# os/cpu-count
Return the number of logical CPUs available to the process. Used to size
worker pools (`os/run-async`, `http/serve-cluster`).
## Syntax
[os/cpu-count]
## Examples
[os/cpu-count] # → 16 (machine-dependent)
## Returns
A number — the logical CPU count reported by the OS, or `1` when the query
fails. Always at least 1.
## See Also
`os/run-async`, `http/serve-cluster`