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Am 07.05.2012 18:26, schrieb Volker Armin Hemmann: |
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> Am Montag, 7. Mai 2012, 14:41:34 schrieb Alex Schuster: |
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>> Some while ago, I wrote: |
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>> |
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>> [ |
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>> mplayer stutters when I/O is going on, even hangs for seconds when I do a |
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>> dd if=/dev/zero of=somefile bs=1M |
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>> ] |
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>> |
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>>> Urs Schutz writes: |
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>>>> Just an idea: Is the disk OK? Replace /dev/sda with your |
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>>>> disk... |
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>> |
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>> [...] |
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>> |
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>>>> I had a bad disk here, which resulted in slow IO, but not |
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>>>> complete failure. Smart detected this immediately. Sorry, |
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>>>> I do not know how to check disks with LVM. |
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>>> |
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>>> Didn't you get errors in yslog then? |
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>>> |
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>>> I also thought about swapping the system drive - I have a larger backup |
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>>> drive, with nearly identical logical volumes on it, where I make |
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>>> backups with rdiffbackup. So even the content is identical, except for |
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>>> an additional rdiff-backup directory containing the increments. So all |
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>>> I have to do is to echange the two volume group names, reboot, and the |
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>>> system will run from the other drive. But I very much doubt this will |
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>>> help, transfer speed looks okay to me, around 100 MB/s with dd. |
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>> |
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>> I did it in another way. I created a large file system (LVM) on my 2nd |
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>> drive, copied /, /usr, /var, /opt and /home over. My whole system is |
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>> encrypted, but I omitted this, just to make sure this is not the |
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>> bottleneck. |
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>> |
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>> Alas, no change. Another thing I tried was to change the SATA mode in my |
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>> BIOS from AHCI to whatever the other option is. This did not help either. |
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>> |
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>> Now this is really annoying. I watch small clips mostly, and can live |
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>> with that, and when I want to watch stuff with others, I copy the file to |
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>> tmpfs, which seems to help a lot. |
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>> |
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>> But now I found another solution: NOT USING KDE. |
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>> |
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>> When X crashed (trying to make the old Unreal game play), I fired up |
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>> another window manager, and when I played a video in there, there was no |
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>> problem at all. So, I have another workaround. |
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>> |
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>> But does anyone have an idea, why running KDE is the problem? Disabling |
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>> desktop effects does not help. |
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> |
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> nepomuk/virtuoso running in the background |
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> |
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> whenever you have more than 1 process doing IO linux sucks ass. |
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> |
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> Now, you write to a partition, nepomuk tries to index it (1 read) and your |
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> player reading the video file (2nd read). Interactivity is shot. |
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> |
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> Pause/kill nepomuk and look if it helps. |
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> |
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> For me the worst case is: writing lots of files on a usb device - sucks |
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> everywhere, even on a vt. |
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> |
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|
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Maybe changing the kernel io scheduler will help? |
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|
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# /usr/src/linux/Documentation/block/switching-sched.txt |
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# /usr/src/linux/Documentation/block/deadline-iosched.txt |
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# /usr/src/linux/Documentation/block/cfq-iosched.txt |
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