Music/video occasionally skips

[Red Squirrel]

I noticed that recently if I'm listening to music or watching a video or any type of multimedia, the music will occasionally skip. I have a core i7 with 12GB of ram, there is absolutely no excuse for this to happen. I'm using xUbuntu. What would cause this and how can I make it stop? It seems this only started when I started folding again, but that's running at a low priority so it should not matter.

 

[Cerb]

Well, first, you could manually nice the folding process.

Consider turning on laptop mode, and adjusting vm.dirty_background_ratio, as well (/etc/sysctl.conf). If dirty_background_ratio is already fairly low, like 10-15, it probably isn't an issue (it's the maximum % of dirty pages allowed before a forced disk flush, which could cause pauses).

Then, look into getting a kernel with the CK patch set, for BFS. BFS is awesome, and it might be just what you need. How you should get it, though, I'm not sure. I'm too out of the Ubuntu tweaking loop for that.

If all else fails, try nicing the crap out of the folding processes.

 

[Red Squirrel]

Actually, if I just start it normally through a bash script, could it be that it's NOT running as low priority like I think it is? In Windows folding just automatically adjusts itself as low priority, but do I have to explicitly specify a nice value when starting it when in Linux? Maybe that's my issue, it could be that it's actually running at full tilt.

I just disabled it for now just to see if the issue happens again, so I can at least rule it out or in.

 

[jimmybgood9]

Check its niceness, assuming it is run with your user id, with:

ps a -o command,ni

if it's naughty, shut 'er down and start it nicely with:

nice -n 20 name-of-bash-script

 

[Nothinman]

Actually, if I just start it normally through a bash script, could it be that it's NOT running as low priority like I think it is? In Windows folding just automatically adjusts itself as low priority, but do I have to explicitly specify a nice value when starting it when in Linux? Maybe that's my issue, it could be that it's actually running at full tilt.

I just disabled it for now just to see if the issue happens again, so I can at least rule it out or in.

If it's not lowering it's priority on it's own then that would be a bug in the folding daemon. I doubt it isn't though because if it's spawning multiple threads to use all of your cores and running at the same priority as everything else you would have more noticeable issues than just skipping music.

Stuff like this is very hard to track down since it's so brief and intermittent. Do you have something running like Conky or Gkrellm so you can see if there's an I/O spike whenever it skips? Are there any log entries for you drives? Are they going to sleep? My first guess would be that the buffer in the audio or video player emptied and the drive took a second to respond.

 

[Red Squirrel]

So far so good with F@H off, I will give it more time so I can confirm, then I'll try playing with nice to see where that goes. I think I'll also run it with 6 cores instead of 8, so that might help too.