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Limit post processing stage's cpu usage

Posted: July 14th, 2011, 4:59 pm
by Arman_UV
I'm running SABnzbd on an old iMac. I'm looking for a way to limit the cpu usage of sabnzbd subprocesses when it starts to post process and unrar the downloaded files. Whenever I'm watching a movie and it starts stuttering, I know it's because SABnzbds is processing a file.
I found this terminal tool called cputhrottle that can do exactly what I want except that it uses the PID of the process to limit its usage. The problem is that the PID of the unrar process changes for each new download. it's simply not worse the hassle to look up the PID and run the command every time a new file finishes downloading.
Does anybody know of a simpler method to do this?

Re: Limit post processing stage's cpu usage

Posted: July 14th, 2011, 5:42 pm
by shypike
The problem is not in the CPU probably.
SABnzbd already uses "nice" to tame the CPU.
It's much more likely that the disk is the bottleneck.
Unfortunatey OSX has no tools to lower disk-priority.

Re: Limit post processing stage's cpu usage

Posted: July 14th, 2011, 6:24 pm
by Arman_UV
shypike wrote:The problem is not in the CPU probably.
SABnzbd already uses "nice" to tame the CPU.
It's much more likely that the disk is the bottleneck.
Unfortunatey OSX has no tools to lower disk-priority.
I don't think that's the case here because all my movies are on a NAS drive connected directly to the iMac while SABnzbd's download location is on the main internal hard drive.

Re: Limit post processing stage's cpu usage

Posted: July 15th, 2011, 4:13 am
by shypike
Unrar unpacks from your internal disk to your external NAS.
Of course this affects disk access.

You can add a pause-postprocess and resume-postprocess event in the scheduler.
That will prevent any post-processing during the paused hours.

Re: Limit post processing stage's cpu usage

Posted: July 18th, 2011, 5:57 pm
by Arman_UV
shypike wrote:Unrar unpacks from your internal disk to your external NAS.
Of course this affects disk access.

You can add a pause-postprocess and resume-postprocess event in the scheduler.
That will prevent any post-processing during the paused hours.
I believe you misunderstood me. Both SABnzbd's incomplete and complete download folders are on the internal disk. I copy the movies to the NAS manually.

Re: Limit post processing stage's cpu usage

Posted: July 19th, 2011, 1:11 am
by shypike
Still post-processing is quite system load,
So you'd best not do that while watching movies.
SABnzbd already lowers it's own prio as much as it can,
But par2 and unrar are hard to tame.

Re: Limit post processing stage's cpu usage

Posted: July 21st, 2011, 8:51 pm
by Arman_UV
that's what i was afraid of... :(
Thanks for your help!