move determine_number_of_jobs into spack.util.cpus, use it in concretize (#37620)

7 files changed, 86 insertions, 46 deletions

diff --git a/lib/spack/spack/bootstrap/environment.py b/lib/spack/spack/bootstrap/environment.py
index a2086160f6..2a2fc37b45 100644
--- a/lib/spack/spack/bootstrap/environment.py
+++ b/lib/spack/spack/bootstrap/environment.py
@@ -15,9 +15,9 @@ import archspec.cpu
 
 from llnl.util import tty
 
-import spack.build_environment
 import spack.environment
 import spack.tengine
+import spack.util.cpus
 import spack.util.executable
 from spack.environment import depfile
 
@@ -137,7 +137,7 @@ class BootstrapEnvironment(spack.environment.Environment):
             "-C",
             str(self.environment_root()),
             "-j",
-            str(spack.build_environment.determine_number_of_jobs(parallel=True)),
+            str(spack.util.cpus.determine_number_of_jobs(parallel=True)),
             **kwargs,
         )
 
diff --git a/lib/spack/spack/build_environment.py b/lib/spack/spack/build_environment.py
index 7ecde73b8a..723f398ae6 100644
--- a/lib/spack/spack/build_environment.py
+++ b/lib/spack/spack/build_environment.py
@@ -68,7 +68,7 @@ import spack.util.pattern
 from spack.error import NoHeadersError, NoLibrariesError
 from spack.install_test import spack_install_test_log
 from spack.installer import InstallError
-from spack.util.cpus import cpus_available
+from spack.util.cpus import determine_number_of_jobs
 from spack.util.environment import (
     SYSTEM_DIRS,
     EnvironmentModifications,
@@ -537,39 +537,6 @@ def set_wrapper_variables(pkg, env):
     env.set(SPACK_RPATH_DIRS, ":".join(rpath_dirs))
 
 
-def determine_number_of_jobs(
-    parallel=False, command_line=None, config_default=None, max_cpus=None
-):
-    """
-    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 (bool or None): true when package supports parallel builds
-        command_line (int or None): command line override
-        config_default (int or None): config default number of jobs
-        max_cpus (int or None): maximum number of CPUs available. When None, this
-            value is automatically determined.
-    """
-    if not parallel:
-        return 1
-
-    if command_line is None and "command_line" in spack.config.scopes():
-        command_line = spack.config.get("config:build_jobs", scope="command_line")
-
-    if command_line is not None:
-        return command_line
-
-    max_cpus = max_cpus or cpus_available()
-
-    # in some rare cases _builtin config may not be set, so default to max 16
-    config_default = config_default or spack.config.get("config:build_jobs", 16)
-
-    return min(max_cpus, config_default)
-
-
 def set_module_variables_for_package(pkg):
     """Populate the Python module of a package with some useful global names.
     This makes things easier for package writers.
diff --git a/lib/spack/spack/build_systems/racket.py b/lib/spack/spack/build_systems/racket.py
index 8a07773a29..7dd0b23b01 100644
--- a/lib/spack/spack/build_systems/racket.py
+++ b/lib/spack/spack/build_systems/racket.py
@@ -10,9 +10,10 @@ import llnl.util.lang as lang
 import llnl.util.tty as tty
 
 import spack.builder
-from spack.build_environment import SPACK_NO_PARALLEL_MAKE, determine_number_of_jobs
+from spack.build_environment import SPACK_NO_PARALLEL_MAKE
 from spack.directives import build_system, extends, maintainers
 from spack.package_base import PackageBase
+from spack.util.cpus import determine_number_of_jobs
 from spack.util.environment import env_flag
 from spack.util.executable import Executable, ProcessError
 
@@ -92,7 +93,7 @@ class RacketBuilder(spack.builder.Builder):
                 "--copy",
                 "-i",
                 "-j",
-                str(determine_number_of_jobs(parallel)),
+                str(determine_number_of_jobs(parallel=parallel)),
                 "--",
                 os.getcwd(),
             ]
diff --git a/lib/spack/spack/environment/environment.py b/lib/spack/spack/environment/environment.py
index 8eb7edab40..bf61444f9a 100644
--- a/lib/spack/spack/environment/environment.py
+++ b/lib/spack/spack/environment/environment.py
@@ -1504,7 +1504,7 @@ class Environment:
         start = time.time()
         max_processes = min(
             len(arguments),  # Number of specs
-            spack.config.get("config:build_jobs"),  # Cap on build jobs
+            spack.util.cpus.determine_number_of_jobs(parallel=True),
         )
 
         # TODO: revisit this print as soon as darwin is parallel too
diff --git a/lib/spack/spack/package.py b/lib/spack/spack/package.py
index 1e0a9eb655..b73d82e256 100644
--- a/lib/spack/spack/package.py
+++ b/lib/spack/spack/package.py
@@ -96,6 +96,7 @@ from spack.package_base import (
     on_package_attributes,
 )
 from spack.spec import InvalidSpecDetected, Spec
+from spack.util.cpus import determine_number_of_jobs
 from spack.util.executable import *
 from spack.variant import (
     any_combination_of,
diff --git a/lib/spack/spack/test/build_environment.py b/lib/spack/spack/test/build_environment.py
index 0ee5a345df..90f3fb378e 100644
--- a/lib/spack/spack/test/build_environment.py
+++ b/lib/spack/spack/test/build_environment.py
@@ -16,8 +16,9 @@ import spack.config
 import spack.package_base
 import spack.spec
 import spack.util.spack_yaml as syaml
-from spack.build_environment import _static_to_shared_library, determine_number_of_jobs, dso_suffix
+from spack.build_environment import _static_to_shared_library, dso_suffix
 from spack.paths import build_env_path
+from spack.util.cpus import determine_number_of_jobs
 from spack.util.environment import EnvironmentModifications
 from spack.util.executable import Executable
 from spack.util.path import Path, convert_to_platform_path
@@ -442,7 +443,7 @@ def test_parallel_false_is_not_propagating(default_mock_concretization):
 
     spack.build_environment.set_module_variables_for_package(s["b"].package)
     assert s["b"].package.module.make_jobs == spack.build_environment.determine_number_of_jobs(
-        s["b"].package.parallel
+        parallel=s["b"].package.parallel
     )
 
 
@@ -474,28 +475,62 @@ def test_setting_dtags_based_on_config(config_setting, expected_flag, config, mo
 
 def test_build_jobs_sequential_is_sequential():
     assert (
-        determine_number_of_jobs(parallel=False, command_line=8, config_default=8, max_cpus=8) == 1
+        determine_number_of_jobs(
+            parallel=False,
+            max_cpus=8,
+            config=spack.config.Configuration(
+                spack.config.InternalConfigScope("command_line", {"config": {"build_jobs": 8}}),
+                spack.config.InternalConfigScope("defaults", {"config": {"build_jobs": 8}}),
+            ),
+        )
+        == 1
     )
 
 
 def test_build_jobs_command_line_overrides():
     assert (
-        determine_number_of_jobs(parallel=True, command_line=10, config_default=1, max_cpus=1)
+        determine_number_of_jobs(
+            parallel=True,
+            max_cpus=1,
+            config=spack.config.Configuration(
+                spack.config.InternalConfigScope("command_line", {"config": {"build_jobs": 10}}),
+                spack.config.InternalConfigScope("defaults", {"config": {"build_jobs": 1}}),
+            ),
+        )
         == 10
     )
     assert (
-        determine_number_of_jobs(parallel=True, command_line=10, config_default=100, max_cpus=100)
+        determine_number_of_jobs(
+            parallel=True,
+            max_cpus=100,
+            config=spack.config.Configuration(
+                spack.config.InternalConfigScope("command_line", {"config": {"build_jobs": 10}}),
+                spack.config.InternalConfigScope("defaults", {"config": {"build_jobs": 100}}),
+            ),
+        )
         == 10
     )
 
 
 def test_build_jobs_defaults():
     assert (
-        determine_number_of_jobs(parallel=True, command_line=None, config_default=1, max_cpus=10)
+        determine_number_of_jobs(
+            parallel=True,
+            max_cpus=10,
+            config=spack.config.Configuration(
+                spack.config.InternalConfigScope("defaults", {"config": {"build_jobs": 1}})
+            ),
+        )
         == 1
     )
     assert (
-        determine_number_of_jobs(parallel=True, command_line=None, config_default=100, max_cpus=10)
+        determine_number_of_jobs(
+            parallel=True,
+            max_cpus=10,
+            config=spack.config.Configuration(
+                spack.config.InternalConfigScope("defaults", {"config": {"build_jobs": 100}})
+            ),
+        )
         == 10
     )
 
diff --git a/lib/spack/spack/util/cpus.py b/lib/spack/spack/util/cpus.py
index acb6569b1d..b8b371ebb0 100644
--- a/lib/spack/spack/util/cpus.py
+++ b/lib/spack/spack/util/cpus.py
@@ -5,6 +5,9 @@
 
 import multiprocessing
 import os
+from typing import Optional
+
+import spack.config
 
 
 def cpus_available():
@@ -18,3 +21,36 @@ def cpus_available():
         return len(os.sched_getaffinity(0))  # novermin
     except Exception:
         return multiprocessing.cpu_count()
+
+
+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))