diff options
Diffstat (limited to 'python/vyos/utils')
| -rw-r--r-- | python/vyos/utils/__init__.py | 3 | ||||
| -rw-r--r-- | python/vyos/utils/cpu.py | 101 |
2 files changed, 103 insertions, 1 deletions
diff --git a/python/vyos/utils/__init__.py b/python/vyos/utils/__init__.py index 12ef2d3b8..1cd062a11 100644 --- a/python/vyos/utils/__init__.py +++ b/python/vyos/utils/__init__.py @@ -1,4 +1,4 @@ -# Copyright 2023 VyOS maintainers and contributors <maintainers@vyos.io> +# Copyright 2024 VyOS maintainers and contributors <maintainers@vyos.io> # # This library is free software; you can redistribute it and/or # modify it under the terms of the GNU Lesser General Public @@ -18,6 +18,7 @@ from vyos.utils import auth from vyos.utils import boot from vyos.utils import commit from vyos.utils import convert +from vyos.utils import cpu from vyos.utils import dict from vyos.utils import file from vyos.utils import io diff --git a/python/vyos/utils/cpu.py b/python/vyos/utils/cpu.py new file mode 100644 index 000000000..0f74add0e --- /dev/null +++ b/python/vyos/utils/cpu.py @@ -0,0 +1,101 @@ +# Copyright (C) 2022-2024 maintainers and contributors +# +# This library is free software; you can redistribute it and/or +# modify it under the terms of the GNU Lesser General Public +# License as published by the Free Software Foundation; either +# version 2.1 of the License, or (at your option) any later version. +# +# This library is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +# Lesser General Public License for more details. +# +# You should have received a copy of the GNU Lesser General Public +# License along with this library. If not, see <http://www.gnu.org/licenses/>. + +""" +Retrieves (or at least attempts to retrieve) the total number of real CPU cores +installed in a Linux system. + +The issue of core count is complicated by existence of SMT, e.g. Intel's Hyper Threading. +GNU nproc returns the number of LOGICAL cores, +which is 2x of the real cores if SMT is enabled. + +The idea is to find all physical CPUs and add up their core counts. +It has special cases for x86_64 and MAY work correctly on other architectures, +but nothing is certain. +""" + +import re + +def _read_cpuinfo(): + with open('/proc/cpuinfo', 'r') as f: + lines = f.read().strip() + return re.split(r'\n+', lines) + +def _split_line(l): + l = l.strip() + parts = re.split(r'\s*:\s*', l) + return (parts[0], ":".join(parts[1:])) + +def _find_cpus(cpuinfo_lines): + # Make a dict because it's more convenient to work with later, + # when we need to find physicall distinct CPUs there. + cpus = {} + + cpu_number = 0 + + for l in cpuinfo_lines: + key, value = _split_line(l) + if key == 'processor': + cpu_number = value + cpus[cpu_number] = {} + else: + cpus[cpu_number][key] = value + + return cpus + +def _find_physical_cpus(): + cpus = _find_cpus(_read_cpuinfo()) + + phys_cpus = {} + + for num in cpus: + if 'physical id' in cpus[num]: + # On at least some architectures, CPUs in different sockets + # have different 'physical id' field, e.g. on x86_64. + phys_id = cpus[num]['physical id'] + if phys_id not in phys_cpus: + phys_cpus[phys_id] = cpus[num] + else: + # On other architectures, e.g. on ARM, there's no such field. + # We just assume they are different CPUs, + # whether single core ones or cores of physical CPUs. + phys_cpus[num] = cpus[num] + + return phys_cpus + +def get_cpus(): + """ Returns a list of /proc/cpuinfo entries that belong to different CPUs. + """ + cpus_dict = _find_physical_cpus() + return list(cpus_dict.values()) + +def get_core_count(): + """ Returns the total number of physical CPU cores + (even if Hyper-Threading or another SMT is enabled and has inflated + the number of cores in /proc/cpuinfo) + """ + physical_cpus = _find_physical_cpus() + + core_count = 0 + + for num in physical_cpus: + # Some architectures, e.g. x86_64, include a field for core count. + # Since we found unique physical CPU entries, we can sum their core counts. + if 'cpu cores' in physical_cpus[num]: + core_count += int(physical_cpus[num]['cpu cores']) + else: + core_count += 1 + + return core_count |