# [SOLVED]Second CPU not working!!

## dritan

hi all,

i just bought a new Dell Inspiron 640M, its definitely the best pc i have used by far, but i have some problem with cpu...on gnome sys monitor the second cpu is always at 0

here is how it looks like...i configured the laptop from this guide, including the power management parts...how come this is happening? i want both cpus to be used when on heavy load!! help

 thanks!!

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## PaulBredbury

 *dritan wrote:*   

> i want both cpus to be used when on heavy load

 

So do I, but there's no magical way to do it. If the program uses only a single thread, then it won't use the second CPU.

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## dritan

yea i know that...but mine is ALWAYS at 0, while on the X2 on my desktop they both work even when its idle...

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## sonicbhoc

did you enable smp support in your kernel? what does

```
cat /proc/cpuinfo
```

return? If you run an emerge with a MAKEOPTS="-j3" does it use both cores? It does on mine...

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## dritan

yes i am pretty sure i have SMP support on...cpuinfo says this

```
dritan@Dell640m ~ $ cat /proc/cpuinfo 

processor       : 0

vendor_id       : GenuineIntel

cpu family      : 6

model           : 15

model name      : Intel(R) Core(TM)2 CPU         T7200  @ 2.00GHz

stepping        : 6

cpu MHz         : 2000.000

cache size      : 4096 KB

physical id     : 0

siblings        : 2

core id         : 0

cpu cores       : 2

fdiv_bug        : no

hlt_bug         : no

f00f_bug        : no

coma_bug        : no

fpu             : yes

fpu_exception   : yes

cpuid level     : 10

wp              : yes

flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm

bogomips        : 3993.49

clflush size    : 64

processor       : 1

vendor_id       : GenuineIntel

cpu family      : 6

model           : 15

model name      : Intel(R) Core(TM)2 CPU         T7200  @ 2.00GHz

stepping        : 6

cpu MHz         : 2000.000

cache size      : 4096 KB

physical id     : 0

siblings        : 2

core id         : 1

cpu cores       : 2

fdiv_bug        : no

hlt_bug         : no

f00f_bug        : no

coma_bug        : no

fpu             : yes

fpu_exception   : yes

cpuid level     : 10

wp              : yes

flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm

bogomips        : 3990.08

clflush size    : 64

```

and i dont know how to check if it uses both processors, i have -j3 in make.conf and that screenshot that i posted was when i was compiling something but CPU1 was 100% while CPU2 was 0%...

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## dritan

update:

poking around the settings i found something interesting...

```
Dell640m dritan # cat /sys/devices/system/cpu/cpu1/online 

1

Dell640m dritan # cat /sys/devices/system/cpu/cpu0/online 

cat: /sys/devices/system/cpu/cpu0/online: No such file or directory

```

CPU1 has an online flag set and its 1, while in CPU0, this flag does not exist, when i tried to manually add it, i got permission errors despite running from root, so i guess it has something to do with system bus or kernel which auto detects the cpus, could this be the problem? any ways to work around this?

thanks in adv

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## dritan

update2:

after some googling, i found out that CPU0 cannot be offline because of obvious reasons, and now i am stuck! could it be that my kernel does not recognize it? i am using the masked suspend2-sources-2.6.20, anyone else has this problem with this kernel?

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## dritan

Fixed:

changed to gentoo-sources-2.6.20 and changed some misc settings in kernel and now both CPUs work when compiling!! seems like suspend2 was masked for a reason...

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## Small_Penguin

Solved in suspend-2.2.9.13 (affected versions: 2.2.9.11, 2.2.9.12).

You might want to try it again, it works great now!

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