The number of processors and cores in my systems

Question

This is the output of cat /proc/cpuinfo

processor   : 0
vendor_id   : GenuineIntel
cpu family  : 6
model       : 78
model name  : Intel(R) Core(TM) i5-6200U CPU @ 2.30GHz
stepping    : 3
microcode   : 0x74
cpu MHz     : 2400.000
cache size  : 3072 KB
physical id : 0
siblings    : 4
core id     : 0
cpu cores   : 2
apicid      : 0
initial apicid  : 0
fpu     : yes
fpu_exception   : yes
cpuid level : 22
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 pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf tsc_known_freq pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb invpcid_single pti retpoline intel_pt rsb_ctxsw tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid mpx rdseed adx smap clflushopt xsaveopt xsavec xgetbv1 xsaves dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp
bugs        : cpu_meltdown spectre_v1 spectre_v2
bogomips    : 4800.00
clflush size    : 64
cache_alignment : 64
address sizes   : 39 bits physical, 48 bits virtual
power management:

processor   : 1
vendor_id   : GenuineIntel
cpu family  : 6
model       : 78
model name  : Intel(R) Core(TM) i5-6200U CPU @ 2.30GHz
stepping    : 3
microcode   : 0x74
cpu MHz     : 2400.000
cache size  : 3072 KB
physical id : 0
siblings    : 4
core id     : 1
cpu cores   : 2
apicid      : 2
initial apicid  : 2
fpu     : yes
fpu_exception   : yes
cpuid level : 22
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 pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf tsc_known_freq pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb invpcid_single pti retpoline intel_pt rsb_ctxsw tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid mpx rdseed adx smap clflushopt xsaveopt xsavec xgetbv1 xsaves dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp
bugs        : cpu_meltdown spectre_v1 spectre_v2
bogomips    : 4800.00
clflush size    : 64
cache_alignment : 64
address sizes   : 39 bits physical, 48 bits virtual
power management:

processor   : 2
vendor_id   : GenuineIntel
cpu family  : 6
model       : 78
model name  : Intel(R) Core(TM) i5-6200U CPU @ 2.30GHz
stepping    : 3
microcode   : 0x74
cpu MHz     : 2400.000
cache size  : 3072 KB
physical id : 0
siblings    : 4
core id     : 0
cpu cores   : 2
apicid      : 1
initial apicid  : 1
fpu     : yes
fpu_exception   : yes
cpuid level : 22
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 pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf tsc_known_freq pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb invpcid_single pti retpoline intel_pt rsb_ctxsw tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid mpx rdseed adx smap clflushopt xsaveopt xsavec xgetbv1 xsaves dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp
bugs        : cpu_meltdown spectre_v1 spectre_v2
bogomips    : 4800.00
clflush size    : 64
cache_alignment : 64
address sizes   : 39 bits physical, 48 bits virtual
power management:

processor   : 3
vendor_id   : GenuineIntel
cpu family  : 6
model       : 78
model name  : Intel(R) Core(TM) i5-6200U CPU @ 2.30GHz
stepping    : 3
microcode   : 0x74
cpu MHz     : 2400.000
cache size  : 3072 KB
physical id : 0
siblings    : 4
core id     : 1
cpu cores   : 2
apicid      : 3
initial apicid  : 3
fpu     : yes
fpu_exception   : yes
cpuid level : 22
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 pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf tsc_known_freq pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb invpcid_single pti retpoline intel_pt rsb_ctxsw tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid mpx rdseed adx smap clflushopt xsaveopt xsavec xgetbv1 xsaves dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp
bugs        : cpu_meltdown spectre_v1 spectre_v2
bogomips    : 4800.00
clflush size    : 64
cache_alignment : 64
address sizes   : 39 bits physical, 48 bits virtual
power management:

Would I be right in assuming I have 4 processors that have 2 cores each? Why then, are the core id's in each processor numbered 1, 0, 1, 0 as seen from the output of cat /proc/cpuinfo | grep 'core id' ?

core id     : 0
core id     : 1
core id     : 0
core id     : 1

score 6 · Accepted Answer · edited Apr 30 '19 at 21:08

/proc/cpuinfo's information might be a bit confusing. These are kernel processors which are not necessarily physical processors. These include cores/modules and threads, too.

When you take a look at this:

physical id : 0
siblings    : 4
core id     : 0
cpu cores   : 2

physical id is the actual physical processor count. It remains always 0, meaning that you have 1 CPU in your system.

siblings designates that it is one of the 4 in total kernel processors (threads, if you like).

core id can be explained as the thread per core meaning you have 2 threads per each core, each with ids 0 and 1.

cpu cores is the total number of cores that this processor has.

Perhaps it would be easier to use lscpu - information is presented in a more straightforward way.

Kiwy · Answer 2 · 2018-03-29T12:44:57.183

1

Your cpu a i5-6200U have 2 cores and 4 threads.

Physical core are numbered 0 and 1 on the item core id.
Your virtual core (aka thread) are numbered from 0 to 3 on the item processor.
Finally your computer have one CPU numbered 0 on item physical id

edited Mar 29 '18 at 12:44

answered Mar 29 '18 at 12:21

Kiwy

9,534

score 0 · Answer 3 · answered Mar 29 '18 at 12:26

No, you only have one processor with 2 cores that supports 2 threads each. That also matches the information on Intel's page about i5-6200U. The numbering of "processors" in the contents of /proc/cpuinfo is a linux-thing, different processors would have different physical id.

The number of processors and cores in my systems

3 Answers3