[PATCH v3] eventdev: ensure 16-byte alignment for events

[Bruce Richardson]

On Fri, Oct 06, 2023 at 12:13:54PM +0200, Morten Brørup wrote:
> > From: Bruce Richardson [mailto:bruce.richardson at intel.com]
> > Sent: Friday, 6 October 2023 11.45
> > 
> > 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.richardson at intel.com>
> > Acked-by: Morten Brørup <mb at smartsharesystems.com>
> > Acked-by: Jerin Jacob <jerinj at marvell.com>
> > 
> > ---
> 
> [...]
> 
> > +_Static_assert(sizeof(struct rte_event) == 16, "Event structure size is not 16-bytes in size");
> 
> Thank you for adding this extra check. We should have more of these.
> 
> NB: _Static_assert is deprecated in C23 [1], so for forward compatibility, you could use static_assert (which is available in <assert.h>) instead. Nice to have; feel free to ignore this comment.
> 
Is the availability in assert.h backward compatible with C11, since the
link you posted seems to imply that "static_assert" is only from C23
onwards?