From: "Morten Brørup" <mb@smartsharesystems.com>
To: "Bruce Richardson" <bruce.richardson@intel.com>
Cc: <dev@dpdk.org>, "Jerin Jacob" <jerinj@marvell.com>
Subject: RE: [PATCH v3] eventdev: ensure 16-byte alignment for events
Date: Fri, 6 Oct 2023 12:35:26 +0200 [thread overview]
Message-ID: <98CBD80474FA8B44BF855DF32C47DC35E9EF04@smartserver.smartshare.dk> (raw)
In-Reply-To: <ZR/eiGbbJB1VL2dA@bricha3-MOBL.ger.corp.intel.com>
> From: Bruce Richardson [mailto:bruce.richardson@intel.com]
> Sent: Friday, 6 October 2023 12.17
ev: ensure 16-byte alignment for events
>
> On Fri, Oct 06, 2023 at 12:13:54PM +0200, Morten Brørup 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.
> >
> > 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?
Yes, the link mentions "static_assert" being available for C11 as a convenience macro in assert.h.
I had to read the link very carefully to get this. I guess I'm not the only one. :-)
I don't object to moving it to the .c file. However, I think it's convenient for readability to have the static_assert close to the thing it checks, and/or close to any code that relies on the assumption it checks.
next prev parent reply other threads:[~2023-10-06 10:35 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-05 11:51 [RFC PATCH] " Bruce Richardson
2023-10-05 12:06 ` Bruce Richardson
2023-10-05 13:11 ` Jerin Jacob
2023-10-05 13:15 ` Bruce Richardson
2023-10-06 7:19 ` Jerin Jacob
2023-10-05 12:12 ` Morten Brørup
2023-10-05 13:02 ` Bruce Richardson
2023-10-06 9:37 ` [PATCH v2] " Bruce Richardson
2023-10-06 9:45 ` [PATCH v3] " Bruce Richardson
2023-10-06 10:13 ` Morten Brørup
2023-10-06 10:16 ` Jerin Jacob
2023-10-06 10:19 ` Bruce Richardson
2023-10-06 10:24 ` Jerin Jacob
2023-10-06 10:27 ` Bruce Richardson
2023-10-06 10:16 ` Bruce Richardson
2023-10-06 10:35 ` Morten Brørup [this message]
2023-10-06 10:44 ` Bruce Richardson
2023-10-06 10:29 ` [PATCH v4] " Bruce Richardson
2023-11-12 0:01 ` Stephen Hemminger
2023-11-12 8:30 ` Morten Brørup
2023-11-12 23:31 ` Stephen Hemminger
2023-11-13 7:58 ` Morten Brørup
2024-01-19 21:05 ` Tyler Retzlaff
2023-10-06 12:15 ` [RFC PATCH] " Mattias Rönnblom
2023-10-06 12:19 ` Bruce Richardson
2023-10-06 12:29 ` Mattias Rönnblom
2024-01-19 22:30 ` Stephen Hemminger
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