[v4,2/3] doc: update armv8-a IO barrier changes

Message ID 20200706234333.26310-2-honnappa.nagarahalli@arm.com
State New
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Series
  • [v4,1/3] eal: adjust barriers for IO on Armv8-a
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Commit Message

Honnappa Nagarahalli July 6, 2020, 11:43 p.m.
Updated the use of DMB instruction in rte_*mb APIs for Armv8-a.

Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>

Acked-by: Jerin Jacob <jerinj@marvell.com>

---
 doc/guides/rel_notes/release_20_08.rst | 7 +++++++
 1 file changed, 7 insertions(+)

-- 
2.17.1

Comments

David Marchand July 7, 2020, 8:36 a.m. | #1
On Tue, Jul 7, 2020 at 1:44 AM Honnappa Nagarahalli
<honnappa.nagarahalli@arm.com> wrote:
>

> Updated the use of DMB instruction in rte_*mb APIs for Armv8-a.

>

> Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>

> Acked-by: Jerin Jacob <jerinj@marvell.com>

> ---

>  doc/guides/rel_notes/release_20_08.rst | 7 +++++++

>  1 file changed, 7 insertions(+)

>

> diff --git a/doc/guides/rel_notes/release_20_08.rst b/doc/guides/rel_notes/release_20_08.rst

> index 5cbc4ce14..567ae6b2a 100644

> --- a/doc/guides/rel_notes/release_20_08.rst

> +++ b/doc/guides/rel_notes/release_20_08.rst

> @@ -56,6 +56,13 @@ New Features

>       Also, make sure to start the actual text at the margin.

>       =========================================================

>


This release note update will be squashed with the change itself in patch 1.

> +* **rte_*mb APIs are updated to use DMB instruction for Armv8-a.**


We use "ARMv8" in the release notes, any objection if I update this
when applying?


> +

> +  Armv8-a memory model has been strengthened to require other-multi-copy

> +  atomicity. This allows for using DMB instruction instead of DSB for IO

> +  barriers. rte_*mb APIs, for Armv8-a platforms, are changed to use DMB

> +  instruction to reflect this.

> +

>  * **Updated PCAP driver.**

>

>    Updated PCAP driver with new features and improvements, including:

> --

> 2.17.1

>



-- 
David Marchand
Honnappa Nagarahalli July 7, 2020, 6:37 p.m. | #2
<snip>

> Subject: Re: [dpdk-dev] [PATCH v4 2/3] doc: update armv8-a IO barrier

> changes

> 

> On Tue, Jul 7, 2020 at 1:44 AM Honnappa Nagarahalli

> <honnappa.nagarahalli@arm.com> wrote:

> >

> > Updated the use of DMB instruction in rte_*mb APIs for Armv8-a.

> >

> > Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>

> > Acked-by: Jerin Jacob <jerinj@marvell.com>

> > ---

> >  doc/guides/rel_notes/release_20_08.rst | 7 +++++++

> >  1 file changed, 7 insertions(+)

> >

> > diff --git a/doc/guides/rel_notes/release_20_08.rst

> > b/doc/guides/rel_notes/release_20_08.rst

> > index 5cbc4ce14..567ae6b2a 100644

> > --- a/doc/guides/rel_notes/release_20_08.rst

> > +++ b/doc/guides/rel_notes/release_20_08.rst

> > @@ -56,6 +56,13 @@ New Features

> >       Also, make sure to start the actual text at the margin.

> >       =========================================================

> >

> 

> This release note update will be squashed with the change itself in patch 1.

> 

> > +* **rte_*mb APIs are updated to use DMB instruction for Armv8-a.**

> 

> We use "ARMv8" in the release notes, any objection if I update this when

> applying?

No objections.

> 

> 

> > +

> > +  Armv8-a memory model has been strengthened to require

> > + other-multi-copy  atomicity. This allows for using DMB instruction

> > + instead of DSB for IO  barriers. rte_*mb APIs, for Armv8-a

> > + platforms, are changed to use DMB  instruction to reflect this.

> > +

> >  * **Updated PCAP driver.**

> >

> >    Updated PCAP driver with new features and improvements, including:

> > --

> > 2.17.1

> >

> 

> 

> --

> David Marchand

Patch

diff --git a/doc/guides/rel_notes/release_20_08.rst b/doc/guides/rel_notes/release_20_08.rst
index 5cbc4ce14..567ae6b2a 100644
--- a/doc/guides/rel_notes/release_20_08.rst
+++ b/doc/guides/rel_notes/release_20_08.rst
@@ -56,6 +56,13 @@  New Features
      Also, make sure to start the actual text at the margin.
      =========================================================
 
+* **rte_*mb APIs are updated to use DMB instruction for Armv8-a.**
+
+  Armv8-a memory model has been strengthened to require other-multi-copy
+  atomicity. This allows for using DMB instruction instead of DSB for IO
+  barriers. rte_*mb APIs, for Armv8-a platforms, are changed to use DMB
+  instruction to reflect this.
+
 * **Updated PCAP driver.**
 
   Updated PCAP driver with new features and improvements, including: