UNIX for Dummies Questions & Answers

Hi, I'm John_giova and I'm new in this Forum. Sorry my english, it's not my first language.

So, I'm trying to check the CPU utlization during the video encoding and decoding (making a comparison between SW and HW ) using the SAR tool. According to a past thread I saw as CPU utilization I should have to consider %user+%nice+%system.
The questions are 2:
The first, more important, is: is the video co-decoding a user activity, and I need to consider just %user+%nice as CPU load or I have to consider also %system?
Second: why when I do the SW encoding almost the total load is on %nice column(few in user) and when I do HW encoding and both SW and HW decoding the main utilization CPU is in the %user column and the %nice column is totally zero??

I hope I have been clear enough, I'm not really pacticed with this.

It's really hard to say without knowing what software you're using, or even what operating system you're using. The difference between 'user' and 'nice' is priority, somehow the software encoding is being run at low priority.

You should consider user + system + nice, though I'd assume video encoding would be almost completely user-time cpu computation, with only a little time spent in the kernel for I/O.

Yes, I forgot the software, I'm using GStreamer. Thanks very much for your answer, and, if I can ask you, about the fact that in a case there is more nice CPU % and in the others is zero and the most is %user you can tell me something?

Like I said, the %nice is probably because that particular mode is run at low priority.

To know why it's run at low priority, I'd have to look deep into gstreamer.

Yes, sorry, in Italy it's 23:40 and I'm not so "awake", eheh. So, the most important is that I have to consider the sum of user, nice and system. Thanks again, Corona.