Re: [dpdk-dev] [PATCH] examples/vhost: change the default value of NIC's max queues

["Xia, Chenbo" <chenbo.xia@intel.com>]

Hi Wenwu,

> -----Original Message-----
> From: Ma, WenwuX <wenwux.ma@intel.com>
> Sent: Friday, September 10, 2021 9:52 PM
> To: dev@dpdk.org
> Cc: maxime.coquelin@redhat.com; Xia, Chenbo <chenbo.xia@intel.com>; Jiang,
> Cheng1 <cheng1.jiang@intel.com>; Hu, Jiayu <jiayu.hu@intel.com>; Wang, Yinan
> <yinan.wang@intel.com>; Ma, WenwuX <wenwux.ma@intel.com>
> Subject: [PATCH] examples/vhost: change the default value of NIC's max queues
> 
> vswitch can't launch with 40G FTV due to Device start fails

Not many people can understand what's FTV. So let's describe it with a driver
name. Example if it's 'i40e':

vswitch can't launch with a 40G i40e port...

And Device -> device

> if NIC’s max queues > the default number of 128,
> so, we changed the default value from 128 to 512.
>

I'd say it's not cool to still hard-code the MAX_QUEUES so that only 'some' NICs
can work with the example. The app should have a way to check this kind of info 
before init/start. But as I would like to see at some point, this example will
be removed and all our tests go to testpmd. Let's not waste too much effort on
this example.

Besides: it can be a fix. Let's backport it.

Thanks,
Chenbo
 
> Signed-off-by: Wenwu Ma <wenwux.ma@intel.com>
> ---
>  examples/vhost/main.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/examples/vhost/main.c b/examples/vhost/main.c
> index bc3d71c898..36969a4de5 100644
> --- a/examples/vhost/main.c
> +++ b/examples/vhost/main.c
> @@ -29,7 +29,7 @@
>  #include "main.h"
> 
>  #ifndef MAX_QUEUES
> -#define MAX_QUEUES 128
> +#define MAX_QUEUES 512
>  #endif
> 
>  /* the maximum number of external ports supported */
> --
> 2.25.1