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