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destroyedlolo l33t
Joined: 17 Jun 2011 Posts: 846 Location: Close to Annecy (France)
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Posted: Fri Nov 18, 2011 11:48 pm Post subject: Disk throughput problem (DV capture). |
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Hello,
I'm facing some problems to capture DV videos using Kino : when data have to be writen to disk, the capture hangs fews seconds, the CPU usage fall from about 100% to 20% and the frames corresponding to this periodes are lost.
My configuration :
- venerable Athlon 1.1Ghz
- 1.5 Go memory, obviously not swaping
- system on an SCSI disk
- capture on an IDE (PATA) disk, read performances : 50 MB (I duno the write performances as Disk utils needs an empty disk).
Under Gentoo :
- Kino 1.3.4
- kernel 3.0.6
- LXTE/openbox
Under Ubuntu :
- Kino 1.3.3
- Kernel 2.6.31-23
- Gnome 2
I think it's a problem of configuration regarding disk access as I don't have the problem when booting on Ubuntu.
What I can say is writing internal is longer on Gentoo but time to write is longer as well (I think it's because more caches are used under Gentoo).
Any tip ?
Thanks
Laurent |
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John R. Graham Administrator
Joined: 08 Mar 2005 Posts: 10728 Location: Somewhere over Atlanta, Georgia
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Posted: Sat Nov 19, 2011 12:08 am Post subject: |
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What filesystem?
- John _________________ I can confirm that I have received between 0 and 499 National Security Letters. |
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destroyedlolo l33t
Joined: 17 Jun 2011 Posts: 846 Location: Close to Annecy (France)
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Posted: Sat Nov 19, 2011 12:22 am Post subject: |
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Ext4 (formated by Ubuntu's installer). |
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destroyedlolo l33t
Joined: 17 Jun 2011 Posts: 846 Location: Close to Annecy (France)
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Posted: Tue Nov 22, 2011 10:07 am Post subject: |
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Nobody has a tip ? It's very anoying
Bye
Laurent |
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destroyedlolo l33t
Joined: 17 Jun 2011 Posts: 846 Location: Close to Annecy (France)
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Posted: Tue Dec 13, 2011 11:15 am Post subject: |
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I found this interesting link, especially the part "Tuning Recommendations for write-heavy operations".
- can I change the proposed settings on the fly and how ?
- can I set them only for 1 disk (I don't think so, but who knows ...).
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destroyedlolo l33t
Joined: 17 Jun 2011 Posts: 846 Location: Close to Annecy (France)
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Posted: Wed Jan 25, 2012 12:03 am Post subject: |
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Well well well, no response good response as the French proverb says.
I did some tests on my own. And it seems :
Code: | sysctl -w vm.dirty_background_ratio=1 |
prevents this issue.
During my test, I can see some visual lags in Kino but "missed frame" counter stays at 0 and the resulting DV seems correct in VLC.
I think it's because my CPU power is on the edge but is still enough to avoid any loss
I'll try to retrieve 1h video and will report here, just in case it can help someone.
By the way, setting 1 is a bit brutal : I'm not sure intermediate will improve anything ... as I don't have enough horsepower to run anything in parallel ... |
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