Yesterday I installed the above referenced kernel on two Raspberry PIs, a 3B+ and a 3B. I also installed it on a BeagleBone Black and a Hummingboard2 (nxp i.mx6 Quad CPU).
On the BeagleBone Black and the Hummingboard, no problems at all, so this appears to be specific to the Raspberry PI platform or CPU. The Raspberry PI's are both actually running, but I noticed that top tells me that the load average is 4.0. But these things are not actually doing anything. Top does not show any process using more than 0.7% CPU and that it tells me that each core is nearly 100% idle. dmesg is not giving me any significant errors.
I have worked at finding the problem for a few hours and have not found a lot. But here is what I have found:
If I reboot to kernel 4.20.16, the problem goes away.
When booted into kernel 5.0.3 dmesg gives this line: [ 16.342693] systemd[1]: Mounting Kernel Debug File System...
but I see nothing that indicated why this might be happening.
Anyone else try kernel 5.0.3 on a Raspberry Pi? Any thoughts on where to look for the problem?
Thanks very much! Will
I have continued to to look into this and found something.
the vchiq driver seems to behave differently under kernel 5.0.3 than it did under 4.20.16. Under both kernels, running the ps command shows the 4 vchiq processes. They are:
vchiq-slot/0 vchiq-recy/0 vchiq-sync/0 vchiq-keep/0
For 4.20.16 the processes state code is S (interruptible sleep). On 5.0.3 they are all D (uninterruptible sleep).
Any thoughst on if these processes are what are causing the load on my Raspberry PIs to be 4.0 all the time or what to do about it would be greatly appreciated.
Thank you Will
Hi William,
William Jacobs wlj15238@yahoo.com hat am 27. März 2019 um 18:33 geschrieben:
I have continued to to look into this and found something.
the vchiq driver seems to behave differently under kernel 5.0.3 than it did under 4.20.16. Under both kernels, running the ps command shows the 4 vchiq processes. They are:
vchiq-slot/0 vchiq-recy/0 vchiq-sync/0 vchiq-keep/0
For 4.20.16 the processes state code is S (interruptible sleep). On 5.0.3 they are all D (uninterruptible sleep).
Any thoughst on if these processes are what are causing the load on my Raspberry PIs to be 4.0 all the time or what to do about it would be greatly appreciated.
this is a known, but more "cosmetic" issue. AFAIU this load has already been there, but hidden:
https://github.com/raspberrypi/linux/issues/2881
Thank you Will
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Stefan Wahren -
William Jacobs