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-rw-r--r--etc/spack/defaults/config.yaml12
-rw-r--r--lib/spack/docs/config_yaml.rst16
-rw-r--r--lib/spack/spack/build_environment.py38
-rw-r--r--lib/spack/spack/cmd/common/arguments.py13
-rw-r--r--lib/spack/spack/config.py4
-rw-r--r--lib/spack/spack/test/build_environment.py21
-rw-r--r--lib/spack/spack/test/cmd/common/arguments.py17
-rw-r--r--lib/spack/spack/util/cpus.py20
8 files changed, 97 insertions, 44 deletions
diff --git a/etc/spack/defaults/config.yaml b/etc/spack/defaults/config.yaml
index 7f0b9276ba..61c23f42df 100644
--- a/etc/spack/defaults/config.yaml
+++ b/etc/spack/defaults/config.yaml
@@ -142,11 +142,13 @@ config:
locks: true
- # The maximum number of jobs to use when running `make` in parallel,
- # always limited by the number of cores available. For instance:
- # - If set to 16 on a 4 cores machine `spack install` will run `make -j4`
- # - If set to 16 on a 18 cores machine `spack install` will run `make -j16`
- # If not set, Spack will use all available cores up to 16.
+ # The maximum number of jobs to use for the build system (e.g. `make`), when
+ # the -j flag is not given on the command line. Defaults to 16 when not set.
+ # Note that the maximum number of jobs is limited by the number of cores
+ # available, taking thread affinity into account when supported. For instance:
+ # - With `build_jobs: 16` and 4 cores available `spack install` will run `make -j4`
+ # - With `build_jobs: 16` and 32 cores available `spack install` will run `make -j16`
+ # - With `build_jobs: 2` and 4 cores available `spack install -j6` will run `make -j6`
# build_jobs: 16
diff --git a/lib/spack/docs/config_yaml.rst b/lib/spack/docs/config_yaml.rst
index 66df916193..631b8f6b1b 100644
--- a/lib/spack/docs/config_yaml.rst
+++ b/lib/spack/docs/config_yaml.rst
@@ -202,21 +202,23 @@ of builds.
Unless overridden in a package or on the command line, Spack builds all
packages in parallel. The default parallelism is equal to the number of
-cores on your machine, up to 16. Parallelism cannot exceed the number of
-cores available on the host. For a build system that uses Makefiles, this
-means running:
+cores available to the process, up to 16 (the default of ``build_jobs``).
+For a build system that uses Makefiles, this ``spack install`` runs:
- ``make -j<build_jobs>``, when ``build_jobs`` is less than the number of
- cores on the machine
+ cores available
- ``make -j<ncores>``, when ``build_jobs`` is greater or equal to the
- number of cores on the machine
+ number of cores available
If you work on a shared login node or have a strict ulimit, it may be
necessary to set the default to a lower value. By setting ``build_jobs``
to 4, for example, commands like ``spack install`` will run ``make -j4``
-instead of hogging every core.
+instead of hogging every core. To build all software in serial,
+set ``build_jobs`` to 1.
-To build all software in serial, set ``build_jobs`` to 1.
+Note that specifying the number of jobs on the command line always takes
+priority, so that ``spack install -j<n>`` always runs `make -j<n>`, even
+when that exceeds the number of cores available.
--------------------
``ccache``
diff --git a/lib/spack/spack/build_environment.py b/lib/spack/spack/build_environment.py
index f7fd76d82a..14bd7babf0 100644
--- a/lib/spack/spack/build_environment.py
+++ b/lib/spack/spack/build_environment.py
@@ -70,8 +70,7 @@ from spack.error import NoLibrariesError, NoHeadersError
from spack.util.executable import Executable
from spack.util.module_cmd import load_module, path_from_modules, module
from spack.util.log_parse import parse_log_events, make_log_context
-
-
+from spack.util.cpus import cpus_available
#
# This can be set by the user to globally disable parallel builds.
#
@@ -452,6 +451,38 @@ def set_build_environment_variables(pkg, env, dirty):
return env
+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): true when package supports parallel builds
+ command_line (int/None): command line override
+ config_default (int/None): config default number of jobs
+ max_cpus (int/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_variables_for_single_module(pkg, module):
"""Helper function to set module variables for single module."""
# Put a marker on this module so that it won't execute the body of this
@@ -460,8 +491,7 @@ def _set_variables_for_single_module(pkg, module):
if getattr(module, marker, False):
return
- jobs = spack.config.get('config:build_jobs', 16) if pkg.parallel else 1
- jobs = min(jobs, multiprocessing.cpu_count())
+ jobs = determine_number_of_jobs(parallel=pkg.parallel)
m = module
m.make_jobs = jobs
diff --git a/lib/spack/spack/cmd/common/arguments.py b/lib/spack/spack/cmd/common/arguments.py
index e6a0edd599..759fdfc498 100644
--- a/lib/spack/spack/cmd/common/arguments.py
+++ b/lib/spack/spack/cmd/common/arguments.py
@@ -5,7 +5,6 @@
import argparse
-import multiprocessing
import spack.cmd
import spack.config
@@ -102,22 +101,10 @@ class SetParallelJobs(argparse.Action):
'[expected a positive integer, got "{1}"]'
raise ValueError(msg.format(option_string, jobs))
- jobs = min(jobs, multiprocessing.cpu_count())
spack.config.set('config:build_jobs', jobs, scope='command_line')
setattr(namespace, 'jobs', jobs)
- @property
- def default(self):
- # This default is coded as a property so that look-up
- # of this value is done only on demand
- return min(spack.config.get('config:build_jobs', 16),
- multiprocessing.cpu_count())
-
- @default.setter
- def default(self, value):
- pass
-
class DeptypeAction(argparse.Action):
"""Creates a tuple of valid dependency types from a deptype argument."""
diff --git a/lib/spack/spack/config.py b/lib/spack/spack/config.py
index 4f7e61ea69..63839cfb05 100644
--- a/lib/spack/spack/config.py
+++ b/lib/spack/spack/config.py
@@ -35,7 +35,6 @@ import functools
import os
import re
import sys
-import multiprocessing
from contextlib import contextmanager
from six import iteritems
from ordereddict_backport import OrderedDict
@@ -61,6 +60,7 @@ import spack.schema.config
import spack.schema.upstreams
import spack.schema.env
from spack.error import SpackError
+from spack.util.cpus import cpus_available
# Hacked yaml for configuration files preserves line numbers.
import spack.util.spack_yaml as syaml
@@ -110,7 +110,7 @@ config_defaults = {
'verify_ssl': True,
'checksum': True,
'dirty': False,
- 'build_jobs': min(16, multiprocessing.cpu_count()),
+ 'build_jobs': min(16, cpus_available()),
'build_stage': '$tempdir/spack-stage',
'concretizer': 'original',
}
diff --git a/lib/spack/spack/test/build_environment.py b/lib/spack/spack/test/build_environment.py
index 28f6aefcb8..841a723f96 100644
--- a/lib/spack/spack/test/build_environment.py
+++ b/lib/spack/spack/test/build_environment.py
@@ -13,9 +13,9 @@ import spack.config
import spack.spec
from spack.paths import build_env_path
from spack.build_environment import dso_suffix, _static_to_shared_library
+from spack.build_environment import determine_number_of_jobs
from spack.util.executable import Executable
from spack.util.environment import EnvironmentModifications
-
from llnl.util.filesystem import LibraryList, HeaderList
@@ -339,3 +339,22 @@ def test_setting_dtags_based_on_config(
dtags_to_add = modifications['SPACK_DTAGS_TO_ADD'][0]
assert dtags_to_add.value == expected_flag
+
+
+def test_build_jobs_sequential_is_sequential():
+ assert determine_number_of_jobs(
+ parallel=False, command_line=8, config_default=8, max_cpus=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) == 10
+ assert determine_number_of_jobs(
+ parallel=True, command_line=10, config_default=100, max_cpus=100) == 10
+
+
+def test_build_jobs_defaults():
+ assert determine_number_of_jobs(
+ parallel=True, command_line=None, config_default=1, max_cpus=10) == 1
+ assert determine_number_of_jobs(
+ parallel=True, command_line=None, config_default=100, max_cpus=10) == 10
diff --git a/lib/spack/spack/test/cmd/common/arguments.py b/lib/spack/spack/test/cmd/common/arguments.py
index 2a290d5d43..27648ee383 100644
--- a/lib/spack/spack/test/cmd/common/arguments.py
+++ b/lib/spack/spack/test/cmd/common/arguments.py
@@ -4,11 +4,9 @@
# SPDX-License-Identifier: (Apache-2.0 OR MIT)
import argparse
-import multiprocessing
import pytest
-
import spack.cmd
import spack.cmd.common.arguments as arguments
import spack.config
@@ -27,20 +25,15 @@ def job_parser():
yield p
-@pytest.mark.parametrize("ncores", [1, 2, 4, 8, 16, 32])
-def test_setting_jobs_flag(job_parser, ncores, monkeypatch):
- monkeypatch.setattr(multiprocessing, 'cpu_count', lambda: ncores)
+def test_setting_jobs_flag(job_parser):
namespace = job_parser.parse_args(['-j', '24'])
- expected = min(24, ncores)
- assert namespace.jobs == expected
- assert spack.config.get('config:build_jobs') == expected
+ assert namespace.jobs == 24
+ assert spack.config.get('config:build_jobs', scope='command_line') == 24
-@pytest.mark.parametrize("ncores", [1, 2, 4, 8, 16, 32])
-def test_omitted_job_flag(job_parser, ncores, monkeypatch):
- monkeypatch.setattr(multiprocessing, 'cpu_count', lambda: ncores)
+def test_omitted_job_flag(job_parser):
namespace = job_parser.parse_args([])
- assert namespace.jobs == min(ncores, 16)
+ assert namespace.jobs is None
assert spack.config.get('config:build_jobs') is None
diff --git a/lib/spack/spack/util/cpus.py b/lib/spack/spack/util/cpus.py
new file mode 100644
index 0000000000..9fa10c87a8
--- /dev/null
+++ b/lib/spack/spack/util/cpus.py
@@ -0,0 +1,20 @@
+# Copyright 2013-2021 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 os
+import multiprocessing
+
+
+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()
generated by cgit v1.2.3-60-g2f50 (git 2.42.0) at 2024-06-28 21:51:31 +0000