Source code for spack.util.cpus

# Copyright 2013-2024 Lawrence Livermore National Security, LLC and other
# Spack Project Developers. See the top-level COPYRIGHT file for details.
# SPDX-License-Identifier: (Apache-2.0 OR MIT)

import multiprocessing
import os
from typing import Optional

import spack.config

[docs] def cpus_available(): """ Returns the number of CPUs available for the current process, or the number of phyiscal CPUs when that information cannot be retrieved. The number of available CPUs might differ from the number of physical CPUs when using spack through Slurm or container runtimes. """ try: return len(os.sched_getaffinity(0)) # novermin except Exception: return multiprocessing.cpu_count()
[docs] def determine_number_of_jobs( *, parallel: bool = False, max_cpus: int = cpus_available(), config: Optional["spack.config.Configuration"] = None, ) -> int: """ Packages that require sequential builds need 1 job. Otherwise we use the number of jobs set on the command line. If not set, then we use the config defaults (which is usually set through the builtin config scope), but we cap to the number of CPUs available to avoid oversubscription. Parameters: parallel: true when package supports parallel builds max_cpus: maximum number of CPUs to use (defaults to cpus_available()) config: configuration object (defaults to global config) """ if not parallel: return 1 cfg = config or spack.config.CONFIG # Command line overrides all try: command_line = cfg.get("config:build_jobs", default=None, scope="command_line") if command_line is not None: return command_line except ValueError: pass return min(max_cpus, cfg.get("config:build_jobs", 16))