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How does one interpret the information printed out by the following command in Linux

cat /proc/cpuinfo

On my laptop, I get the following output:

[gaurish108:~]$ cat /proc/cpuinfo                                                                                                      (02-09 15:34)
processor   : 0
vendor_id   : GenuineIntel
cpu family  : 6
model       : 37
model name  : Intel(R) Core(TM) i3 CPU       M 330  @ 2.13GHz
stepping    : 2
cpu MHz     : 933.000
cache size  : 3072 KB
physical id : 0
siblings    : 4
core id     : 0
cpu cores   : 2
apicid      : 0
initial apicid  : 0
fdiv_bug    : no
hlt_bug     : no
f00f_bug    : no
coma_bug    : no
fpu     : yes
fpu_exception   : yes
cpuid level : 11
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 rdtscp lm constant_tsc arch_perfmon pebs bts xtopology nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 popcnt lahf_lm arat dts tpr_shadow vnmi flexpriority ept vpid
bogomips    : 4256.49
clflush size    : 64
cache_alignment : 64
address sizes   : 36 bits physical, 48 bits virtual
power management:

processor   : 1
vendor_id   : GenuineIntel
cpu family  : 6
model       : 37
model name  : Intel(R) Core(TM) i3 CPU       M 330  @ 2.13GHz
stepping    : 2
cpu MHz     : 933.000
cache size  : 3072 KB
physical id : 0
siblings    : 4
core id     : 0
cpu cores   : 2
apicid      : 1
initial apicid  : 1
fdiv_bug    : no
hlt_bug     : no
f00f_bug    : no
coma_bug    : no
fpu     : yes
fpu_exception   : yes
cpuid level : 11
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 rdtscp lm constant_tsc arch_perfmon pebs bts xtopology nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 popcnt lahf_lm arat dts tpr_shadow vnmi flexpriority ept vpid
bogomips    : 4256.40
clflush size    : 64
cache_alignment : 64
address sizes   : 36 bits physical, 48 bits virtual
power management:

processor   : 2
vendor_id   : GenuineIntel
cpu family  : 6
model       : 37
model name  : Intel(R) Core(TM) i3 CPU       M 330  @ 2.13GHz
stepping    : 2
cpu MHz     : 933.000
cache size  : 3072 KB
physical id : 0
siblings    : 4
core id     : 2
cpu cores   : 2
apicid      : 4
initial apicid  : 4
fdiv_bug    : no
hlt_bug     : no
f00f_bug    : no
coma_bug    : no
fpu     : yes
fpu_exception   : yes
cpuid level : 11
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 rdtscp lm constant_tsc arch_perfmon pebs bts xtopology nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 popcnt lahf_lm arat dts tpr_shadow vnmi flexpriority ept vpid
bogomips    : 4256.43
clflush size    : 64
cache_alignment : 64
address sizes   : 36 bits physical, 48 bits virtual
power management:

processor   : 3
vendor_id   : GenuineIntel
cpu family  : 6
model       : 37
model name  : Intel(R) Core(TM) i3 CPU       M 330  @ 2.13GHz
stepping    : 2
cpu MHz     : 933.000
cache size  : 3072 KB
physical id : 0
siblings    : 4
core id     : 2
cpu cores   : 2
apicid      : 5
initial apicid  : 5
fdiv_bug    : no
hlt_bug     : no
f00f_bug    : no
coma_bug    : no
fpu     : yes
fpu_exception   : yes
cpuid level : 11
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 rdtscp lm constant_tsc arch_perfmon pebs bts xtopology nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 popcnt lahf_lm arat dts tpr_shadow vnmi flexpriority ept vpid
bogomips    : 4256.42
clflush size    : 64
cache_alignment : 64
address sizes   : 36 bits physical, 48 bits virtual
power management:

Now it says that there are 4 processors on the system. There is also a field inside the information of each processor field which says cou cores are 2.

Does that mean there are 4 Intel i3's CPU's on my system? What does the processor field really mean here?

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3 Answers 3

Reset to default
17

The entries are logical processors; objects used by the kernel internally, not necessarily tied to physical devices. (Note that they all have the same physical id.)

In other words, they represent the four cores of a single Intel i3 CPU.

Also, as noted on this post (which is not exactly a duplicate but closely related), those cores are logical as well – the CPU has two cores physically but supports hyperthreading.

Note that some Intel processors (the i5 included) use hyperthreading, a system where a single processor has (for example) 2 pyhsical cores, but will provide 4 logical cores - allowing the operating system to treat the processor as having more cores than it really does.

If your system has the lscpu tool (part of recent util-linux), it would output a more human-readable summary of the CPUs installed, for example:

Thread(s) per core:    2
Core(s) per socket:    2
Socket(s):             1
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3
  • Is the physical address size the longer the better, or the shorter the better?
    – Qian Chen
    Jun 16, 2015 at 8:10
  • @ElgsQianChen: Usually, the longer the better. See how the world moved from 8-bit CPUs to 16-bit to 32-bit and then to 64-bit CPUs. That bit count is the "address size".
    – u1686_grawity
    Jun 16, 2015 at 8:15
  • Seems I see a variety of physical sizes, like 36 bits, 40 bits, and 46 bits. The virtual size seems to be always 48 bits. So why there are different physical sizes, and what do they mean when they are shorter or longer?
    – Qian Chen
    Jun 16, 2015 at 8:32
10

Here is an inline awk script to pretty-print and extract relevant data from /proc/cpuinfo :

cat /proc/cpuinfo | \
awk -v FS=':' '                                       \
  /^physical id/ { if(nb_cpu<$2)  { nb_cpu=$2 } }     \
  /^cpu cores/   { if(nb_cores<$2){ nb_cores=$2 } }   \
  /^processor/   { if(nb_units<$2){ nb_units=$2 } }   \
  /^model name/  { model=$2 }                         \
                                                      \
  END{                                                \
   nb_cpu=(nb_cpu+1);                                 \
   nb_units=(nb_units+1);                             \
                                                      \
   print "CPU model:",model;                          \
   print nb_cpu,"CPU,",nb_cores,"physical cores per CPU, total",nb_units,"logical CPU units" \
 }'

Output for a high-performance server:

CPU model:  Intel(R) Xeon(R) CPU           X5650  @ 2.67GHz
2 CPU,  6 physical cores per CPU, total 24 logical CPU units

Output for a Core i5 laptop:

CPU model:  Intel(R) Core(TM) i5-2520M CPU @ 2.50GHz
1 CPU,  2 physical cores per CPU, total 4 logical CPU units
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0

It simply means :

  1. You actually have one quad-core i3 CPU on your system.

  2. This "one quad-core i3 CPU" has four logical cores in it.

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1
  • 3
    Actually, it's a dual-core i3 CPU with four logical cores.
    – David Schwartz
    Feb 14, 2012 at 10:40

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