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Only 1 of 2 cores working

Posted: Mon Jul 29, 2019 6:34 pm
by Relative
Just noticed today that only one of the two cores on my wife's laptop (Toshiba A215) are running. inxi indicates this is a Single Core model but sensors detect temps on both cores. htop shows only one core running.

sensors
k8temp-pci-00c3
Adapter: PCI adapter
Core0 Temp: +52.0°C
Core0 Temp: +52.0°C
Core1 Temp: +47.0°C
Core1 Temp: +48.0°C

System: Host: betty-Satellite-A215 Kernel: 5.0.0-20-generic x86_64 bits: 64 Desktop: MATE 1.20.1
Distro: Linux Mint 19.1 Tessa

Machine: Type: Laptop System: TOSHIBA product: Satellite A215 v: PSAFGU-020002 serial: <root required>
Mobo: ATI model: SB600 v: Rev 1 serial: <root required> BIOS: Phoenix v: 2.00 date: 01/25/2010

CPU: Topology: Single Core model: AMD Turion 64 X2 Mobile TL-58 bits: 64 type: UP L2 cache: 512 KiB
Speed: 1900 MHz min/max: 800/1900 MHz Core speed (MHz): 1: 1900

The CPU is correct but calling it a 'Single Core model' is not correct.

Dual-booted to Win 7 and it detects 2 cores. Ran Toshiba diagnostics and no failures were indicated.

Thought maybe a recent kernel update created the problem.

Booted 4 different kernels thinking that might be the problem but got the same results:
5.0.0-20
4.18.0-25
4.15.0-55
4.15.0-20

Not sure when this first started but I have no idea where to look for resolution.

Mike

Re: Only 1 of 2 cores working

Posted: Mon Jul 29, 2019 6:45 pm
by Relative
Update: Just booted from the flash drive I used for the original installation and inxi recognizes the two cores.

Like I said previously, I don't know when this changed, but it looks like software and not a hardware problem.

Help!
Mike

Re: Only 1 of 2 cores working

Posted: Mon Jul 29, 2019 7:23 pm
by athi
CPU: Topology: Single Core model: AMD Turion 64 X2 Mobile TL-58 bits: 64 type: UP L2 cache: 512 KiB
That is a dual core processor. Maybe 1 core is disabled until needed for power saving? Please check in BIOS and confirms that multicore support is enabled.

Re: Only 1 of 2 cores working

Posted: Mon Jul 29, 2019 7:29 pm
by Relative
No such option available in BIOS. Also, note that everything works in Win 7 and in Flash boot of original 19.1 configuration.

Mike

Re: Only 1 of 2 cores working

Posted: Mon Jul 29, 2019 8:09 pm
by athi
You can run nproc in Terminal and see how many cores that detects. Could be a CPU topology reporting error with inxi?

Maybe one of the developers will see this and have inputs. This is definitely over my head.

Re: Only 1 of 2 cores working

Posted: Mon Jul 29, 2019 8:28 pm
by Relative
nproc
1

That's it.
Not just a inxi problem. I have an application that always runs when I or my wife are not physically using the machines. It really cranks 100% on each and every core constantly. That's how I noticed that this particular laptop was just getting half done of what it should be doing - crunching one thread instead of two.

One other piece of information - 5 laptops and a Raspberry pi running this same application and all 5 are current on 19.1, and only the AMD one is not using all the cores. Seems like something more associated with AMD than Intel or ARM processors - The pi is running current level Raspbian and all 4 cores are cranking.

Mike

Re: Only 1 of 2 cores working

Posted: Mon Jul 29, 2019 10:21 pm
by athi
No idea, strange part is live session do 2 cores but installed shows 1 core.

Re: Only 1 of 2 cores working

Posted: Mon Jul 29, 2019 10:37 pm
by Relative
I should point out that 19.1 has been running since released with no problems. This is recent. As if one of the recent 'updates' caused the problem. Generally, I keep everything current.

Unfortunately, I just ran Timeshift using a new 256G flash drive and I discovered this problem the next day. Cannot restore using Timeshift.

Mike

Re: Only 1 of 2 cores working

Posted: Tue Jul 30, 2019 8:37 pm
by Relative
OK. Did a no-format re-install of 19.1 after selecting boot with 4.15.0-20 and removing all other kernels; and then brought it up to date with everything except for installing newer kernels. Worked fine with 2 cores. Then installed kernel 4.15.0-55 and still have 2 cores operating as they should.

Only a wild guess, but probably something was installed with the 4.18 and/or 5.0 kernels that caused this problem .

Note that earlier in this string I said I had tried 4.15.0-55 and 4.15.0-20 and they still showed 1 core. Now 4.15.0-20 and 4.15.0-55 work fine.

Evidently, selecting an older kernel from the Advanced menu doesn't get you ONLY the setup that went with that kernel. I suppose I could step up through the kernel releases until the failure re-occurs, but .....

Will create a fresh Timeshift as a checkpoint.

Mike

Re: Only 1 of 2 cores working

Posted: Wed Jul 31, 2019 3:49 am
by AndyMH
With old hardware there is very little point in using later kernels. I have had problems where something worked flawlessly under LM18.3 (4.4 kernel) but gave problems in LM19.0 (4.15 kernel). Installing 4.4 in LM19.0 fixed the problem (it was a monitor issue).

Re: Only 1 of 2 cores working

Posted: Wed Jul 31, 2019 11:11 pm
by Relative
This statement that I made in my previous comment still bothers me:

"Evidently, selecting an older kernel from the Advanced menu doesn't get you ONLY the setup that went with that kernel."

There must be other files that are updated over older kernel versions somewhere and selecting an older kernel gets those newer files instead of the ones that were original to that older kernel. ?????

Otherwise, it seems my attempt to boot an older kernel under the Advanced menu should have worked......or am I absolutely wrong?

Mike