Re: [dpdk-dev] [PATCH] igb: change default RX wthresh back

["Ananyev, Konstantin" <konstantin.ananyev@intel.com>]

Hi Wenzhuo,
> 
> A problem is found on i350 VF. TX will happen once per 4
> packets. If only 1~3 packets are received, they will not be
> forwarded.
> 
> The reason is the default RX write-back threshold is changed
> to 4. This patch changes the value back to 0, so every packet
> can be handled immediately.
> 
> Fixes: 4a41c17dba18 (igb: set default thresholds based on MAC type)
> Signed-off-by: Wenzhuo Lu <wenzhuo.lu@intel.com>
> ---
>  drivers/net/e1000/igb_ethdev.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/e1000/igb_ethdev.c b/drivers/net/e1000/igb_ethdev.c
> index bd0ae26..34120ae 100644
> --- a/drivers/net/e1000/igb_ethdev.c
> +++ b/drivers/net/e1000/igb_ethdev.c
> @@ -64,7 +64,7 @@
> 
>  #define IGB_DEFAULT_RX_PTHRESH      ((hw->mac.type == e1000_i354) ? 12 : 8)
>  #define IGB_DEFAULT_RX_HTHRESH      8
> -#define IGB_DEFAULT_RX_WTHRESH      ((hw->mac.type == e1000_82576) ? 1 : 4)
> +#define IGB_DEFAULT_RX_WTHRESH      0

But that still doesn't prevent user from setting wthresh to whatever he likes inside
rx_queue_setup(), so the problem persists right?
As a side notice, it seems really bad practice to use implicit variables inside macro definition. 
Konstantin

> 
>  #define IGB_DEFAULT_TX_PTHRESH      ((hw->mac.type == e1000_i354) ? 20 : 8)
>  #define IGB_DEFAULT_TX_HTHRESH      1
> --
> 1.9.3