Bug 1383575

Summary:	Xorg High CPU Usage Fedora 24
Product:	[Fedora] Fedora	Reporter:	isrvr-lptp1 <organicchemistry_01>
Component:	xorg-x11	Assignee:	X/OpenGL Maintenance List <xgl-maint>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	high	Docs Contact:
Priority:	unspecified
Version:	24
Target Milestone:	---
Target Release:	---
Hardware:	x86_64
OS:	Linux
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Last Closed:	2016-10-15 05:57:29 UTC	Type:	Bug
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Description isrvr-lptp1 2016-10-11 06:14:12 UTC

Description of problem:

Xorg consumes too much CPU that is a consistent 24% on one core + Distributed 10% on a Dual Xeon E5 2670 Configuration. Considering I have is a 32T/16 Core machine with each core clocked at 2.7 GHz, Linux shouldn't be taxing my system. 

Xorg consumes too much CPU cycle, as compared to Fedora 21 which consumes close to 0 upto 11% on a much weaker machine, 4T/2C 1.6GHz processor.

System is:

Processor: 2x Intel Xeon E5 2670 2.7GHz 8C/16T
GPU: Nvidia GTX 1060 6Gig
MB: Asrock EP2C602 4L/D16
Mem: 32G Samsung ECC Server type
SDD: Samsung Evo 850 500G (Not the buggy Evo 840 of course)
HDD: Hitachi 1T

Version-Release number of selected component (if applicable):


How reproducible:
Install Fedora 24, watch the Xorg usage

Steps to Reproduce:
1. Install Fedora 24
2. Use TOP command to see the usage
3. Use System Monitor

Actual results:
Xorg consumes a consistent CPU usage of 24% on one core + Distributed 10%

Expected results:
Expecting to have just 0-1% CPU usage for Xorg

Additional info: N/A

Comment 1 isrvr-lptp1 2016-10-15 05:57:29 UTC

Ok, I found the culprit, its NOT technically the Xorg Bug but more like a GDM Issue, GDM launches its Own separate Session other than Login-User (Which is Admin) session, resulting to two Xorg process and two gnome-shell process and basically almost all other process duplicated! Alternate fix is to add

[daemon]
WaylandEnable=false

in the /etc/gdm/custom.conf

Restart, then manually killing the duplicate process launched by GDM or More precisely kill the Xorg and gnome-shell GDM duplicate process.

It is easy to look at system monitor to see which is the Xorg and Gnome-Shell process launched by the GDM.

Kill them and Done, system will be back to normal, no other thing gets affected when killing this duplicate process except if you did not add WaylandEnable=false.

However, this is not really a solution but just a work around, I am intending to file this Bug to GDM.

More advice from developer would also be appreciated.

Summary: 

1. Not an XORG Bug, but more likely a GDM Bug
2. Fix CPU usage of xorg from 24% down to 0 - 0.7%
3. Fix GPU utilization from 28% to 0%
4. Huge improvements huh.