Am 07.05.2012 18:26, schrieb Volker Armin Hemmann: > 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. >
Maybe changing the kernel io scheduler will help? # /usr/src/linux/Documentation/block/switching-sched.txt # /usr/src/linux/Documentation/block/deadline-iosched.txt # /usr/src/linux/Documentation/block/cfq-iosched.txt
