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

[Bruce Richardson <bruce.richardson@intel.com>]

On Fri, Oct 06, 2023 at 03:54:26PM +0530, Jerin Jacob wrote:
> On Fri, Oct 6, 2023 at 3:49 PM Bruce Richardson
> <bruce.richardson@intel.com> wrote:
> >
> > On Fri, Oct 06, 2023 at 03:46:21PM +0530, Jerin Jacob wrote:
> > > On Fri, Oct 6, 2023 at 3:44 PM Morten Brørup <mb@smartsharesystems.com> wrote:
> > > >
> > > > > From: Bruce Richardson [mailto:bruce.richardson@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@intel.com>
> > > > > Acked-by: Morten Brørup <mb@smartsharesystems.com>
> > > > > Acked-by: Jerin Jacob <jerinj@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.
> > >
> > > Use existing RTE_BUILD_BUG_ON this on  .c file instead of header file.
> > >
> >
> > Ok to move to a C file, but I think using static_asserts are better than
> > using the old macro tricks of negatively sized arrays.
> 
> No strong opinion on the API. I just told because compatibility
> discussions came in.
> Key is to move to .c file.
> 
Thanks. V4 coming up....