On Thu, Oct 05, 2023 at 12:51:00PM +0100, Bruce Richardson wrote:
> The event structure in DPDK is 16-bytes in size, and events are
> regularly passed as parameters directly rather than being passed as
> pointers. To help compiler optimize correctly, we can explicitly request
> 16-byte alignment for events, which means that we should be able
> to do aligned vector loads/stores (e.g. with SSE or Neon) when working
> with those events.
>
> Signed-off-by: Bruce Richardson <bruce.richard...@intel.com>
> ---
> lib/eventdev/rte_eventdev.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/lib/eventdev/rte_eventdev.h b/lib/eventdev/rte_eventdev.h
> index 2ba8a7b090..bb0d59b059 100644
> --- a/lib/eventdev/rte_eventdev.h
> +++ b/lib/eventdev/rte_eventdev.h
> @@ -1344,7 +1344,7 @@ struct rte_event {
> struct rte_event_vector *vec;
> /**< Event vector pointer. */
> };
> -};
> +} __rte_aligned(16);
>
Looking for feedback on this idea - hence the fact this is going as an RFC.
It seems to me something that should be done for performance reasons, but
I'm not sure if there are any negative consequences of doing this.
Since this is an ABI-affecting change, a decision on this needs to be made
for 23.11, or else it will be locked in for at least another year. Hence me
sending it now as an RFC late in the release cycle, rather than deferring
to next release.
/Bruce
