0 0:00.00 kacpi_notify
72 root -51 -5 0 0 0 S 0 0.0 0:01.27 IRQ-9
157 root 15 -5 0 0 0 S 0 0.0 0:00.00 kseriod
199 root -2 -5 0 0 0 S 0 0.0 0:00.00 krcupreemptd
202 root 15 -5 0 0 0 S 0 0.0 0:19.64 kswapd0
203 root 15 -5 0 0 0 S 0 0.0 0:00.00 aio/0
204 root 15 -5 0 0 0 S 0 0.0 0:00.00 aio/1
804 root -51 -5 0 0 0 S 0 0.0 0:00.00 IRQ-8
1442 root 15 -5 0 0 0 S 0 0.0 0:00.00 ksuspend_usbd
1443 root 15 -5 0 0 0 S 0 0.0 0:00.00 khubd
2156 root 15 -5 0 0 0 S 0 0.0 0:00.57 ata/0
2157 root 15 -5 0 0 0 S 0 0.0 0:00.61 ata/1
2158 root 15 -5 0 0 0 S 0 0.0 0:00.00 ata_aux

I see ffmpeg alternating between R and D status...

[Yannick Le Saint kyncani]

Yep, your system is spending all its time waiting for I/O (you have 73% WAiting for i/o).

Basically, you're screwed, because the so-called solutions are :

1- Copy all your data in a tmpfs and create the converted file in this tmpfs, but you can only do that if the size of wmv+wma is less than half your ram (which never happens).

2- Enhance the performance of I/O (buy faster drives, ...) but that means a lot of money.

3- Or, my preferred solution, run i/o and cpu intensive operations when you're not using your box (at night).


No 3 being the most practical solution, obviously.

[aws910]

Ouch. I was told this was a brand new, top of the line macbook pro... Core 2 duo T8300 w 4gb ram, and when I ran the test, most other programs were closed. Should I stop running Compiz and Firefox?

[Yannick Le Saint kyncani]

Should I stop running Compiz and Firefox?

You could try, nothing to loose, right :)

I don't think it will make any difference though. Your cpus are 15% idle and you have unused ram, so I think your problem is I/O-related.

If your wmv you want converted is less than 1G, you could try this though :

- Open a terminal.

- cd /the/directory/which/holds/the/wmv/file/

- cat mywmvfile.wmv >/dev/null

Then try the encoding again. This would fill your ram with the wmv file in cache. Then, assuming the wmv file is small enough and you still have ram free, the entire wmv file will stay cached and ffmpeg won't have to read it from the disk.

Your best bet would be to run cpu, ram and i/o intensive applications at night though.

[aws910]

Thanks for the ideas!

I closed firefox, disabled compiz, cached the file, then tried ffmpeg'ing it, no luck. Tried recompiling ffmpeg with --enable-extra-warnings, thought that option and the rebuild with the rt headers might solve it, but no luck. Maybe I'll try again tomorrow.

I like your idea of "doing it at night", don't know why it took so long to realize what you were saying :) ... I do have another machine I could script the recordings/transcoding on, run the job at night, then just copy it to a usb stick and go.