KTSTR_KERNEL_PARALLELISM_ENV

Constant KTSTR_KERNEL_PARALLELISM_ENV 

Source
pub const KTSTR_KERNEL_PARALLELISM_ENV: &str = "KTSTR_KERNEL_PARALLELISM";
Expand description

Name of the environment variable that overrides the rayon pool width used by cargo ktstr’s resolve_kernel_set to fan out per-spec kernel resolves (download / git-clone / build) in parallel. Default cap is available_parallelism() — the host’s logical CPU count — chosen so download streams do not outnumber threads the host can drive without thrashing a contended local network (kernel.org CDN per-IP throttle, developer ISP, CI shared NIC).

Operators override when the default is wrong for their environment: a fast NIC + slow CPU benefits from raising the cap above logical-CPU count to keep more downloads in flight; a contended CI runner with concurrent jobs benefits from lowering it to 1 or 2 to leave bandwidth for siblings; a multi-version --kernel A..Z resolve on a workstation may want a hand-tuned middle value to balance throughput against background load.

Parsed as usize; 0 and unparseable values fall through to the default cap so a typoed export does not silently disable parallelism. Leading/trailing whitespace is trimmed before parsing so a shell-quoted =" 8 " behaves the same as the unquoted form. Read by crate::cli::resolve_kernel_parallelism (the helper that combines this env value with the available_parallelism() fallback) so the parsing rules live in one place.

Single source of truth so the name is not spelled by hand at each reader; if the name ever changes, the change lands in one place instead of fanning out to every call site.