Re: [dpdk-dev] [PATCH v2] ethdev: make ethdev data cache aligned

[Matan Azrad <matan@mellanox.com>]

Hi Jerin

 From: Jerin Jacob [mailto:jerin.jacob@caviumnetworks.com]
> Since struct rte_eth_dev_data used in the fast path, making it as cache
> aligned.
> 
> Fixes: af75078fece3 ("first public release")
> Fixes: 5b7ba31148a8 ("ethdev: add port ownership")

Looks like it is just improvement.
No need the above "fixes" lines (also fix title is not needed as you did).

I think that performance improvement results should be added to the commit log.

Moreover, Did you investigate which fields in rte_eth_dev_data structures are important for performance and should not be in a different cache lines?
Maybe alternative order of the fields in the structure may improve the performance more... 
 
> Cc: Matan Azrad <matan@mellanox.com>
> Cc: Thomas Monjalon <thomas@monjalon.net>
> Cc: Konstantin Ananyev <konstantin.ananyev@intel.com>
> 
> Signed-off-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>
> Signed-off-by: Pavan Nikhilesh <pbhagavatula@caviumnetworks.com>
> ---
> v2:
> - Change the git comments based on Matan's feedback
> https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdp
> dk.org%2Fdev%2Fpatchwork%2Fpatch%2F35104%2F&data=02%7C01%7Cmat
> an%40mellanox.com%7C5c2537b12e6d4e51f12a08d571dd33a2%7Ca652971c7
> d2e4d9ba6a4d149256f461b%7C0%7C0%7C636540117238324576&sdata=8OOg
> Zb0KzDbBce9xPVywV8ynmiKP9B%2BbYsQxgE5VlX0%3D&reserved=0
> 
> - Some platform like thunderx + l3fwd showed 1% regression in the
> performance with 5b7ba31148a8 ("ethdev: add port ownership") in one port
> setup.
> 
> - If there are no objection for this change then request to take it for v18.02
> release.
> ---
>  lib/librte_ether/rte_ethdev_core.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/lib/librte_ether/rte_ethdev_core.h
> b/lib/librte_ether/rte_ethdev_core.h
> index 315b31723..e5681e466 100644
> --- a/lib/librte_ether/rte_ethdev_core.h
> +++ b/lib/librte_ether/rte_ethdev_core.h
> @@ -601,7 +601,7 @@ struct rte_eth_dev_data {
>  	struct rte_vlan_filter_conf vlan_filter_conf;
>  	/**< VLAN filter configuration. */
>  	struct rte_eth_dev_owner owner; /**< The port owner. */ -};
> +} __rte_cache_aligned;
> 
>  /**
>   * @internal
> --
> 2.16.1