Running cat /proc/cpuinfo reveals some information on the CPU, e.g.

   1. cat /proc/cpuinfo
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 15
model           : 4
model name      : Intel(R) Pentium(R) 4 CPU 3.00GHz
stepping        : 1
cpu MHz         : 2992.799
cache size      : 1024 KB
physical id     : 0
siblings        : 1
core id         : 0
cpu cores       : 1
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 5
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 constant_tsc up pni monitor ds_cpl cid xtpr
bogomips        : 5990.45

What is the meaning of this all?

Most info is taken from: Intel's developers guide

  cpu family 
  model name 
  cpu MHz  
  cache size 
  physical id 
  core id    
  cpu cores  
  cpuid level 
  • fpu - Floating Point Unit On-Chip. The processor contains an x87 FPU.

  • vme - Virtual 8086 Mode Enhancements. Virtual 8086 mode enhancements, including CR4.VME for controlling the feature, CR4.PVI for protected mode virtual interrupts, software interrupt indirection, expansion of the TSS with the software indirection bitmap, and EFLAGS.VIF and EFLAGS.VIP flags.

  • de - Debugging Extensions. Support for I/O breakpoints, including CR4.DE for controlling the feature, and optional trapping of accesses to DR4 and DR5.

  • pse - Page Size Extension. Large pages of size 4 MByte are supported, including CR4.PSE for controlling the feature, the defined dirty bit in PDE (Page Directory Entries), optional reserved bit trapping in CR3, PDEs, and PTEs.

  • tsc - Time Stamp Counter. The RDTSC instruction is supported, including CR4.TSD for controlling privilege.

  • msr - Model Specific Registers RDMSR and WRMSR Instructions. The RDMSR and WRMSR instructions are supported. Some of the MSRs are implementation dependent.

  • pae - Physical Address Extension. Physical addresses greater than 32 bits are supported: extended page table entry formats, an extra level in the page translation tables is defined, 2-MByte pages are supported instead of 4 Mbyte pages if PAE bit is 1. The actual number of address bits beyond 32 is not defined, and is implementation specific.

  • mce - Machine Check Exception. Exception 18 is defined for Machine Checks, including CR4.MCE for controlling the feature. This feature does not define the model-specific implementations of machine-check error logging,
reporting, and processor shutdowns. Machine Check exception handlers may have to depend on processor version to do model specific processing of the exception, or test for the presence of the Machine Check feature.

  • cx8 - CMPXCHG8B Instruction. The compare-and-exchange 8 bytes (64 bits) instruction is supported (implicitly locked and atomic).

  • apic - APIC On-Chip. The processor contains an Advanced Programmable Interrupt Controller (APIC), responding to memory mapped commands in the physical address range FFFE0000H to FFFE0FFFH (by default - some processors
permit the APIC to be relocated).

  • sep - SYSENTER and SYSEXIT Instructions. The SYSENTER and SYSEXIT and associated MSRs are supported.

  • mtrr - Memory Type Range Registers. MTRRs are supported. The MTRRcap MSR contains feature bits that describe what memory types are supported, how many variable MTRRs are supported, and whether fixed MTRRs are supported

  • pge - PTE Global Bit. The global bit in page directory entries (PDEs) and page table entries (PTEs) is supported, indicating TLB entries that are common to different processes and need not be flushed. The CR4.PGE bit controls this feature.

  • mca - Machine Check Architecture. The Machine Check Architecture, which provides a compatible mechanism for error reporting in P6 family, Pentium 4, Intel Xeon processors, and future processors, is supported. The MCG_CAP MSR contains feature bits describing how many banks of error reporting MSRs are supported.

  • cmov - Conditional Move Instructions. The conditional move instruction CMOV is supported. In addition, if x87 FPU is present as indicated by the CPUID.FPU feature bit, then the FCOMI and FCMOV instructions are supported
  • pat - Page Attribute Table. Page Attribute Table is supported. This feature augments the Memory Type Range Registers (MTRRs), allowing an operating system to specify attributes of memory on a 4K granularity through a linear address.

  • pse-36 36-Bit Page Size Extension. Extended 4-MByte pages that are capable of addressing physical memory beyond 4 GBytes are supported. This feature indicates that the upper four bits of the physical address of the 4-MByte page is encoded by bits 13-16 of the page directory entry.

  • psn - Processor Serial Number. The processor supports the 96-bit processor identification number feature and the feature is enabled.

  • clflush - CLFLUSH Instruction. CLFLUSH Instruction is supported.

  • ds - Debug Store. The processor supports the ability to write debug information into a memory resident buffer. This feature is used by the branch trace store (BTS) and precise event-based sampling (PEBS) facilities (see Chapter 18, Debugging and Performance Monitoring, in the IntelĀ® 64 and IA-32 Architectures Software Developers Manual, Volume 3B).

  • acpi - Thermal Monitor and Software Controlled Clock Facilities. The processor implements internal MSRs that allow processor temperature to be monitored and processor performance to be modulated in predefined duty cycles under software control.

  • mmx - Intel MMX Technology. The processor supports the Intel MMX technology.

  • fxsr - FXSAVE and FXRSTOR Instructions. The FXSAVE and FXRSTOR instructions are supported for fast save and restore of the floating point context. Presence of this bit also indicates that CR4.OSFXSR is available for an
operating system to indicate that it supports the FXSAVE and FXRSTOR instructions.

  • sse - SSE. The processor supports the SSE extensions.

  • sse2 - SSE2. The processor supports the SSE2 extensions.

  • ss - Self Snoop. The processor supports the management of conflicting memory types by performing a snoop of its own cache structure for transactions issued to the bus.

  • htt Multi-Threading. The physical processor package is capable of supporting more than one logical processor.

  • tm - Thermal Monitor. The processor implements the thermal monitor automatic thermal control circuitry (TCC).

  • pbe - Pending Break Enable. The processor supports the use of the FERR#/PBE# pin when the processor is in the stop-clock state (STPCLK# is asserted) to signal the processor that an interrupt is pending and that the processor should return to normal operation to handle the interrupt. Bit 10 (PBEenable) in the IA32_MISC_ENABLE MSR enables this capability.


Topic revision: r1 - 19 Aug 2007, HenningPerl
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