4 núcleos faltando e alta carga após o upgrade de 14.10 para 16.04.1

Question

Eu recentemente atualizei meu Ubuntu Server de 14.10 para 16.04.1. Ele está rodando um Core i7 com HT que está claramente habilitado no BIOS (veja Fotos)

Noentanto,ohtopmostraapenas4núcleosvirtuais(antesdaatualizaçãoeram8),bemcomoumacargamédiadealgoacimade~4.Parecequealgoestáescondendo4núcleosvirtuaiseosusandoconstantemente.Aoexecutarohtopcomoroot,nãohánadaaservistoqueuse400%dacargadaCPU.

Como posso verificar o que está acontecendo e recuperar meus 4 núcleos?

Editar:

:~$ cat /proc/cpuinfo 
processor   : 0
vendor_id   : GenuineIntel
cpu family  : 6
model       : 30
model name  : Intel(R) Core(TM) i7 CPU         870  @ 2.93GHz
stepping    : 5
microcode   : 0x5
cpu MHz     : 2933.232
cache size  : 8192 KB
physical id : 0
siblings    : 4
core id     : 0
cpu cores   : 4
apicid      : 0
initial apicid  : 0
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 syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 popcnt lahf_lm tpr_shadow vnmi flexpriority ept vpid dtherm ida
bugs        :
bogomips    : 5866.46
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       : 30
model name  : Intel(R) Core(TM) i7 CPU         870  @ 2.93GHz
stepping    : 5
microcode   : 0x5
cpu MHz     : 2933.232
cache size  : 8192 KB
physical id : 0
siblings    : 4
core id     : 1
cpu cores   : 4
apicid      : 2
initial apicid  : 2
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 syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 popcnt lahf_lm tpr_shadow vnmi flexpriority ept vpid dtherm ida
bugs        :
bogomips    : 5866.46
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       : 30
model name  : Intel(R) Core(TM) i7 CPU         870  @ 2.93GHz
stepping    : 5
microcode   : 0x5
cpu MHz     : 2933.232
cache size  : 8192 KB
physical id : 0
siblings    : 4
core id     : 2
cpu cores   : 4
apicid      : 4
initial apicid  : 4
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 syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 popcnt lahf_lm tpr_shadow vnmi flexpriority ept vpid dtherm ida
bugs        :
bogomips    : 5866.46
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       : 30
model name  : Intel(R) Core(TM) i7 CPU         870  @ 2.93GHz
stepping    : 5
microcode   : 0x5
cpu MHz     : 2933.232
cache size  : 8192 KB
physical id : 0
siblings    : 4
core id     : 3
cpu cores   : 4
apicid      : 6
initial apicid  : 6
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 syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 popcnt lahf_lm tpr_shadow vnmi flexpriority ept vpid dtherm ida
bugs        :
bogomips    : 5866.46
clflush size    : 64
cache_alignment : 64
address sizes   : 36 bits physical, 48 bits virtual
power management:

    

Answer 1

A resposta foi ativar o acpi para o sistema operacional no BIOS. Há uma configuração para habilitar os sistemas operacionais compatíveis com ACPI. Eu desliguei antes da atualização para poder arrancar a partir de um USB Stick ao vivo e fazer um backup. Totalmente esqueci até ler a resposta de Chai T.Rex. Obrigado a todos!