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On Tuesday 19 August 2008 18:35:18 Håkon Alstadheim wrote: |
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> When I say "tune" I mean things like picking a resolution and a |
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> deinterlace method for video that is as good as possible, while still |
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> leaving enough headroom to avoid uneven playback. |
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Ah, that puts a different spin on it. Those things are outside my area of |
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expertise |
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> Given that a schedule |
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> update or a backup run might kick in at a bad time despite all efforts |
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> to write a good crontab, knowing when to stop is not always easy. I run |
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> all system tasks under "nice ionice -c3", and they will still cause |
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> hiccups if the system is maxed out. |
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nice, ionice and all other tools that look like they might affect scheduling |
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are actually just hints to the Linux kernel, which is free to completely |
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ignore them (and very often does). In fact, for a great many years in the |
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early days, nice actually did nothing of any consequence at all... :-) |
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nice exists because it is a long-standing Unix tool and on early Unixes it did |
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do what the man page implies. Things have changed and kernel writers realise |
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that. |
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re crons, there's not a lot you can do when vixie-cron decides to kick in. |
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However, there are other cron daemons about. I've never used it, but I recall |
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a discussion here a year ago about fcron which looks like it might suit your |
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needs. IIRC you can configure it to delay a cron job while a specified process |
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is running and all manner of other cool stuff suitable for desktops |
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> mplayer kept saying my system was too slow, while the cpu was idling at |
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> 20%. Turns out top was correct in that instance, mplayer was |
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> misinterpreting input data, trying to play back at half the intended |
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> frame-rate. Now I'm past that hurdle and adding deinterlacing and other |
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> filters. I'll just have to hold back on the temptation to go all out on |
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> the filter options :-) |
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I find mplayer often gets it wrong, and the console messages about audio |
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drivers being responsible for slowdowns are often true. I also usually find |
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that a slow machine that has a light load is often due to I/O blocking. Have |
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you looked into this yet? |
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-- |
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alan dot mckinnon at gmail dot com |
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