x86info

Detailed x86 CPU diagnostic information

TLDR

Display all CPU information

$ x86info -a

Show CPU feature flags

$ x86info -f

Show cache and TLB information

$ x86info -c

Estimate current clock speed

$ x86info -mhz

Show raw CPUID register values

$ x86info -r

Dump model-specific registers (requires root)

$ sudo x86info -m

Show verbose descriptions

$ x86info -v

Dump MP table (multiprocessor info)

$ sudo x86info -mp

SYNOPSIS

x86info [-a] [-c] [-f] [-m] [-mhz] [-mp] [-r] [-s] [-v]

x86info displays detailed diagnostic information about x86 CPUs, including processor identification, feature flags, cache topology, and model-specific registers. It queries the processor using the CPUID instruction and MSR (Model Specific Register) reads.The tool provides information similar to /proc/cpuinfo but with more detail, including cache associativity, TLB configuration, and raw CPUID data. It can identify the CPU vendor, family, model, and stepping, along with supported instruction set extensions.For full functionality, the kernel must have CPUID and MSR device drivers enabled, creating device files at /dev/cpu/\<n\>/cpuid and /dev/cpu/\<n\>/msr. Some options (MSR reading, MP table) require root privileges.

PARAMETERS

-a, --all

Show all available information. Equivalent to -c -f -m -r -mhz.

-c, --cache

Display TLB and cache sizes, including cache associativity.

-f, --flags

Show CPU feature flags (SSE, AVX, etc.).

-m, --msr

Dump model-specific registers. Requires root and supported processor.

-mhz, --mhz

Estimate current CPU clock rate.

-mp, --mptable

Dump MP table showing CPUs known to BIOS.

-r, --registers

Show raw register values from all possible CPUID calls.

-s, --show-machine-check

Display machine check exception information.

-v, --verbose

Show verbose descriptions of CPU features.

-?, --help

Display help message.

INSTALL

sudo apt install x86info

nix profile install nixpkgs#x86info

CAVEATS

Requires CPUID and MSR kernel modules for full functionality. MSR access requires root privileges. Model-specific register support varies by processor. Clock rate estimation may be inaccurate on systems with frequency scaling.

HISTORY

x86info was written by Dave Jones ([email protected]), who also contributed significantly to the Linux kernel's CPU identification code. The tool has been available since the early 2000s and provides detailed x86 CPU diagnostics not easily available through other means.