Re: [PATCH net-next 2/4] tools: ynl: allow setting recv() size

From: Donald Hunter <donald.hunter@gmail.com>
To: Jakub Kicinski <kuba@kernel.org>
Cc: davem@davemloft.net, netdev@vger.kernel.org, edumazet@google.com,
	 pabeni@redhat.com, jiri@resnulli.us
Subject: Re: [PATCH net-next 2/4] tools: ynl: allow setting recv() size
Date: Mon, 4 Mar 2024 13:38:51 +0000	[thread overview]
Message-ID: <CAD4GDZzkVJackAf2yhG1E5vypd2J=n23HD5Huu356JK1F1oLKA@mail.gmail.com> (raw)
In-Reply-To: <20240301230542.116823-3-kuba@kernel.org>

On Fri, 1 Mar 2024 at 23:05, Jakub Kicinski <kuba@kernel.org> wrote:
>
>  class YnlFamily(SpecFamily):
> -    def __init__(self, def_path, schema=None, process_unknown=False):
> +    def __init__(self, def_path, schema=None, process_unknown=False,
> +                 recv_size=131072):

An aside: what is the reason for choosing a 128k receive buffer? If I
remember correctly, netlink messages are capped at 32k.

>          super().__init__(def_path, schema)
>
>          self.include_raw = False
> @@ -423,6 +428,16 @@ genl_family_name_to_id = None
>          self.async_msg_ids = set()
>          self.async_msg_queue = []
>
> +        # Note that netlink will use conservative (min) message size for
> +        # the first dump recv() on the socket, our setting will only matter

I'm curious, why does it behave like this?

> +        # from the second recv() on.
> +        self._recv_size = recv_size