MythTV General Discussion and Support

[HyRax1]

Originally Posted by kizzav

I'm 2 for 2! Fixed an audio/slo-mo playback issue a few posts above & now your image tearing issue. WTF!?!?

I know... I'm scared too.

[dave-]

Originally Posted by HyRax1

Clearly the NVidia compositing option is totally separate to Compiz compositing.

LOL I didn't even suggest that because I figured you'd have been all over it already hehe

[HyRax1]

Originally Posted by dave-

LOL I didn't even suggest that because I figured you'd have been all over it already hehe

Well I had everything else related to compositing disabled, and I never realized that NVidia's compositing was a separate function to Compiz's compositing. Ah well, you learn something new everyday!

[kizzav]

I'm hoping to buy a GT210 & another Hauppauge MCE remote kit tomorrow, but I'm also contemplating on buying some more RAM for my backend.

MythTV claims that 99% of my 2GB DDR3 1333 (sadly because of the nature of the mobo, downgrades to 1066, single channel I suspect) is being used, leaving a few MB's left or less.

However, the System Monitor tells a different story, nothing like the info MythTV is producing.

Is it worth getting another 2GB DDR3 or not?

On a side note, if I'm watching a recording on the ION (frontend only) & my brother is watching recordings via MythWeb, is there any explanation as to why the MythWeb stream would freeze every so often for half a second?

[daehenoc]

Hey, does anyone know if mythfront end is available on the powerpc architecture? It doesn't seem to be available??

[HyRax1]

Originally Posted by kizzav

MythTV claims that 99% of my 2GB DDR3 1333 (sadly because of the nature of the mobo, downgrades to 1066, single channel I suspect) is being used, leaving a few MB's left or less.

However, the System Monitor tells a different story, nothing like the info MythTV is producing.

Is it worth getting another 2GB DDR3 or not?

Check what top says in a terminal. If there is a significant amount of swap being used, then yes - consider more RAM. If no swap is being used, or very little is being used, then you don't need any more.

Originally Posted by kizzav

On a side note, if I'm watching a recording on the ION (frontend only) & my brother is watching recordings via MythWeb, is there any explanation as to why the MythWeb stream would freeze every so often for half a second?

Are you reading from a single drive on your backend? If so, then you should make sure you have AHCI enabled in your backend's BIOS to help prevent requests spamming the drive. Remember that the Frontend buffers video as it plays while playing from MythWeb more or less relies on the buffering your media player will do.

Originally Posted by daehenoc

Hey, does anyone know if mythfront end is available on the powerpc architecture? It doesn't seem to be available??

Not that I'm aware of - support for the PowerPC in general appears to be pretty low now.

[kizzav]

Originally Posted by HyRax1

Check what top says in a terminal. If there is a significant amount of swap being used, then yes - consider more RAM. If no swap is being used, or very little is being used, then you don't need any more.

While playing a 720p recording on the ION, this is the backend's results....


Click to view full size!

On a side note, what is it you do to kill all the fancy desktop effects?

[HyRax1]

Originally Posted by kizzav

While playing a 720p recording on the ION, this is the backend's results....

pix

A whole 3.5MB is going to swap. Woo... You don't need an upgrade.

Originally Posted by kizzav

On a side note, what is it you do to kill all the fancy desktop effects?

System menu->Preferences->Appearance->Visual Effects->None.

[kizzav]

Originally Posted by HyRax1

A whole 3.5MB is going to swap. Woo... You don't need an upgrade.

That 3.5MB was used earlier this afternoon.

If my calculations are correct however, I only have 138MB of RAM remaining.

Originally Posted by HyRax1

System menu->Preferences->Appearance->Visual Effects->None.

That's it. Now I can remote desktop via a GUI.

Btw, now I only have 51MB remaining.


Click to view full size!

EDIT: Checked again, now only 35MB.

[HyRax1]

Originally Posted by kizzav

If my calculations are correct however, I only have 138MB of RAM remaining.

But the RAM used is not being used for apps or data - look at your cache value - it's nearly 1.5GB. The reality is that the system itself is really only using 500MB of RAM out of your 2GB. If it didn't cache data, it would either be reloaded from HDD or put into swap, which is slower.

If you bring up the System Monitor applet on one of your Gnome panels, you will see the Memory meter uses dark green to indicate actual memory used and light green to indicate cached data.


Click to view full size!

In the above example, 60% of my system RAM is being used as cache. 30% is actual apps and data and the last 10% is not utilised at the moment. Not shown is swap, because in this case I simply don't need swap at all with 8GB RAM.

[SteveMenheere]

As I understand it. most linux systems will report nearly 100% memory use. Swap memory in use is the key think

This is what mine reports. (combined fe/be, non VDPAU, 1 SD program being watched on fe) I have never had any problem - even with multiple programs recording & commercial flagging. Been running with 2G memory for many years

top - 22:08:34 up 7 days, 12:53,  2 users,  load average: 0.73, 0.45, 0.62
Tasks: 198 total,   1 running, 197 sleeping,   0 stopped,   0 zombie
Cpu(s):  9.8%us,  1.5%sy,  0.0%ni, 86.1%id,  2.5%wa,  0.0%hi,  0.1%si,  0.0%st
Mem:   2056696k total,  2027616k used,    29080k free,    19608k buffers
Swap:  6022136k total,   119012k used,  5903124k free,  1349512k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
 9122 myth      20   0  796m 200m  12m S   36 10.0  63:40.05 mythfrontend.re
 1043 root      20   0  266m  52m  10m S    9  2.6  58:38.68 Xorg
 1234 mysql     20   0  396m  61m 3684 S    0  3.1  38:36.83 mysqld
    1 root      20   0 23840 1456  788 S    0  0.1   0:01.25 init
    2 root      20   0     0    0    0 S    0  0.0   0:00.01 kthreadd
    3 root      RT   0     0    0    0 S    0  0.0   0:00.03 migration/0
    4 root      20   0     0    0    0 S    0  0.0   0:07.86 ksoftirqd/0
    5 root      RT   0     0    0    0 S    0  0.0   0:00.00 watchdog/0
    6 root      RT   0     0    0    0 S    0  0.0   0:00.03 migration/1
    7 root      20   0     0    0    0 S    0  0.0   0:04.95 ksoftirqd/1
    8 root      RT   0     0    0    0 S    0  0.0   0:00.00 watchdog/1
    9 root      RT   0     0    0    0 S    0  0.0   0:00.16 migration/2
   10 root      20   0     0    0    0 S    0  0.0   0:31.52 ksoftirqd/2
   11 root      RT   0     0    0    0 S    0  0.0   0:00.00 watchdog/2
   12 root      RT   0     0    0    0 S    0  0.0   0:00.10 migration/3
   13 root      20   0     0    0    0 S    0  0.0   0:24.28 ksoftirqd/3
   14 root      RT   0     0    0    0 S    0  0.0   0:00.00 watchdog/3

[elvis]

Originally Posted by HyRax1

But the RAM used is not being used for apps or data - look at your cache value - it's nearly 1.5GB. The reality is that the system itself is really only using 500MB of RAM out of your 2GB. If it didn't cache data, it would either be reloaded from HDD or put into swap, which is slower.

Freeing cache memory is quite a resource-inexpensive task. It makes no sense to leave memory around with nothing in it (after all, you paid for it, so you may as well use it to its fullest capacity).

If a file, program or library is loaded into memory, it may as well stay there even if the user is finished with it. As long as nothing else needs that memory, then it's not wasted. If something does need the memory, removing the old data is very quick (nanoseconds). If that same program/file/library is opened again, then a big chunk of the data is still in memory, and it saves the system having to load everything from the orders-of-magnitude-slower hard disk.

It's a bit of a trap for people coming over from Windows to get used to. At first glance it does appear that Linux is very memory hungry. But once you learn to ignore the "cache" statistic, you see what's really going on.

For what it's worth, even some very big companies get this wrong. VMWare *STILL* thinks that if cache+buffers+app memory is greater than 90%, it needs to throw up a warning in vCentre. Clearly the great minds in VMWare's dev team didn't get the memory from the Linux/UNIX guys 20-something years ago. Just another great piece of programming from that shoddy company.

Moving on.... I also recommend Linux users stop using "top". It's bloody awful. Instead, switch to "htop":

http://htop.sourceforge.net/

Ubuntu/Mythbuntu users simple type "sudo apt-get install -y htop" at a prompt.

For starters, it does a much better job of visually breaking down application, cache and buffer memory in colour, and shows you what your applications are actually using. That's just one of the million things it does better than the legacy "top".

Notice the yellow part of the memory counter in this image, which represents cache (and can happily be ignored when looking at system memory usage from a resource management point of view):


I install htop on every system I get my hands on. Everyone from junior sysadmins to application developers prefer it so much more, as it actually shows some useful (and customisable) information.

[Swathe]

I agree, htop is bloody brilliant, been using it for a couple of years now.

[HyRax1]

Originally Posted by elvis

Freeing cache memory is quite a resource-inexpensive task. It makes no sense to leave memory around with nothing in it (after all, you paid for it, so you may as well use it to its fullest capacity).

Oh yeah, I wasn't suggesting that his cache needed to be freed - I was just pointing out that was where he memory was being used (as a Good Thing^TM).

Originally Posted by elvis

Moving on.... I also recommend Linux users stop using "top". It's bloody awful. Instead, switch to "htop":

Awesome - I love it! Thanks!


Click to view full size!

That yellow bar shows memory vs cache in the same way as the Gnome System Monitor applet. Perfect!

[3five1]

HI

I finally got around to purchasing a Asus MyCinema U3100 Mini usb tv tuner card for my (see sig) htpc, I tried installing it but am having trouble getting it to run & recognise, am a novice at installing Command line drivers & programs.

I followed the instruction booklet but it didn't help, it written for PCLinuxOS but I would have thought it to run o.k in Ubuntu as well. I have mine plugged in straight from the stick to the antenna wall socket, hope this is right ...would appreciate as much info and tips as possible to get it going?

Thank you!