Re: [dpdk-dev] [PATCH v3 2/2] net/mlx4: avoid constant recreations in functions

[Shahaf Shuler <shahafs@mellanox.com>]

Thursday, May 10, 2018 5:22 PM, Ophir Munk:
> Subject: [PATCH v3 2/2] net/mlx4: avoid constant recreations in functions
> 
> Functions mlx4_ibv_to_rss_types() and mlx4_conv_rss_types() contain
> constant arrays variables which are recreated with every call to the functions.
> By changing the arrays definitions from "const" to "static const"
> these recreations can be saved.
> 
> Signed-off-by: Ophir Munk <ophirmu@mellanox.com>
> ---
>  drivers/net/mlx4/mlx4_flow.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/mlx4/mlx4_flow.c b/drivers/net/mlx4/mlx4_flow.c
> index baad299..6e9b81e 100644
> --- a/drivers/net/mlx4/mlx4_flow.c
> +++ b/drivers/net/mlx4/mlx4_flow.c
> @@ -91,7 +91,7 @@ uint64_t
>  mlx4_conv_rss_types(struct priv *priv, uint64_t types)  {
>  	enum { IPV4, IPV6, TCP, UDP, };
> -	const uint64_t in[] = {
> +	static const uint64_t in[] = {
>  		[IPV4] = (ETH_RSS_IPV4 |
>  			  ETH_RSS_FRAG_IPV4 |
>  			  ETH_RSS_NONFRAG_IPV4_TCP |
> @@ -112,7 +112,7 @@ mlx4_conv_rss_types(struct priv *priv, uint64_t
> types)
>  			 ETH_RSS_NONFRAG_IPV6_UDP |
>  			 ETH_RSS_IPV6_UDP_EX),
>  	};
> -	const uint64_t out[RTE_DIM(in)] = {
> +	static const uint64_t out[RTE_DIM(in)] = {

Since there is another version, it is better to have this patch first with the above fixes.

>  		[IPV4] = IBV_RX_HASH_SRC_IPV4 |
> IBV_RX_HASH_DST_IPV4,
>  		[IPV6] = IBV_RX_HASH_SRC_IPV6 |
> IBV_RX_HASH_DST_IPV6,
>  		[TCP] = IBV_RX_HASH_SRC_PORT_TCP |
> IBV_RX_HASH_DST_PORT_TCP, @@ -153,7 +153,7 @@
> mlx4_ibv_to_rss_types(uint64_t types)  {
>  	enum { IPV4, IPV6, IPV4_TCP, IPV6_TCP, IPV4_UDP, IPV6_UDP};
> 
> -	const uint64_t in[] = {
> +	static const uint64_t in[] = {

And this one can be done as part of the "advertise supported RSS ..." commit. 

It is better to have the fix/clean patch first, and then to introduce the new code. 

>  		[IPV4] = IPV4_IBV_HF,
>  		[IPV6] = IPV6_IBV_HF,
>  		[IPV4_TCP] = IPV4_IBV_HF | TCP_IBV_HF, @@ -161,7 +161,7
> @@ mlx4_ibv_to_rss_types(uint64_t types)
>  		[IPV4_UDP] = IPV4_IBV_HF | UDP_IBV_HF,
>  		[IPV6_UDP] = IPV6_IBV_HF | UDP_IBV_HF,
>  	};
> -	const uint64_t out[RTE_DIM(in)] = {
> +	static const uint64_t out[RTE_DIM(in)] = {
>  		[IPV4] = IPV4_RSS_HF,
>  		[IPV6] = IPV6_RSS_HF,
>  		[IPV4_TCP] = IPV4_RSS_HF | IPV4_TCP_RSS_HF,
> --
> 2.7.4