SparkyLinux Forums

Software & hardware support => Newbie questions => Topic started by: GaryB on May 28, 2015, 06:15:38 PM

Title: How to enable multicore?
Post by: GaryB on May 28, 2015, 06:15:38 PM
I have a 4 core AMD but lscpu shows only one. how would I fix this?

Thanks
Gary
Title: Re: How to enable multicore?
Post by: pavroo on May 28, 2015, 06:27:36 PM
It happens if you installed 32 bit Sparky on multicore machine.
Run Sparky APTus -> Refresh package list, then Install tab -> Install 686-pae kernel.
Then reboot.
Title: Re: How to enable multicore?
Post by: Lizbeth on May 28, 2015, 11:42:19 PM
Just curious, if one installed the 32 bit system, couldn't one then install the 64bit kernel and headers also and run from them?
Title: Re: How to enable multicore?
Post by: pavroo on May 28, 2015, 11:46:52 PM
No, you can't.
I should be 32 bit (686-pae) kernel to handle multicore CPU and RAM bigger than 4 GB.

p.s.
It's possible but makes to many problems, I don't recommend it.
Title: Re: How to enable multicore?
Post by: GaryB on May 29, 2015, 08:49:06 PM
When I do that I get the message

You are running 64 bit system!

then exits.

Thanks
Title: Re: How to enable multicore?
Post by: GaryB on May 29, 2015, 09:22:55 PM
I went into my BIOS and made sure the cores were activated at boot, the boot mobo splash screen says 4 cores activated. I then booted up Kubuntu and lscpu says the same thing, 1 core.
Title: Re: How to enable multicore?
Post by: pavroo on May 29, 2015, 09:25:56 PM
Are you sure you are running 64 bit system?
Check it out:
uname -a
Title: Re: How to enable multicore?
Post by: GaryB on May 30, 2015, 01:20:22 PM
uname -a returns this:

Linux debian 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt9-3 (2015-04-23) x86_64 GNU/Linux
Title: Re: How to enable multicore?
Post by: pavroo on May 30, 2015, 05:08:04 PM
It looks like you have installed 64 bit system.
The big question is: does your CPU support multicore?
Can you check the CPU's maker specification?
Title: Re: How to enable multicore?
Post by: Wombat on May 31, 2015, 12:37:53 AM
Showing up as single core may be the result of just not properly recognising the CPU by whatever the method linux uses ...the same
when  HWINFO encounters an unknown item and displays a wrong default result in windows...

Title: Re: How to enable multicore?
Post by: pavroo on May 31, 2015, 12:14:14 PM
Show us:
nproc
Count the number of "physical processor(s)"
grep "physical id" /proc/cpuinfo | sort -u | wc -l
Count the number of "physical cores per CPU"
grep "cpu cores" /proc/cpuinfo |sort -u |cut -d":" -f2
Count the number of "logical cores " (including multi-threading cores)
grep -c "processor" /proc/cpuinfo
Title: Re: How to enable multicore?
Post by: MoroS on June 01, 2015, 02:23:50 PM
You could post the contents of /proc/cmdline file. You just might be running with the "acpi=off" option, which tends to disable additional cores.
Title: Re: How to enable multicore?
Post by: GaryB on June 01, 2015, 03:24:53 PM
garyb@debian:~$ nproc
1
garyb@debian:~$ grep "physical id" /proc/cpuinfo | sort -u | wc -l
1
garyb@debian:~$ grep "cpu cores" /proc/cpuinfo |sort -u |cut -d":" -f2
1
garyb@debian:~$ grep -c "processor" /proc/cpuinfo
1
garyb@debian:~$
Title: Re: How to enable multicore?
Post by: GaryB on June 01, 2015, 03:26:21 PM
/proc/cmdline

BOOT_IMAGE=/boot/vmlinuz-3.16.0-4-amd64 root=UUID=cc17d4be-6875-4daa-965f-329ca3d66049 ro nolapic splash
Title: Re: How to enable multicore?
Post by: MoroS on June 01, 2015, 03:43:28 PM
Quote from: GaryB on June 01, 2015, 03:26:21 PM
/proc/cmdline

BOOT_IMAGE=/boot/vmlinuz-3.16.0-4-amd64 root=UUID=cc17d4be-6875-4daa-965f-329ca3d66049 ro nolapic splash

Well, it's not "acpi=off", but still, the result's similar. The LAPIC is a Local Advanced Programmable Interrupt Controler. It basically handles interrupts and multi-core functionality. Having the "nolapic" option enabled you basically limit yourself to a single core/CPU. Many people use it to bypass problems with their system hanging at boot (mostly due to Kernel Mode Setting problems, which can be a pain... :/ ).

Here's what you can do to test it out. When booting, in GRUB, before choosing an option to boot (or letting GRUB do that for you after the 5 seconds timeout), select the option you want to boot (most probably the first on the list) and press the "e" key. Find the line that ends with "ro nolapic splash" (you'll probably need to scroll a bit) and remove the "nolapic" part. After that press F10 to boot the edited config. If the system boots without problems, check if you have all your cores visible and active. If so, then we'll make this setup permanent in the next posts (don't have my Sparky environment with me right now and I don't want to advise on such things out of my head - too risky ;) ).
Title: Re: How to enable multicore?
Post by: GaryB on June 01, 2015, 04:53:01 PM
I had to put the nolapic command in to overcome boot freezing, I had no idea that it was disabling my extra cores, so I replaced nolapic with "noapic pci=assign-busses apicmaintimer idle=poll reboot=cold,hard". I now have 4 cores running.

Thanks everybody for your help.

I'm so happy to have found Sparky Linux.
Title: Re: How to enable multicore?
Post by: MoroS on June 01, 2015, 05:50:58 PM
Those boot freezes are probably KMS-related. What helped me with that god-damned-kms-bull**it (sorry, just too much emotions when thinking about how many hardware platforms I had, that worked flawlessly with KMS... 0 out of 5... :'( ), was a kernel exchange. I've dumped the Debian kernel in favour of Liquorix. You might want to try this. I've been running without any freezes (and without any additional kernel parameters) for almost half a year now. ;) You might also try removing those parameters when Debian's 4.0 kernel hits Testing.
Title: Re: How to enable multicore?
Post by: GaryB on June 02, 2015, 12:13:01 AM
What is the Liqouix kernal, there are NON_PAE, PAE, & 64?
Title: Re: How to enable multicore?
Post by: pavroo on June 02, 2015, 12:25:55 AM
Non-PAE and PAE are to 32 bit systems only.
Non-PAE supports 1 core CPU and RAM memory up to 4 GB.
PAE supports more.

64 bit kernel is... for 64 bit systems.
Title: Re: How to enable multicore?
Post by: GaryB on June 02, 2015, 12:44:22 AM
If it causes problems how would I go back?
Title: Re: How to enable multicore?
Post by: pavroo on June 02, 2015, 12:48:35 AM
If you will install Liquorix kernel, it be available via Grub list on boot start list.
If any problem, reboot and boot your system using older kernel still available on the list.
Title: Re: How to enable multicore?
Post by: way12go on June 02, 2015, 04:49:02 AM
Quote from: GaryB on June 02, 2015, 12:13:01 AM
What is the Liqouix kernal, there are NON_PAE, PAE, & 64?

http://sparkylinux.org/forum/index.php/topic,3009.msg5806.html#msg5806
Title: Re: How to enable multicore?
Post by: GaryB on June 03, 2015, 12:08:19 AM
I added the Liqouix kernal, what command would I issue to see what kernal I'm running? Does the Sparky Linux Game Over use this kernal or must it be added?
Title: Re: How to enable multicore?
Post by: pavroo on June 03, 2015, 12:57:58 PM
All sparky spins use Debian's kernel as default.
If you'd like to use Liquorix kernel you have to install it whatever sparky edition you have.

To check it out, run:
uname -a
or Sparky About tool if you have it installed.