Dual core only using one core

[JohnKS]

Hi: I'm running Mint 8 x64 in KDE. I have an AMD X2 dual core CPU. When I run System Monitor only one core shows up under CPU history. I couldn't seem to find another post that asks about this. Has anyone run into this before? Is it a problem with System Monitor or have I failed to configure something properly? Glad for any insight. Thanks. John

[Aging Technogeek]

Check the info center in the System menu. There is an entry for processor information. It shows my core 2 duo as cpu#0 and cpu #1

You can also install "hardinfo" from Package Manager. It will show up in your Menu under System as System Profiler and Benchmark. This will give you another means to check your system. Select Processor and you should see two entries for your two cores.

[JohnKS]

Hi: thanks for your reply. From Info Centre I get the correct identification of the processor (AMD X2 64bit dual core 5200+), but it is labelled #0 - there is no #1 listed which, from what you mentioned, would show both cores being recognised, or used by the OS. This is what led me to question whether both cores are being recognised.

I checked "hardinfo" - the generated report is shown below. Not quite sure how to interpret all of it. The processor is identified but I'm not sure if it's pointing to both cores.
Thank you for your help. John

-Processor-
Name : AMD Athlon(tm) 64 X2 Dual Core Processor 5200+
Family, model, stepping : 15, 67, 2 (AMD Opteron/Athlon64/FX)
Vendor : AuthenticAMD
-Configuration-
Cache Size : 1024kb
Frequency : 2611.88MHz
BogoMIPS : 5223.76
Byte Order : Little Endian
-Features-
FDIV Bug : no
HLT Bug : no
F00F Bug : no
Coma Bug : no
Has FPU : yes
-Cache-
Level 1 (Data) : 2-way set-associative, 512 sets, 64KB size
Level 1 (Instruction) : 2-way set-associative, 512 sets, 64KB size
Level 2 (Unified) : 16-way set-associative, 1024 sets, 1024KB size
-Capabilities-
fpu : Floating Point Unit
vme : Virtual 86 Mode Extension
de : Debug Extensions - I/O breakpoints
pse : Page Size Extensions (4MB pages)
tsc : Time Stamp Counter and RDTSC instruction
msr : Model Specific Registers
pae : Physical Address Extensions
mce : Machine Check Architeture
cx8 : CMPXCHG8 instruction
apic : Advanced Programmable Interrupt Controller
sep : Fast System Call (SYSENTER/SYSEXIT)
mtrr : Memory Type Range Registers
pge : Page Global Enable
mca : Machine Check Architecture
cmov : Conditional Move instruction
pat : Page Attribute Table
pse36 : 36bit Page Size Extensions
clflush : Cache Line Flush instruction
mmx : MMX technology
fxsr : FXSAVE and FXRSTOR instructions
sse : SSE instructions
sse2 : SSE2 (WNI) instructions
ht : HyperThreading
syscall : SYSCALL and SYSEXIT instructions
nx : No-execute Page Protection
mmxext : Extended MMX Technology
fxsr_opt
rdtscp : RDTSCP
lm : LAHF/SAHF in long mode
3dnowext : Extended 3DNow! Technology
3dnow : 3DNow! Technology
up : smp kernel running on up
rep_good : rep microcode works well on this CPU
extd_apicid
pni : Streaming SIMD Extension 3 (Prescott New Instruction)
cx16 : CMPXCHG16B instruction
lahf_lm : LAHF/SAHF in long mode
cmp_legacy : HyperThreading not valid
svm : Virtualization support (AMD)
extapic
cr8_legacy

[Biker]

Hi: I'm running Mint 8 x64 in KDE. I have an AMD X2 dual core CPU. When I run System Monitor only one core shows up under CPU history. I couldn't seem to find another post that asks about this. Has anyone run into this before? Is it a problem with System Monitor or have I failed to configure something properly? Glad for any insight. Thanks. John

If you want to see if both cores are being utilized, open a terminal and type: top

When you get the information on the screen, press 1. At the top, you should then see both cores listed and how much they're being tasked with the processes on your system. Should look something like this.

topshot.png

[JohnKS]

Thanks for your reply and advice. Here's what I got:

top - 11:17:50 up 2:34, 1 user, load average: 0.03, 0.11, 0.13
Tasks: 145 total, 1 running, 144 sleeping, 0 stopped, 0 zombie
Cpu(s): 2.3%us, 0.7%sy, 0.0%ni, 95.3%id, 1.7%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 4058860k total, 1677316k used, 2381544k free, 21780k buffers
Swap: 9936160k total, 0k used, 9936160k free, 1068080k cached

It seems to me only one core is being used. Could there be a bios setting issue? On my MSI motherboard, there is no option to use anythingother both cores. Best. John

[Biker]

You pressed "1" once top was running, yes?

[JohnKS]

I did.

top - 11:32:19 up 2:49, 1 user, load average: 0.16, 0.12, 0.09
Tasks: 145 total, 2 running, 143 sleeping, 0 stopped, 0 zombie
Cpu0 : 5.1%us, 2.2%sy, 0.0%ni, 91.8%id, 0.8%wa, 0.1%hi, 0.0%si, 0.0%st
Mem: 4058860k total, 1675712k used, 2383148k free, 23192k buffers
Swap: 9936160k total, 0k used, 9936160k free, 1068628k cached

[Biker]

OK. That's just.... weird. I've never seen an installation ignore a CPU core before.

Is this a "base" installation? Or have you modified it with extra software, updates, etc.?

[kwisher]

Create a Mint-8 Gnome live disc and boot to that. Run the apps mentioned previously to see if it is a OS error.

[JohnKS]

I installed normally. Everything was fine and in fact, the system even now does run pretty well. I did the usual updates using synaptic package manager - nothing abnormal as far as I can tell. I did Google the issue and found that a couple of years ago, some people with Ubuntu installations were losing a core. The thought was that it might be tied to Grub in some way, or perhaps the kernel but from my brief reading, there did not seem to be an identified cause or cure. One poster (back then) did mention something about removing "nolacpi" (do I have that right?) which solved things, but others found that it didn't. At any rate, that sort of procedure takes me beyond my knowledge.

Well, I sure appreciate your working with me on this even though it's a puzzle. If you have further insight I'll give anything a try as I really do love Mint. John

[JohnKS]

Hi: I ran both the Gnome and KDE live discs and repeated the tests from within the live system. Same result.

[Biker]

Not sure how grub could contribute to the issue as it's nothing more than a boot loader. Unless there's an option being passed during the boot process that causes the system to recognize just one core.

Working on a bit of a system issue myself right now and as soon as I can get Mint to play nicely with my notebook again, I'll dig into it further.

(**grumbles** Should have just left things alone.. But NOOOOOOOO! Had to wipe the drive and reload everything to better utilize the available space.. **banging head on desk**)

[JohnKS]

Out of curiosity, I went into System Settings - Power Management. My system is set to performance. If I go to Edit Profile|CPU and System, there is an option to turn off CPU(s). It shows only CPU(0) which is what I've been experiencing. Is there some odd potential link between Power Management and core recognition? Could there be a configuration file that has told the system (somehow) that one core should be disabled? OK, I'm reaching here.

[Biker]

Possible... You could try to boot with a noacpi option and see if that works.

[JohnKS]

Biker, Can you tell me how I do that? Thanks.

[Biker]

When your Grub menu comes up, arrow to the entry you wish to select and press "E". This puts you into "edit" mode.

Scroll down to the line that looks similar to this:

linux /boot/vmlinuz-2.6.31-16-generic root=UUID=19b8a6dd-7416-4ac7-b22b-63869cba38ac ro quiet splash

At the end of that line, type in "noacpi" then press Ctrl-X to execute and start the boot process.

[JohnKS]

Hi Biker: I did that and also turned off ACPI in the bios. I'm afraid it didn't work. Still one core. Thanks for trying. John

[JohnKS]

Another thought. Is it possible for a CPU to lose a core because it has failed or would that cause the entire CPU to fail?

[Biker]

I honestly don't know if a core failure would cause the entire CPU to fail or not.

[JohnKS]

I checked the cores and they are OK. I also replaced the CPU with an identical one of make and type but slightly lower speed and this one only registers one core only also. I'm at a loss. Would a reinstall of Mint make sense?