DisplayLink Software - High CPU on MBA

dlinkdaddy · 09-04-2019, 11:31 PM

Quote:

Originally Posted by rich2019

This is repeatable on my MacBook Pro 2012 using Mac Screen Sharing to VNC to another machine. If the other machine is doing frequent updates (eg like some redrawing of part of a webpage, a very common occurence), then the CPU will go insane on my Mac.

I have looked at Activity Monitor to see that, in this order, the following are consuming CPU:
a. WindowServer (insanely active)
b. DisplayLinkManager (insanely active)
c. Screen Sharing (insanely active)
d. kernel_task
e. DisplayLinkUserAgent (not very busy)

I'm running DisplayLink version 5.2 under Mojave 10.14.6 on the 2017 13'' MacBook Pro and I'm experiencing the exact same issues under the same circumstances.

tommiy · 09-16-2019, 09:35 AM

I have a 2017 4 USB-C port MAC and my work forces me to use a Dell 3100 dock. I get the same problems every single day. Thinking it was some hing else I had loaded I took the trouble on the weekend to do a complete backup and reinstall of Mojave. Nothing else installed except Mojave and Displaylink. Sure enough after about 10hrs I get 150% for DisplayLink and another 35% for window driver CPU utilisation. This happens on driver version 5.0, 5.1 and 5.1.1. I stay away fro driver 5.2 because when I use that and its not connected to a display link dock external thunderbolt monitors do not work.

So, I guess the answer is it is not just you on 14.6 that has this problem but there are a number of us that have noticed there PC go insane with displaylink drivers. I notice because I work in a quite environment and I hear the fans go off I can almost guarantee what is happening. I meant to actually save a log to send to support today when it occurred but unfortunately I also need to work. maybe tomorrow when it happens.

Short answer is not much you can do about it as it would appear its a displaylink problem and maybe only with 14.6. You can try swapping Users when it happens I found that this causes it to go away....or 2 reboots seems to fix it as well (often 1 reboot does nothing).

Best of luck don;t see this ever getting fixed....Catalina I think will be an experience an a half for Displaylink.

tommiy · 09-18-2019, 08:30 AM

Definitely a DisplayLink issue. I have run my MAC for 2 days without the DisplayLink driver installed but using thunderbolt monitors without experiencing the issue. Within 10 minutes of attaching a DisplayLink dock the DisplayLink Manager goes to above 100% CPU and Windowserver >35%. Disconnecting the dock removes the DisplayLink Manager CPU use but Windowsserver remains at 35%. The only way to restore is to reboot multiple times, typically twice, for some reason once is not enough.

So reinstalling Mojave as a clean install and blowing away all my previous data has had no effect on the outcome.

No responses from DisplayLink I see....shame.

tommiy · 09-19-2019, 09:21 PM

I have successfully worked for 2 days without having DisplayLink Manager going to 150% CPU resulting in WindowServer blowing up by uninstalling display link and using a friends little dock for dual displays. Seems this is more reliable than displaylink and is relatively portable. No further issues of high CPU and fans turning on so far in 2 days which simply has not happened with DisplayLink since I completely reinstalled Mojave. Seems that this is the best way to resolve given lack of response from Displaylink.

So in short, fresh clean install of Mojave and displaylink results in high CPU utilisation on Displaylink Manager and also WindowsServer. Unplugging the DisplayLink dock sees the DisplayLink Manager CPU usage go away but WindowServer remains high. You need to reboot twice to recover WindowServer for some reason. Logs sent to Displaylink. No response.

Solution: replace displaylink dock.

tommiy · 09-24-2019, 08:24 PM

Sadly the issue returned.

I've trashed Mojave again and reinstalled office and a few minor other applications. Without DisplayLink installed and at 17:39:26 each day the WindowServer process goes high CPU to approximately 40% and remains there until 18:10.

I suspect that with Displaylink Drivers installed the problem is more pronounced because of the fact that I think the Drivers are trying to stay in sync with the DisplayServer. This means that the DisplayLink Drivers hit about 140-160% CPU while WindowServer hits 40%. Heats the MAC like no tomorrow.

I've been trying to get to the bottom of what is happening but appears that something sets the kernel off and it says that it is flipping the Display. The logs for this vary between occurring every 20ms to far less than.that. I've got a message over at Apple Communities but absolutely no responses at all. Its getting detailed. Last resort is back to High Sierra and surrender on Mojave to see if the problem goes away. This does not seem like a Displaylink issue but it is the obvious visible impact.

https://discussions.apple.com/thread/250645982

tommiy · 09-25-2019, 09:04 PM

I've spent many hours at this and trying to address what the problem is.

To cut a long story short, after discussions with Apple over the fact that the DisplayServer in 10.14.6 18G95 apparently gets confused and generates large amounts of kernel DisplayBuffer Logging trying to switch between display resolutions of the same resolution (see previous link) apple suggested disabling Night Shift.

Its only been 1 day but yesterday is the first day where my MAC has not ran WindowServer at high CPU utilisation early in the morning or late in the afternoon.

At a guess here, it appears that there may be a bug in 18G95 where the OS is attempting to perform Night Shift on the external Monitor and is falling for some reason. The OS continues to try for 30 minutes from my experience. During this timeframe you can stop, reboot the MAC and the high CPU utilisation continues. If you look in the syslog (log show --debug) you can see the kernel logging messages about switching resolution and the time difference between these messages vary from sub millisecond logs to in the early teens.

With DisplayLink Drivers loaded this problem appears to be associated with Displaylink as it consumed approximately 3x the CPU than the windowServer process. I'd have a guess and say this is because of all the proposed resolution switches being attempted by the kernel.So Displaylink goes to 120-160% CPU utilisation and WindowServer goes to 35-40%.

I have my fingers crossed that the disabling of the night shift holds for the coming days. However, I'll also be feeding the outcomes back to Apple as I do use the feature and would like to see a working Catalina.

Hope that may assist others. Cross the fingers. I can say reinstalling 18G95 did not change anything in my experience.

tommiy · 09-26-2019, 08:13 PM

With NightShift turned off I have had 2 days without High CPU issues on WindowServer process (and subequently the 100% CPU utilisation by DisplayLink). Seems that Apple is correct and they have broken the NightShift process on 18G95. Server me right for installing the supplementary updates.

No patch expected from Apple on Mojave. Catalina is a hope they may fix it.

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09-16-2019, 09:35 AM	#2
tommiy Member Join Date: Mar 2018 Posts: 92	I have a 2017 4 USB-C port MAC and my work forces me to use a Dell 3100 dock. I get the same problems every single day. Thinking it was some hing else I had loaded I took the trouble on the weekend to do a complete backup and reinstall of Mojave. Nothing else installed except Mojave and Displaylink. Sure enough after about 10hrs I get 150% for DisplayLink and another 35% for window driver CPU utilisation. This happens on driver version 5.0, 5.1 and 5.1.1. I stay away fro driver 5.2 because when I use that and its not connected to a display link dock external thunderbolt monitors do not work. So, I guess the answer is it is not just you on 14.6 that has this problem but there are a number of us that have noticed there PC go insane with displaylink drivers. I notice because I work in a quite environment and I hear the fans go off I can almost guarantee what is happening. I meant to actually save a log to send to support today when it occurred but unfortunately I also need to work. maybe tomorrow when it happens. Short answer is not much you can do about it as it would appear its a displaylink problem and maybe only with 14.6. You can try swapping Users when it happens I found that this causes it to go away....or 2 reboots seems to fix it as well (often 1 reboot does nothing). Best of luck don;t see this ever getting fixed....Catalina I think will be an experience an a half for Displaylink.

09-18-2019, 08:30 AM	#3
tommiy Member Join Date: Mar 2018 Posts: 92	Definitely a DisplayLink issue. I have run my MAC for 2 days without the DisplayLink driver installed but using thunderbolt monitors without experiencing the issue. Within 10 minutes of attaching a DisplayLink dock the DisplayLink Manager goes to above 100% CPU and Windowserver >35%. Disconnecting the dock removes the DisplayLink Manager CPU use but Windowsserver remains at 35%. The only way to restore is to reboot multiple times, typically twice, for some reason once is not enough. So reinstalling Mojave as a clean install and blowing away all my previous data has had no effect on the outcome. No responses from DisplayLink I see....shame.

09-19-2019, 09:21 PM	#4
tommiy Member Join Date: Mar 2018 Posts: 92	I have successfully worked for 2 days without having DisplayLink Manager going to 150% CPU resulting in WindowServer blowing up by uninstalling display link and using a friends little dock for dual displays. Seems this is more reliable than displaylink and is relatively portable. No further issues of high CPU and fans turning on so far in 2 days which simply has not happened with DisplayLink since I completely reinstalled Mojave. Seems that this is the best way to resolve given lack of response from Displaylink. So in short, fresh clean install of Mojave and displaylink results in high CPU utilisation on Displaylink Manager and also WindowsServer. Unplugging the DisplayLink dock sees the DisplayLink Manager CPU usage go away but WindowServer remains high. You need to reboot twice to recover WindowServer for some reason. Logs sent to Displaylink. No response. Solution: replace displaylink dock.

09-24-2019, 08:24 PM	#5
tommiy Member Join Date: Mar 2018 Posts: 92	Sadly the issue returned. I've trashed Mojave again and reinstalled office and a few minor other applications. Without DisplayLink installed and at 17:39:26 each day the WindowServer process goes high CPU to approximately 40% and remains there until 18:10. I suspect that with Displaylink Drivers installed the problem is more pronounced because of the fact that I think the Drivers are trying to stay in sync with the DisplayServer. This means that the DisplayLink Drivers hit about 140-160% CPU while WindowServer hits 40%. Heats the MAC like no tomorrow. I've been trying to get to the bottom of what is happening but appears that something sets the kernel off and it says that it is flipping the Display. The logs for this vary between occurring every 20ms to far less than.that. I've got a message over at Apple Communities but absolutely no responses at all. Its getting detailed. Last resort is back to High Sierra and surrender on Mojave to see if the problem goes away. This does not seem like a Displaylink issue but it is the obvious visible impact. https://discussions.apple.com/thread/250645982

09-25-2019, 09:04 PM	#6
tommiy Member Join Date: Mar 2018 Posts: 92	I've spent many hours at this and trying to address what the problem is. To cut a long story short, after discussions with Apple over the fact that the DisplayServer in 10.14.6 18G95 apparently gets confused and generates large amounts of kernel DisplayBuffer Logging trying to switch between display resolutions of the same resolution (see previous link) apple suggested disabling Night Shift. Its only been 1 day but yesterday is the first day where my MAC has not ran WindowServer at high CPU utilisation early in the morning or late in the afternoon. At a guess here, it appears that there may be a bug in 18G95 where the OS is attempting to perform Night Shift on the external Monitor and is falling for some reason. The OS continues to try for 30 minutes from my experience. During this timeframe you can stop, reboot the MAC and the high CPU utilisation continues. If you look in the syslog (log show --debug) you can see the kernel logging messages about switching resolution and the time difference between these messages vary from sub millisecond logs to in the early teens. With DisplayLink Drivers loaded this problem appears to be associated with Displaylink as it consumed approximately 3x the CPU than the windowServer process. I'd have a guess and say this is because of all the proposed resolution switches being attempted by the kernel.So Displaylink goes to 120-160% CPU utilisation and WindowServer goes to 35-40%. I have my fingers crossed that the disabling of the night shift holds for the coming days. However, I'll also be feeding the outcomes back to Apple as I do use the feature and would like to see a working Catalina. Hope that may assist others. Cross the fingers. I can say reinstalling 18G95 did not change anything in my experience.

09-26-2019, 08:13 PM	#7
tommiy Member Join Date: Mar 2018 Posts: 92	With NightShift turned off I have had 2 days without High CPU issues on WindowServer process (and subequently the 100% CPU utilisation by DisplayLink). Seems that Apple is correct and they have broken the NightShift process on 18G95. Server me right for installing the supplementary updates. No patch expected from Apple on Mojave. Catalina is a hope they may fix it.