[dpdk-dev] [PATCH] examples/l3fwd-power: fix Rx descriptor size

[Yao, Lei A]

I have test this patch based on 17.05-rc2 , issue is fixed. Host frequency can 
be changed according to the data throughput. 
Tested-by: Lei Yao (lei.a.yao at intel.com)

> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Pablo de Lara
> Sent: Wednesday, April 26, 2017 7:30 PM
> To: dev at dpdk.org
> Cc: De Lara Guarch, Pablo <pablo.de.lara.guarch at intel.com>;
> stable at dpdk.org
> Subject: [dpdk-dev] [PATCH] examples/l3fwd-power: fix Rx descriptor size
> 
> L3fwd power app monitors the RX queues to see if the polling frequency
> should be adjusted (the busier the queue, the higher the frequency).
> The app uses several thresholds in the ring to determine the frequency,
> being 96 the highest one, when frequency should be highest.
> 
> The problem is that the difference between this value and the ring size
> is not big enough (128 - 96 = 32 descriptors), which means that
> if the descriptors are not replenished quick enough, queue might
> not be busy, but the app would think that it is, because 96th descriptor
> is set.
> 
> Therefore, by increasing this gap (increasing the RX ring size),
> we make sure that this false measurement will not happen.
> 
> Fixes: b451aa39db31 ("examples/l3fwd-power: use DD bit rather than RX
> queue count")
> Cc: stable at dpdk.org
> 
> Signed-off-by: Pablo de Lara <pablo.de.lara.guarch at intel.com>
> ---
>  examples/l3fwd-power/main.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/examples/l3fwd-power/main.c b/examples/l3fwd-power/main.c
> index ec40a17..7a8e1cd 100644
> --- a/examples/l3fwd-power/main.c
> +++ b/examples/l3fwd-power/main.c
> @@ -147,7 +147,7 @@
>  /*
>   * Configurable number of RX/TX ring descriptors
>   */
> -#define RTE_TEST_RX_DESC_DEFAULT 128
> +#define RTE_TEST_RX_DESC_DEFAULT 512
>  #define RTE_TEST_TX_DESC_DEFAULT 512
>  static uint16_t nb_rxd = RTE_TEST_RX_DESC_DEFAULT;
>  static uint16_t nb_txd = RTE_TEST_TX_DESC_DEFAULT;
> --
> 2.7.4