Get the number of CPU cores available on the system.

cpu

cpus

core

processor

hardware

system

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Author

justjavac

Version

0.1.10

License

MIT

Repository

github.com/justjavac/moonbit-num-cpus

Last updated

8 days ago

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#moonbit-num-cpus

fn main {
  let logical = @num_cpus.get()
  let physical = @num_cpus.get_physical()
  println("logical: \{logical}, physical: \{physical}")
}

get

source

fn get() -> Int

Get the number of CPU cores available on the system.

This function returns the number of logical CPU cores, which includes hyperthreading cores if available. For example, on a quad-core processor with hyperthreading, this would return 8.

The function uses FFI (Foreign Function Interface) to call native system APIs to retrieve the CPU count information.

Returns:

The number of logical CPU cores available on the system.

Example:

let logical_cores = @num_cpus.get()
println("Logical CPU cores: \{logical_cores}")

Note:

On multi-threaded systems, this includes all logical cores
The result is cached by the operating system and reflects the current hardware configuration
This function is thread-safe

get_physical

source

fn get_physical() -> Int

Get the number of physical CPU cores on the system.

This function returns the number of physical CPU cores, excluding hyperthreading. For example, on a quad-core processor with hyperthreading, this would return 4 (the actual physical cores), not 8.

The function uses FFI to call native system APIs that can distinguish between physical and logical cores.

Returns:

The number of physical CPU cores (not including hyperthreading).

Example:

let physical_cores = @num_cpus.get_physical()
let logical_cores = @num_cpus.get()
println("Physical cores: \{physical_cores}")
println("Logical cores: \{logical_cores}")
println("Hyperthreading ratio: \{logical_cores / physical_cores}")

Note:

This count excludes logical cores created by hyperthreading
On systems without hyperthreading, this will return the same value as get()
The implementation may fall back to logical core count on some platforms
This function is thread-safe

Source Files

num_cpus.mbt

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num_cpus

#moonbit-num-cpus

#get

#get_physical

Source Files

get

get_physical