Talk:Handbrake userjob

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Revision as of 17:23, 31 May 2012 by Wagnerrp (Talk | contribs)

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I'm on gentoo, mythbackend is started as root, so this user job will run as root as well.

What? No it isn't. The stock init script for Gentoo setuids to the mythtv user account. wagnerrp 06:43, 9 May 2012 (UTC)
You are right. I will correct this. - reznor

Detecting already running

On my system (mythtv 0.25, ubuntu 12.04), user jobs are launching as `sh -c /opt/myth_make_x264.pl...` and there is another entry in `ps aux` for the resultant perl process. The script finds that shell process as another entry and thinks there is another script running. I modified to the below, which seems to work:

 my $curProcs = `ps aux | grep $scriptName | grep -v grep | grep -v "sh -c" | wc -l`;

This is my first user job, so maybe I've done something strange...but I don't think so. Bygottski 05:42, 31 May 2012 (UTC)

I'm not really sure what the intended purpose of that code is anyway. The jobqueue has an internal task limit that will prevent too many instances from being run simultaneously. I don't know why the script would need its own semaphore. wagnerrp 07:57, 31 May 2012 (UTC)
The purpose for this is limiting handbrake encoding jobs. Handbrake by default utilizes all cpu cores of the system for encoding. This code is intended to prevent heavy load on all cores by limiting simultaneous handbrake encoding jobs. I think there has been a handbrake command line switch to limit cpu core usage which is gone. Another approach would be using cpulimit. - reznor
Yes. Why do you need to limit simultaneous encoding jobs within the script? The jobqueue already does that, with a maximum number of simultaneous jobs it will run per host, defaulting to one, and configurable in mythtv-setup. Once that limit has been reached, it will not start a new task until a previous one has terminated. wagnerrp 17:23, 31 May 2012 (UTC)
Handbrake only supports threads when the encoder itself supports threads. Threading parameters must be passed directly into the encoder with that '-x' argument you use for the encoding options. By default, x264 will use 1.5x the number of logical CPUs on your system, meaning hyperthreaded is counted. You can adjust this by adding a 'threads=<n>' parameter into your encoding options. wagnerrp 17:23, 31 May 2012 (UTC)