[PATCH v7 14/21] dts: cpu docstring update
Yoan Picchi
yoan.picchi at foss.arm.com
Tue Nov 21 18:45:10 CET 2023
On 11/15/23 13:09, Juraj Linkeš wrote:
> Format according to the Google format and PEP257, with slight
> deviations.
>
> Signed-off-by: Juraj Linkeš <juraj.linkes at pantheon.tech>
> ---
> dts/framework/testbed_model/cpu.py | 196 +++++++++++++++++++++--------
> 1 file changed, 144 insertions(+), 52 deletions(-)
>
> diff --git a/dts/framework/testbed_model/cpu.py b/dts/framework/testbed_model/cpu.py
> index 8fe785dfe4..4edeb4a7c2 100644
> --- a/dts/framework/testbed_model/cpu.py
> +++ b/dts/framework/testbed_model/cpu.py
> @@ -1,6 +1,22 @@
> # SPDX-License-Identifier: BSD-3-Clause
> # Copyright(c) 2023 PANTHEON.tech s.r.o.
>
> +"""CPU core representation and filtering.
> +
> +This module provides a unified representation of logical CPU cores along
> +with filtering capabilities.
> +
> +When symmetric multiprocessing (SMP or multithreading) is enabled on a server,
> +the physical CPU cores are split into logical CPU cores with different IDs.
> +
> +:class:`LogicalCoreCountFilter` filters by the number of logical cores. It's possible to specify
> +the socket from which to filter the number of logical cores. It's also possible to not use all
> +logical CPU cores from each physical core (e.g. only the first logical core of each physical core).
> +
> +:class:`LogicalCoreListFilter` filters by logical core IDs. This mostly checks that
> +the logical cores are actually present on the server.
> +"""
> +
> import dataclasses
> from abc import ABC, abstractmethod
> from collections.abc import Iterable, ValuesView
> @@ -11,9 +27,17 @@
>
> @dataclass(slots=True, frozen=True)
> class LogicalCore(object):
> - """
> - Representation of a CPU core. A physical core is represented in OS
> - by multiple logical cores (lcores) if CPU multithreading is enabled.
> + """Representation of a logical CPU core.
> +
> + A physical core is represented in OS by multiple logical cores (lcores)
> + if CPU multithreading is enabled. When multithreading is disabled, their IDs are the same.
> +
> + Attributes:
> + lcore: The logical core ID of a CPU core. It's the same as `core` with
> + disabled multithreading.
> + core: The physical core ID of a CPU core.
> + socket: The physical socket ID where the CPU resides.
> + node: The NUMA node ID where the CPU resides.
> """
>
> lcore: int
> @@ -22,27 +46,36 @@ class LogicalCore(object):
> node: int
>
> def __int__(self) -> int:
> + """The CPU is best represented by the logical core, as that's what we configure in EAL."""
> return self.lcore
>
>
> class LogicalCoreList(object):
> - """
> - Convert these options into a list of logical core ids.
> - lcore_list=[LogicalCore1, LogicalCore2] - a list of LogicalCores
> - lcore_list=[0,1,2,3] - a list of int indices
> - lcore_list=['0','1','2-3'] - a list of str indices; ranges are supported
> - lcore_list='0,1,2-3' - a comma delimited str of indices; ranges are supported
> -
> - The class creates a unified format used across the framework and allows
> - the user to use either a str representation (using str(instance) or directly
> - in f-strings) or a list representation (by accessing instance.lcore_list).
> - Empty lcore_list is allowed.
> + r"""A unified way to store :class:`LogicalCore`\s.
> +
> + Create a unified format used across the framework and allow the user to use
> + either a :class:`str` representation (using ``str(instance)`` or directly in f-strings)
> + or a :class:`list` representation (by accessing the `lcore_list` property,
> + which stores logical core IDs).
> """
>
> _lcore_list: list[int]
> _lcore_str: str
>
> def __init__(self, lcore_list: list[int] | list[str] | list[LogicalCore] | str):
> + """Process `lcore_list`, then sort.
> +
> + There are four supported logical core list formats::
> +
> + lcore_list=[LogicalCore1, LogicalCore2] # a list of LogicalCores
> + lcore_list=[0,1,2,3] # a list of int indices
> + lcore_list=['0','1','2-3'] # a list of str indices; ranges are supported
> + lcore_list='0,1,2-3' # a comma delimited str of indices; ranges are supported
> +
> + Args:
> + lcore_list: Various ways to represent multiple logical cores.
> + Empty `lcore_list` is allowed.
> + """
> self._lcore_list = []
> if isinstance(lcore_list, str):
> lcore_list = lcore_list.split(",")
> @@ -60,6 +93,7 @@ def __init__(self, lcore_list: list[int] | list[str] | list[LogicalCore] | str):
>
> @property
> def lcore_list(self) -> list[int]:
> + """The logical core IDs."""
> return self._lcore_list
>
> def _get_consecutive_lcores_range(self, lcore_ids_list: list[int]) -> list[str]:
> @@ -89,28 +123,30 @@ def _get_consecutive_lcores_range(self, lcore_ids_list: list[int]) -> list[str]:
> return formatted_core_list
>
> def __str__(self) -> str:
> + """The consecutive ranges of logical core IDs."""
> return self._lcore_str
>
>
> @dataclasses.dataclass(slots=True, frozen=True)
> class LogicalCoreCount(object):
> - """
> - Define the number of logical cores to use.
> - If sockets is not None, socket_count is ignored.
> - """
> + """Define the number of logical cores per physical cores per sockets."""
>
> + #: Use this many logical cores per each physical core.
> lcores_per_core: int = 1
> + #: Use this many physical cores per each socket.
> cores_per_socket: int = 2
> + #: Use this many sockets.
> socket_count: int = 1
> + #: Use exactly these sockets. This takes precedence over `socket_count`,
> + #: so when `sockets` is not :data:`None`, `socket_count` is ignored.
> sockets: list[int] | None = None
>
>
> class LogicalCoreFilter(ABC):
> - """
> - Filter according to the input filter specifier. Each filter needs to be
> - implemented in a derived class.
> - This class only implements operations common to all filters, such as sorting
> - the list to be filtered beforehand.
> + """Common filtering class.
> +
> + Each filter needs to be implemented in a subclass. This base class sorts the list of cores
> + and defines the filtering method, which must be implemented by subclasses.
> """
>
> _filter_specifier: LogicalCoreCount | LogicalCoreList
> @@ -122,6 +158,17 @@ def __init__(
> filter_specifier: LogicalCoreCount | LogicalCoreList,
> ascending: bool = True,
> ):
> + """Filter according to the input filter specifier.
> +
> + The input `lcore_list` is copied and sorted by physical core before filtering.
> + The list is copied so that the original is left intact.
> +
> + Args:
> + lcore_list: The logical CPU cores to filter.
> + filter_specifier: Filter cores from `lcore_list` according to this filter.
> + ascending: Sort cores in ascending order (lowest to highest IDs). If data:`False`,
> + sort in descending order.
> + """
> self._filter_specifier = filter_specifier
>
> # sorting by core is needed in case hyperthreading is enabled
> @@ -132,31 +179,45 @@ def __init__(
>
> @abstractmethod
> def filter(self) -> list[LogicalCore]:
> - """
> - Use self._filter_specifier to filter self._lcores_to_filter
> - and return the list of filtered LogicalCores.
> - self._lcores_to_filter is a sorted copy of the original list,
> - so it may be modified.
> + r"""Filter the cores.
> +
> + Use `self._filter_specifier` to filter `self._lcores_to_filter` and return
> + the filtered :class:`LogicalCore`\s.
> + `self._lcores_to_filter` is a sorted copy of the original list, so it may be modified.
> +
> + Returns:
> + The filtered cores.
> """
>
>
> class LogicalCoreCountFilter(LogicalCoreFilter):
> - """
> + """Filter cores by specified counts.
> +
> Filter the input list of LogicalCores according to specified rules:
> - Use cores from the specified number of sockets or from the specified socket ids.
> - If sockets is specified, it takes precedence over socket_count.
> - From each of those sockets, use only cores_per_socket of cores.
> - And for each core, use lcores_per_core of logical cores. Hypertheading
> - must be enabled for this to take effect.
> - If ascending is True, use cores with the lowest numerical id first
> - and continue in ascending order. If False, start with the highest
> - id and continue in descending order. This ordering affects which
> - sockets to consider first as well.
> +
> + * The input `filter_specifier` is :class:`LogicalCoreCount`,
> + * Use cores from the specified number of sockets or from the specified socket ids,
> + * If `sockets` is specified, it takes precedence over `socket_count`,
> + * From each of those sockets, use only `cores_per_socket` of cores,
> + * And for each core, use `lcores_per_core` of logical cores. Hypertheading
> + must be enabled for this to take effect.
> """
>
> _filter_specifier: LogicalCoreCount
>
> def filter(self) -> list[LogicalCore]:
> + """Filter the cores according to :class:`LogicalCoreCount`.
> +
> + Start by filtering the allowed sockets. The cores matching the allowed socket are returned.
allowed socket*s*
> + The cores of each socket are stored in separate lists.
> +
> + Then filter the allowed physical cores from those lists of cores per socket. When filtering
> + physical cores, store the desired number of logical cores per physical core which then
> + together constitute the final filtered list.
> +
> + Returns:
> + The filtered cores.
> + """
> sockets_to_filter = self._filter_sockets(self._lcores_to_filter)
> filtered_lcores = []
> for socket_to_filter in sockets_to_filter:
> @@ -166,24 +227,37 @@ def filter(self) -> list[LogicalCore]:
> def _filter_sockets(
> self, lcores_to_filter: Iterable[LogicalCore]
> ) -> ValuesView[list[LogicalCore]]:
> - """
> - Remove all lcores that don't match the specified socket(s).
> - If self._filter_specifier.sockets is not None, keep lcores from those sockets,
> - otherwise keep lcores from the first
> - self._filter_specifier.socket_count sockets.
> + """Filter a list of cores per each allowed socket.
> +
> + The sockets may be specified in two ways, either a number or a specific list of sockets.
> + In case of a specific list, we just need to return the cores from those sockets.
> + If filtering a number of cores, we need to go through all cores and note which sockets
> + appear and only filter from the first n that appear.
> +
> + Args:
> + lcores_to_filter: The cores to filter. These must be sorted by the physical core.
> +
> + Returns:
> + A list of lists of logical CPU cores. Each list contains cores from one socket.
> """
> allowed_sockets: set[int] = set()
> socket_count = self._filter_specifier.socket_count
> if self._filter_specifier.sockets:
> + # when sockets in filter is specified, the sockets are already set
> socket_count = len(self._filter_specifier.sockets)
> allowed_sockets = set(self._filter_specifier.sockets)
>
> + # filter socket_count sockets from all sockets by checking the socket of each CPU
> filtered_lcores: dict[int, list[LogicalCore]] = {}
> for lcore in lcores_to_filter:
> if not self._filter_specifier.sockets:
> + # this is when sockets is not set, so we do the actual filtering
> + # when it is set, allowed_sockets is already defined and can't be changed
> if len(allowed_sockets) < socket_count:
> + # allowed_sockets is a set, so adding an existing socket won't re-add it
> allowed_sockets.add(lcore.socket)
> if lcore.socket in allowed_sockets:
> + # separate sockets per socket; this makes it easier in further processing
socket*s* per socket ?
> if lcore.socket in filtered_lcores:
> filtered_lcores[lcore.socket].append(lcore)
> else:
> @@ -200,12 +274,13 @@ def _filter_sockets(
> def _filter_cores_from_socket(
> self, lcores_to_filter: Iterable[LogicalCore]
> ) -> list[LogicalCore]:
> - """
> - Keep only the first self._filter_specifier.cores_per_socket cores.
> - In multithreaded environments, keep only
> - the first self._filter_specifier.lcores_per_core lcores of those cores.
> - """
> + """Filter a list of cores from the given socket.
> +
> + Go through the cores and note how many logical cores per physical core have been filtered.
>
> + Returns:
> + The filtered logical CPU cores.
> + """
> # no need to use ordered dict, from Python3.7 the dict
> # insertion order is preserved (LIFO).
> lcore_count_per_core_map: dict[int, int] = {}
> @@ -248,15 +323,21 @@ def _filter_cores_from_socket(
>
>
> class LogicalCoreListFilter(LogicalCoreFilter):
> - """
> - Filter the input list of Logical Cores according to the input list of
> - lcore indices.
> - An empty LogicalCoreList won't filter anything.
> + """Filter the logical CPU cores by logical CPU core IDs.
> +
> + This is a simple filter that looks at logical CPU IDs and only filter those that match.
> +
> + The input filter is :class:`LogicalCoreList`. An empty LogicalCoreList won't filter anything.
> """
>
> _filter_specifier: LogicalCoreList
>
> def filter(self) -> list[LogicalCore]:
> + """Filter based on logical CPU core ID.
> +
> + Return:
> + The filtered logical CPU cores.
> + """
> if not len(self._filter_specifier.lcore_list):
> return self._lcores_to_filter
>
> @@ -279,6 +360,17 @@ def lcore_filter(
> filter_specifier: LogicalCoreCount | LogicalCoreList,
> ascending: bool,
> ) -> LogicalCoreFilter:
> + """Factory for using the right filter with `filter_specifier`.
> +
> + Args:
> + core_list: The logical CPU cores to filter.
> + filter_specifier: The filter to use.
> + ascending: Sort cores in ascending order (lowest to highest IDs). If :data:`False`,
> + sort in descending order.
> +
> + Returns:
> + The filter matching `filter_specifier`.
> + """
> if isinstance(filter_specifier, LogicalCoreList):
> return LogicalCoreListFilter(core_list, filter_specifier, ascending)
> elif isinstance(filter_specifier, LogicalCoreCount):
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