Re: [PATCH 2/4] dts: Use First Core Logic Change

[Jeremy Spewock <jspewock@iol.unh.edu>]

On Thu, Jun 13, 2024 at 4:21 PM Nicholas Pratte <npratte@iol.unh.edu> wrote:
>
> Removed use_first_core from the conf.yaml in favor of determining this
> within the framework. use_first_core continue to serve a purpose in that
> it is only enabled when core 0 is explicitly provided in the
> configuration. Any other configuration, including "" or "any," will
> omit core 0.
>
> Documentation reworks are included to reflect the changes made.
>
> Bugzilla ID: 1360
> Signed-off-by: Nicholas Pratte <npratte@iol.unh.edu>
>
> ---
>  doc/guides/tools/dts.rst                   |  9 +++------
>  dts/conf.yaml                              |  3 +--
>  dts/framework/config/__init__.py           | 11 +++++++----
>  dts/framework/config/conf_yaml_schema.json |  6 +-----
>  dts/framework/testbed_model/node.py        |  9 +++++++++
>  5 files changed, 21 insertions(+), 17 deletions(-)
>
> diff --git a/doc/guides/tools/dts.rst b/doc/guides/tools/dts.rst
> index da85295db9..fbb5c6f17b 100644
> --- a/doc/guides/tools/dts.rst
> +++ b/doc/guides/tools/dts.rst
> @@ -546,15 +546,12 @@ involved in the testing. These can be defined with the following mappings:
>     +-----------------------+---------------------------------------------------------------------------------------+
>     | ``os``                | The operating system of this node. See `OS`_ for supported values.                    |
>     +-----------------------+---------------------------------------------------------------------------------------+
> -   | ``lcores``            | | (*optional*, defaults to 1) *string* – Comma-separated list of logical              |
> -   |                       | | cores to use. An empty string means use all lcores.                                 |
> +   | ``lcores``            | | (*optional*, defaults to 1 if not used) *string* – Comma-separated list of logical  |

I think just leaving this as "defaults to 1" is fine here. It's more
explicit to say "if it isn't used", but just saying it defaults I
think implies that enough.

> +   |                       | | cores to use. An empty string means use all lcores except core 0. core 0 is used    |
> +   |                       | | only when explicitly specified                                                      |
>     |                       |                                                                                       |
>     |                       | **Example**: ``1,2,3,4,5,18-22``                                                      |
>     +-----------------------+---------------------------------------------------------------------------------------+
> -   | ``use_first_core``    | (*optional*, defaults to ``false``) *boolean*                                         |
> -   |                       |                                                                                       |
> -   |                       | Indicates whether DPDK should use only the first physical core or not.                |
> -   +-----------------------+---------------------------------------------------------------------------------------+
>     | ``memory_channels``   | (*optional*, defaults to 1) *integer*                                                 |
>     |                       |                                                                                       |
>     |                       | The number of the memory channels to use.                                             |
<snip>
> diff --git a/dts/framework/config/__init__.py b/dts/framework/config/__init__.py
> index 5a127a1207..6bc290a56a 100644
> --- a/dts/framework/config/__init__.py
> +++ b/dts/framework/config/__init__.py
> @@ -245,6 +245,9 @@ def from_dict(
>                  hugepage_config_dict["force_first_numa"] = False
>              hugepage_config = HugepageConfiguration(**hugepage_config_dict)
>
> +        lcores = "1" if "lcores" not in d else d["lcores"] if "any" not in d["lcores"] else ""
> +        use_first_core = "0" in lcores
> +
>          # The calls here contain duplicated code which is here because Mypy doesn't
>          # properly support dictionary unpacking with TypedDicts
>          if "traffic_generator" in d:
> @@ -255,8 +258,8 @@ def from_dict(
>                  password=d.get("password"),
>                  arch=Architecture(d["arch"]),
>                  os=OS(d["os"]),
> -                lcores=d.get("lcores", "1"),
> -                use_first_core=d.get("use_first_core", False),
> +                lcores=lcores,
> +                use_first_core=use_first_core,

I wonder if we could completely remove the "use_first_core" attribute
from the config classes. It seems like it's only used when you're
getting remote CPUs to skip core 0 based on the condition. With these
new changes it seems like we just assume that if 0 is in the list, we
will use it, otherwise we simply won't, so I don't think we need this
condition to detect whether we should skip or not anymore, do we?

>                  hugepages=hugepage_config,
>                  ports=[PortConfig.from_dict(d["name"], port) for port in d["ports"]],
>                  traffic_generator=TrafficGeneratorConfig.from_dict(d["traffic_generator"]),
> @@ -269,8 +272,8 @@ def from_dict(
>                  password=d.get("password"),
>                  arch=Architecture(d["arch"]),
>                  os=OS(d["os"]),
> -                lcores=d.get("lcores", "1"),
> -                use_first_core=d.get("use_first_core", False),
> +                lcores=lcores,
> +                use_first_core=use_first_core,
>                  hugepages=hugepage_config,
>                  ports=[PortConfig.from_dict(d["name"], port) for port in d["ports"]],
>                  memory_channels=d.get("memory_channels", 1),
<snip>
> diff --git a/dts/framework/testbed_model/node.py b/dts/framework/testbed_model/node.py
> index 74061f6262..470cd18e30 100644
> --- a/dts/framework/testbed_model/node.py
> +++ b/dts/framework/testbed_model/node.py
> @@ -93,6 +93,15 @@ def __init__(self, node_config: NodeConfiguration):
>              self.lcores, LogicalCoreList(self.config.lcores)
>          ).filter()
>
> +        if LogicalCore(lcore=0, core=0, socket=0, node=0) in self.lcores:

This condition fits if you completely remove the `use_first_core`
boolean from the NodeConfiguration, but if we decide not to I think it
could be shortened to just:

if config.use_first_core:



> +            self._logger.info(
> +                """
> +                WARNING: First core being used;
> +                using the first core is considered risky and should only
> +                be done by advanced users.
> +                """
> +            )
> +
>          self._other_sessions = []
>          self.virtual_devices = []
>          self._init_ports()
> --
> 2.44.0
>