| from __future__ import annotations |
|
|
| import os |
| from dataclasses import dataclass |
| from typing import Any, Dict |
|
|
|
|
| AUTO_MINUS_FOUR = "auto-minus-4" |
|
|
|
|
| @dataclass(frozen=True) |
| class ThreadAllocation: |
| policy: str |
| system_threads: int |
| reserve_threads: int |
| threads_used: int |
|
|
|
|
| def detect_system_threads() -> int: |
| return max(1, int(os.cpu_count() or 1)) |
|
|
|
|
| def resolve_threads_used( |
| configured_value: Any, |
| *, |
| reserve_threads: int = 4, |
| system_threads: int | None = None, |
| ) -> ThreadAllocation: |
| total = max(1, int(system_threads or detect_system_threads())) |
| reserve = max(0, int(reserve_threads)) |
|
|
| policy_raw = configured_value if configured_value is not None else AUTO_MINUS_FOUR |
| policy = str(policy_raw).strip().lower() |
|
|
| if policy in {"", "auto", AUTO_MINUS_FOUR}: |
| used = max(1, total - reserve) |
| return ThreadAllocation( |
| policy=AUTO_MINUS_FOUR, |
| system_threads=total, |
| reserve_threads=reserve, |
| threads_used=used, |
| ) |
|
|
| try: |
| used = max(1, int(policy_raw)) |
| except (TypeError, ValueError) as exc: |
| raise ValueError( |
| f"Invalid backend.parallel_jobs value `{configured_value}`. Use integer or `{AUTO_MINUS_FOUR}`." |
| ) from exc |
|
|
| return ThreadAllocation( |
| policy="fixed", |
| system_threads=total, |
| reserve_threads=reserve, |
| threads_used=min(total, used), |
| ) |
|
|
|
|
| def enforce_thread_fairness(config: Dict[str, Any], *, reserve_threads: int = 4) -> ThreadAllocation: |
| backend = config.setdefault("backend", {}) |
| configured = backend.get("parallel_jobs", AUTO_MINUS_FOUR) |
| alloc = resolve_threads_used(configured, reserve_threads=reserve_threads) |
|
|
| backend["parallel_jobs"] = int(alloc.threads_used) |
| backend["thread_policy"] = alloc.policy |
|
|
| runtime = config.setdefault("runtime", {}) |
| runtime["system_threads"] = int(alloc.system_threads) |
| runtime["reserve_threads"] = int(alloc.reserve_threads) |
| runtime["threads_used"] = int(alloc.threads_used) |
| runtime["thread_policy"] = alloc.policy |
| runtime["thread_formula"] = "threads_used = max(1, system_threads - 4)" |
| return alloc |
|
|
|
|
