Kernel Version 3.3.4-5.fc17.x86_64

CPU info:

sashan@dhcp-au-122 ~  $ cat /proc/cpuinfo 
processor   : 0
vendor_id   : GenuineIntel
cpu family  : 6
model       : 42
model name  : Intel(R) Core(TM) i7-2640M CPU @ 2.80GHz
stepping    : 7
microcode   : 0x28
cpu MHz     : 2793.577
cache size  : 4096 KB
physical id : 0
siblings    : 1
core id     : 0
cpu cores   : 1
apicid      : 0
initial apicid  : 0
fpu     : yes
fpu_exception   : yes
cpuid level : 13
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 syscall nx rdtscp lm constant_tsc up arch_perfmon pebs bts nopl xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx lahf_lm ida arat epb xsaveopt pln pts dts tpr_shadow vnmi flexpriority ept vpid
bogomips    : 5587.15
clflush size    : 64
cache_alignment : 64
address sizes   : 36 bits physical, 48 bits virtual
power management:

Notice that it says 1 core and that it is an i7 which has 2 (http://ark.intel.com/products/53464/Intel-Core-i7-2640M-Processor-4M-Cache-up-to-3_50-GHz)

2 Answers 2


In order to use multiple cores, the kernel needs to be compiled with SMP support. The Fedora kernel should already have it. You can verify with the following:

zcat /proc/config.gz | grep 'CONFIG_SMP'

From the help text for kernel configuration:

This enables support for systems with more than one CPU. If you say N here, the kernel will run on single and multiprocessor machines, but will use only one CPU of a multiprocessor machine. If you say Y here, the kernel will run on many, but not all, single processor machines. On a single processor machine, the kernel will run faster if you say N here.

  • SMP suppoprt has been in Fedora kernels for ages, certainly from before this one.
    – vonbrand
    Jan 24, 2013 at 17:44
  • @vonbrand I am aware. I probably could have deleted this answer.
    – jordanm
    Jan 24, 2013 at 17:50

My grub boot config had acpi=off in the kernel boot parameter list. Changed this to acpi=on. I originally had to turn acpi off when using the live cd to install this version of Linux because it wouldn't boot on this laptop from the default live cd kernel boot parameter list.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .