1
phablet@ubuntu-phablet:~$ cat /proc/cpuinfo 
Processor   : ARMv7 Processor rev 3 (v7l)
processor   : 0
BogoMIPS    : 2072.57

Features    : swp half thumb fastmult vfp edsp thumbee neon vfpv3 tls vfpv4 idiva idivt 
CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x0
CPU part    : 0xc07
CPU revision    : 3

Hardware    : MT6582
Revision    : 0000
Serial      : 0000000000000000

as this is a quad core device I was kind of expecting more cores to show up here. Why don't they?

lscpu does show that it has 4 CPUs, I think it is showing core 0 is online and cores 1,2,3 are offline. What does that mean? How do I turn them on?

phablet@ubuntu-phablet:~$ lscpu
Architecture:          armv7l
Byte Order:            Little Endian
CPU(s):                4
On-line CPU(s) list:   0
Off-line CPU(s) list:  1-3
Thread(s) per core:    1
Core(s) per socket:    1
Socket(s):             1
CPU max MHz:           1300.0000
CPU min MHz:           598.0000

2 Answers 2

1

The kernel will offline cpus when they are not required to keep the power consumption low. When the load increases it will automatically put more CPUs online.

One can see how many CPUs are available and how many are online using:

getconf -a | grep NPROCESSORS _NPROCESSORS_CONF 4 _NPROCESSORS_ONLN 1

Above, 4 are available, and 1 is online.

-1

I don't know why it is only showing 1 cpu, maybe it is only showing active/running cores. But try the command lscpu, it will give you the cpu information.

2
  • 2
    This is really a comment not an answer...
    – Tim
    Apr 20, 2015 at 14:01
  • I will add the output to the question, thanks, it is quite revealing, but I don't understand the offline cores.
    – Alan Bell
    Apr 20, 2015 at 16:44

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