GES 1.18.4, seeing CPU starvation (but not in 1.16.3)

[James]

> On 6 Oct 2021, at 3:30 am, David Ing via gstreamer-devel <gstreamer-devel at lists.freedesktop.org> wrote:
> 
> Basically I have a GstPipeline which contains a GESTimeline and then some third party encoders/muxers.
> 
> The problem is:
> 
> When the pipeline runs under Gstreamer 1.16.3, I typically reach 100% CPU usage (which is what I want).  But under Gstreamer 1.18.4, it is more like 40% CPU usage (and the job takes longer).
> 
> Extra details:
> 
> I observed the problems on both platforms that I checked.
> 		• Windows MSVC
> 		• Fedora (via gst-build)
> I have some files on a gfolder here to illustrate the problem.
> 		• cpu_under_utilization.png shows CPU usage over time:
> 			• The first bump is the pipeline running under Gstreamer 1.16.3
> 			• The next bump is the pipeline running under Gstreamer 1.18.4
> 		• playing_1.16.3.svg shows the pipeline on 1.16.3
> 		• playing_1.18.4.svg shows the pipeline on 1.18.4 (it looks the same).
> My questions are:
> 	• Does anyone know of some changes (perhaps related to threading) that might be causing this issue?
> 	• What is a good way to diagnose this problem?
But I have a. pipeline the uses mp4mux to mux v4l2 and pulse audio. Under 1.16 it stutters terribly but under 1.18 it is smooth. 
Course tools like htop but even tools like gnome-system-monitor don't show cpu usage at 100%
James