Re: [gentoo-user] I want to play movies without hangs

[Volker Armin Hemmann <volkerarmin@googlemail.com>]

Am Montag, 7. Mai 2012, 14:41:34 schrieb Alex Schuster:
> Some while ago, I wrote:
> 
> [
> mplayer stutters when I/O is going on, even hangs for seconds when I do a
> dd if=/dev/zero of=somefile bs=1M
> ]
> 
> > Urs Schutz writes:
> > > Just an idea: Is the disk OK? Replace /dev/sda with your
> > > disk...
> 
> [...]
> 
> > > I had a bad disk here, which resulted in slow IO, but not
> > > complete failure. Smart detected this immediately. Sorry,
> > > I do not know how to check disks with LVM.
> > 
> > Didn't you get errors in yslog then?
> > 
> > I also thought about swapping the system drive - I have a larger backup
> > drive, with nearly identical logical volumes on it, where I make
> > backups with rdiffbackup. So even the content is identical, except for
> > an additional rdiff-backup directory containing the increments. So all
> > I have to do is to echange the two volume group names, reboot, and the
> > system will run from the other drive. But I very much doubt this will
> > help, transfer speed looks okay to me, around 100 MB/s with dd.
> 
> I did it in another way. I created a large file system (LVM) on my 2nd
> drive, copied /, /usr, /var, /opt and /home over. My whole system is
> encrypted, but I omitted this, just to make sure this is not the
> bottleneck.
> 
> Alas, no change. Another thing I tried was to change the SATA mode in my
> BIOS from AHCI to whatever the other option is. This did not help either.
> 
> Now this is really annoying. I watch small clips mostly, and can live
> with that, and when I want to watch stuff with others, I copy the file to
> tmpfs, which seems to help a lot.
> 
> But now I found another solution: NOT USING KDE.
> 
> When X crashed (trying to make the old Unreal game play), I fired up
> another window manager, and when I played a video in there, there was no
> problem at all. So, I have another workaround.
> 
> But does anyone have an idea, why running KDE is the problem? Disabling
> desktop effects does not help.

nepomuk/virtuoso running in the background

whenever you have more than 1 process doing IO linux sucks ass.

Now, you write to a partition, nepomuk tries to index it (1 read) and your 
player reading the video file (2nd read). Interactivity is shot.

Pause/kill nepomuk and look if it helps.

For me the worst case is: writing lots of files on a usb device - sucks 
everywhere, even on a vt.

-- 
#163933