[FFmpeg-user] ffmpeg multithreaded performance bad for specific physical machine

Sven C. Dack sven.c.dack at sky.com
Fri Oct 7 01:50:40 EEST 2016

On 06/10/16 21:25, P. Remek wrote:
> Hi,
> I have some update regarding my original question: we figured that if
> we switch off linux watchdog with "echo 0 > proc/sys/kernel/watchdog"
> the multithreaded behaivor and performance of ffmpeg goes back to
> normal. We don't know yet why is that because on our two socket
> physical machine the performance is normal even with this switched on.
> Any ideas?
> Regards
I fear your problem goes beyond the scope of this mailing list. When you are 
using the exact same binary on both machines then it's very likely not a problem 
caused directly by ffmpeg, but one coming from the environments in which it is 
run in.

Can you say for sure that this is a problem specific only to ffmpeg and have you 
had a look at other software and found a similar problem?
Are you using the same CPU governor on both machines? ... Use the performance 
Are you using the same kernel on both machines? ... Use the same task scheduling 
algorithm, the same frequency governor, etc..

One could come up with quite a list of questions which needed to be answered. I 
suggest you start by looking at everything related to energy-saving and turn it 
off in order to get a less dynamic behaviour from your OS and thereby a more 
fixed environment before you start comparing these.

Don't forget to look at BIOS settings, too.

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