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From: "Toke Høiland-Jørgensen" <toke@redhat•com>
To: Paolo Abeni <pabeni@redhat•com>, netdev@vger•kernel.org
Cc: "David S. Miller" <davem@davemloft•net>,
	Jakub Kicinski <kuba@kernel•org>
Subject: Re: [RFC PATCH 2/3] veth: make queues nr configurable via kernel module params
Date: Fri, 09 Jul 2021 12:24:48 +0200	[thread overview]
Message-ID: <875yxjvl73.fsf@toke.dk> (raw)
In-Reply-To: <480e7a960c26c9ab84efe59ed706f1a1a459d38c.1625823139.git.pabeni@redhat.com>

Paolo Abeni <pabeni@redhat•com> writes:

> This allows configuring the number of tx and rx queues at
> module load time. A single module parameter controls
> both the default number of RX and TX queues created
> at device registration time.
>
> Signed-off-by: Paolo Abeni <pabeni@redhat•com>
> ---
>  drivers/net/veth.c | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
>
> diff --git a/drivers/net/veth.c b/drivers/net/veth.c
> index 10360228a06a..787b4ad2cc87 100644
> --- a/drivers/net/veth.c
> +++ b/drivers/net/veth.c
> @@ -27,6 +27,11 @@
>  #include <linux/bpf_trace.h>
>  #include <linux/net_tstamp.h>
>  
> +static int queues_nr	= 1;
> +
> +module_param(queues_nr, int, 0644);
> +MODULE_PARM_DESC(queues_nr, "Max number of RX and TX queues (default = 1)");

Adding new module parameters is generally discouraged. Also, it's sort
of a cumbersome API that you'll have to set this first, then re-create
the device, and then use channels to get the number you want.

So why not just default to allocating num_possible_cpus() number of
queues? Arguably that is the value that makes the most sense from a
scalability point of view anyway, but if we're concerned about behaviour
change (are we?), we could just default real_num_*_queues to 1, so that
the extra queues have to be explicitly enabled by ethtool?

-Toke


  reply	other threads:[~2021-07-09 10:24 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-09  9:39 [RFC PATCH 0/3] veth: more flexible channels number configuration Paolo Abeni
2021-07-09  9:39 ` [RFC PATCH 1/3] veth: implement support for set_channel ethtool op Paolo Abeni
2021-07-09 10:15   ` Toke Høiland-Jørgensen
2021-07-09 10:49     ` Paolo Abeni
2021-07-09 11:36       ` Toke Høiland-Jørgensen
2021-07-09 14:38       ` Paolo Abeni
2021-07-09 15:23         ` Toke Høiland-Jørgensen
2021-07-09 16:35           ` Paolo Abeni
2021-07-09 19:56             ` Jakub Kicinski
2021-07-09 19:54   ` Jakub Kicinski
2021-07-12  1:44     ` David Ahern
2021-07-12 10:45       ` Paolo Abeni
2021-07-12 15:23         ` Jakub Kicinski
2021-07-09  9:39 ` [RFC PATCH 2/3] veth: make queues nr configurable via kernel module params Paolo Abeni
2021-07-09 10:24   ` Toke Høiland-Jørgensen [this message]
2021-07-09 15:33     ` Paolo Abeni
2021-07-09 16:12       ` Toke Høiland-Jørgensen
2021-07-09  9:39 ` [RFC PATCH 3/3] selftests: net: veth: add tests for set_channel Paolo Abeni

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