Re: [RFC][PATCH V2 2/3] examples/vhost: Add vswitch command line options

[Yuanhan Liu <yuanhan.liu@linux.intel.com>]

On Mon, Sep 05, 2016 at 04:24:30PM +0530, Pankaj Chauhan wrote:
> Add command line options for selecting switch implementation
> and maximum ports for the vswitch.following are two new command
> line options:
> 
> --switch <switch_name> [char string, Selects the switch imlementation]
> --max-ports<port_count> [int, selects maximum number of ports to support]
> 
> For example:
> 
> $ ./vhost-switch -c 3 -n 2 --socket-mem 1024 --huge-dir /hugetlbfs -- -p
> 0x1 --dev-basename sock1

That means you were basing on the master branch. You should base on
next-virtio instead: http://dpdk.org/browse/next/dpdk-next-virtio/

> --switch "vmdq" --max-ports 3

Normally, we should keep the old behaviour first. Say, making the vmdq
as the default switch mode.

However, actually, I don't quite like to make the vhost-switch to bind
to a hardare feature that tightly, that you may want to make a standalone
patch as the last one in this patchset to make the "switch" mode be the
default one.

> 
> Signed-off-by: Pankaj Chauhan <pankaj.chauhan@nxp.com>
> ---
>  examples/vhost/main.c | 43 +++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 43 insertions(+)
> 
> diff --git a/examples/vhost/main.c b/examples/vhost/main.c
> index c949df4..a4e51ae 100644
> --- a/examples/vhost/main.c
> +++ b/examples/vhost/main.c
> @@ -142,6 +142,10 @@ static uint32_t burst_rx_retry_num = BURST_RX_RETRIES;
>  /* Character device basename. Can be set by user. */
>  static char dev_basename[MAX_BASENAME_SZ] = "vhost-net";
>  
> +/* vswitch device name and maximum number of ports */
> +static char switch_dev[MAX_BASENAME_SZ] = "vmdq";

First of all, limiting it with MAX_BASENAME_SZ makes no sense here.

Secondly, you don't have to represent the switch mode with string,
you could simply use some numeric macros, or enum.

Besides, I just had a quick glimplse of your patches (still couldn't
make a detailed look so far), and I'd ask you to do few more things
for v3:

- I'm hoping you could split this patchset further, say **maybe**
  one patch to introduce vswitch_port, one to introduce vswitch_ops
  and another one to introduce vswitch_dev. This helps review.

- make sure each commit is buldable.


And few more generic comments to the whole set:

- use "__rte_unused" but not "__attribute__((unused))"
  And we normally use it after but not before the key word.

- follow the DPDK prefered way to define a function, the return type
  and function name takes two lines.

- run scripts/{checkpatches.sh,check-git-log.sh} and fix real warnings
  if any before sending them out.

  This would at least help you catch "line over 80 chars" issue. 

Thanks.
	--yliu