[dpdk-dev] [PATCH] doc: announce adoption of C11 atomic operations semantics

[dpdk-dev] [PATCH] doc: announce adoption of C11 atomic operations semantics

[Phil Yang]

From: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>

As agreed in the DPDK tech board [1], after 20.05 release, patches must
use C11 atomic operations semantics with the help of wrappers.

[1] http://mails.dpdk.org/archives/dev/2020-April/165143.html

Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Reviewed-by: Phil Yang <phil.yang@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
---
 doc/guides/rel_notes/deprecation.rst | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
index 20aa745..208708d 100644
--- a/doc/guides/rel_notes/deprecation.rst
+++ b/doc/guides/rel_notes/deprecation.rst
@@ -113,3 +113,15 @@ Deprecation Notices
   Python 2 support will be completely removed in 20.11.
   In 20.08, explicit deprecation warnings will be displayed when running
   scripts with Python 2.
+
+* rte_atomicNN_xxx: These APIs do not take memory order parameter. This does
+  not allow for writing optimized code for all the CPU architectures supported
+  in DPDK. DPDK will adopt C11 atomic operations semantics and provide wrappers
+  using C11 atomic built-ins. These wrappers must be used for patches that
+  need to be merged in 20.08 onwards.
+
+* rte_smp_*mb: These APIs provide full barrier functionality. However, many
+  use cases do not require full barriers. To support such use cases, DPDK will
+  adopt C11 barrier semantics and provide wrappers using C11 atomic built-ins.
+  These wrappers must be used for patches that need to be merged in 20.08
+  onwards.
-- 
2.7.4

Re: [dpdk-dev] [PATCH] doc: announce adoption of C11 atomic operations semantics

[Stephen Hemminger]

On Thu,  7 May 2020 15:06:33 +0800
Phil Yang <phil.yang@arm.com> wrote:

> From: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> 
> As agreed in the DPDK tech board [1], after 20.05 release, patches must
> use C11 atomic operations semantics with the help of wrappers.
> 
> [1] http://mails.dpdk.org/archives/dev/2020-April/165143.html
> 
> Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> Reviewed-by: Phil Yang <phil.yang@arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>

The use of Gcc __sync_ primitives should also be replaced with C11 atomic.

Re: [dpdk-dev] [PATCH] doc: announce adoption of C11 atomic operations semantics

[Honnappa Nagarahalli]

<snip>

> Subject: Re: [PATCH] doc: announce adoption of C11 atomic operations
> semantics
> 
> On Thu,  7 May 2020 15:06:33 +0800
> Phil Yang <phil.yang@arm.com> wrote:
> 
> > From: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> >
> > As agreed in the DPDK tech board [1], after 20.05 release, patches
> > must use C11 atomic operations semantics with the help of wrappers.
> >
> > [1] http://mails.dpdk.org/archives/dev/2020-April/165143.html
> >
> > Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> > Reviewed-by: Phil Yang <phil.yang@arm.com>
> > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> 
> The use of Gcc __sync_ primitives should also be replaced with C11 atomic.
Agree, not sure if this should be added to the deprecation list. But, will add it to checkpatches.sh

Re: [dpdk-dev] [PATCH] doc: announce adoption of C11 atomic operations semantics

[Honnappa Nagarahalli]

<snip>

> Subject: [PATCH] doc: announce adoption of C11 atomic operations semantics
> 
> From: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> 
> As agreed in the DPDK tech board [1], after 20.05 release, patches must use
> C11 atomic operations semantics with the help of wrappers.
> 
> [1] http://mails.dpdk.org/archives/dev/2020-April/165143.html
As noted in the minutes, this has been approved in the tech-board. Can I get some ACKs for this patch?

> 
> Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> Reviewed-by: Phil Yang <phil.yang@arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> ---
>  doc/guides/rel_notes/deprecation.rst | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/doc/guides/rel_notes/deprecation.rst
> b/doc/guides/rel_notes/deprecation.rst
> index 20aa745..208708d 100644
> --- a/doc/guides/rel_notes/deprecation.rst
> +++ b/doc/guides/rel_notes/deprecation.rst
> @@ -113,3 +113,15 @@ Deprecation Notices
>    Python 2 support will be completely removed in 20.11.
>    In 20.08, explicit deprecation warnings will be displayed when running
>    scripts with Python 2.
> +
> +* rte_atomicNN_xxx: These APIs do not take memory order parameter. This
> +does
> +  not allow for writing optimized code for all the CPU architectures
> +supported
> +  in DPDK. DPDK will adopt C11 atomic operations semantics and provide
> +wrappers
> +  using C11 atomic built-ins. These wrappers must be used for patches
> +that
> +  need to be merged in 20.08 onwards.
> +
> +* rte_smp_*mb: These APIs provide full barrier functionality. However,
> +many
> +  use cases do not require full barriers. To support such use cases,
> +DPDK will
> +  adopt C11 barrier semantics and provide wrappers using C11 atomic built-
> ins.
> +  These wrappers must be used for patches that need to be merged in
> +20.08
> +  onwards.
> --
> 2.7.4

Re: [dpdk-dev] [PATCH] doc: announce adoption of C11 atomic operations semantics

[Hemant Agrawal]

Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>

Re: [dpdk-dev] [PATCH] doc: announce adoption of C11 atomic operations semantics

[Jerin Jacob]

On Thu, May 7, 2020 at 12:38 PM Phil Yang <phil.yang@arm.com> wrote:
>
> From: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
>
> As agreed in the DPDK tech board [1], after 20.05 release, patches must
> use C11 atomic operations semantics with the help of wrappers.
>
> [1] http://mails.dpdk.org/archives/dev/2020-April/165143.html
>
> Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> Reviewed-by: Phil Yang <phil.yang@arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>


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



> ---
>  doc/guides/rel_notes/deprecation.rst | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
>
> diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
> index 20aa745..208708d 100644
> --- a/doc/guides/rel_notes/deprecation.rst
> +++ b/doc/guides/rel_notes/deprecation.rst
> @@ -113,3 +113,15 @@ Deprecation Notices
>    Python 2 support will be completely removed in 20.11.
>    In 20.08, explicit deprecation warnings will be displayed when running
>    scripts with Python 2.
> +
> +* rte_atomicNN_xxx: These APIs do not take memory order parameter. This does
> +  not allow for writing optimized code for all the CPU architectures supported
> +  in DPDK. DPDK will adopt C11 atomic operations semantics and provide wrappers
> +  using C11 atomic built-ins. These wrappers must be used for patches that
> +  need to be merged in 20.08 onwards.
> +
> +* rte_smp_*mb: These APIs provide full barrier functionality. However, many
> +  use cases do not require full barriers. To support such use cases, DPDK will
> +  adopt C11 barrier semantics and provide wrappers using C11 atomic built-ins.
> +  These wrappers must be used for patches that need to be merged in 20.08
> +  onwards.
> --
> 2.7.4
>

Re: [dpdk-dev] [PATCH] doc: announce adoption of C11 atomic operations semantics

[Ananyev, Konstantin]

> >
> > As agreed in the DPDK tech board [1], after 20.05 release, patches must
> > use C11 atomic operations semantics with the help of wrappers.
> >
> > [1] http://mails.dpdk.org/archives/dev/2020-April/165143.html
> >
> > Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> > Reviewed-by: Phil Yang <phil.yang@arm.com>
> > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> 
> > ---
> >  doc/guides/rel_notes/deprecation.rst | 12 ++++++++++++
> >  1 file changed, 12 insertions(+)
> >
> > diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
> > index 20aa745..208708d 100644
> > --- a/doc/guides/rel_notes/deprecation.rst
> > +++ b/doc/guides/rel_notes/deprecation.rst
> > @@ -113,3 +113,15 @@ Deprecation Notices
> >    Python 2 support will be completely removed in 20.11.
> >    In 20.08, explicit deprecation warnings will be displayed when running
> >    scripts with Python 2.
> > +
> > +* rte_atomicNN_xxx: These APIs do not take memory order parameter. This does
> > +  not allow for writing optimized code for all the CPU architectures supported
> > +  in DPDK. DPDK will adopt C11 atomic operations semantics and provide wrappers
> > +  using C11 atomic built-ins. These wrappers must be used for patches that
> > +  need to be merged in 20.08 onwards.
> > +
> > +* rte_smp_*mb: These APIs provide full barrier functionality. However, many
> > +  use cases do not require full barriers. To support such use cases, DPDK will
> > +  adopt C11 barrier semantics and provide wrappers using C11 atomic built-ins.
> > +  These wrappers must be used for patches that need to be merged in 20.08
> > +  onwards.
> > --

Can we probably add a note that new API supposed to not introduce
performance degradation comparing to one we are going to deprecate?
Thanks
Konstantin

Re: [dpdk-dev] [PATCH] doc: announce adoption of C11 atomic operations semantics

[David Christensen]

On 5/7/20 12:06 AM, Phil Yang wrote:
> From: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> 
> As agreed in the DPDK tech board [1], after 20.05 release, patches must
> use C11 atomic operations semantics with the help of wrappers.
> 
> [1] http://mails.dpdk.org/archives/dev/2020-April/165143.html
> 
> Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> Reviewed-by: Phil Yang <phil.yang@arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>

Acked-by: David Christensen <drc@linux.vnet.ibm.com>

[dpdk-dev] [PATCH v2] doc: announce adoption of C11 atomic operations semantics

[Honnappa Nagarahalli]

As agreed in the DPDK tech board [1], after 20.05 release, patches must
use C11 atomic operations semantics with the help of wrappers.

[1] http://mails.dpdk.org/archives/dev/2020-April/165143.html

Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Reviewed-by: Phil Yang <phil.yang@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>
Acked-by: Jerin Jacob <jerinj@marvell.com>
---
 doc/guides/rel_notes/deprecation.rst | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
index 20aa745b7..01f99a0d6 100644
--- a/doc/guides/rel_notes/deprecation.rst
+++ b/doc/guides/rel_notes/deprecation.rst
@@ -113,3 +113,16 @@ Deprecation Notices
   Python 2 support will be completely removed in 20.11.
   In 20.08, explicit deprecation warnings will be displayed when running
   scripts with Python 2.
+
+* rte_atomicNN_xxx: These APIs do not take memory order parameter. This does
+  not allow for writing optimized code for all the CPU architectures supported
+  in DPDK. DPDK will adopt C11 atomic operations semantics and provide wrappers
+  using C11 atomic built-ins. These wrappers must be used for patches that
+  need to be merged in 20.08 onwards. This change will not introduce any
+  performance degradation.
+
+* rte_smp_*mb: These APIs provide full barrier functionality. However, many
+  use cases do not require full barriers. To support such use cases, DPDK will
+  adopt C11 barrier semantics and provide wrappers using C11 atomic built-ins.
+  These wrappers must be used for patches that need to be merged in 20.08
+  onwards. This change will not introduce any performance degradation.
-- 
2.17.1

Re: [dpdk-dev] [PATCH v2] doc: announce adoption of C11 atomic operations semantics

[Ananyev, Konstantin]

> 
> As agreed in the DPDK tech board [1], after 20.05 release, patches must
> use C11 atomic operations semantics with the help of wrappers.
> 
> [1] http://mails.dpdk.org/archives/dev/2020-April/165143.html
> 
> Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> Reviewed-by: Phil Yang <phil.yang@arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>
> Acked-by: Jerin Jacob <jerinj@marvell.com>
> ---
>  doc/guides/rel_notes/deprecation.rst | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
> index 20aa745b7..01f99a0d6 100644
> --- a/doc/guides/rel_notes/deprecation.rst
> +++ b/doc/guides/rel_notes/deprecation.rst
> @@ -113,3 +113,16 @@ Deprecation Notices
>    Python 2 support will be completely removed in 20.11.
>    In 20.08, explicit deprecation warnings will be displayed when running
>    scripts with Python 2.
> +
> +* rte_atomicNN_xxx: These APIs do not take memory order parameter. This does
> +  not allow for writing optimized code for all the CPU architectures supported
> +  in DPDK. DPDK will adopt C11 atomic operations semantics and provide wrappers
> +  using C11 atomic built-ins. These wrappers must be used for patches that
> +  need to be merged in 20.08 onwards. This change will not introduce any
> +  performance degradation.
> +
> +* rte_smp_*mb: These APIs provide full barrier functionality. However, many
> +  use cases do not require full barriers. To support such use cases, DPDK will
> +  adopt C11 barrier semantics and provide wrappers using C11 atomic built-ins.
> +  These wrappers must be used for patches that need to be merged in 20.08
> +  onwards. This change will not introduce any performance degradation.
> --

Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>

> 2.17.1

Re: [dpdk-dev] [PATCH v2] doc: announce adoption of C11 atomic operations semantics

[Thomas Monjalon]

> > As agreed in the DPDK tech board [1], after 20.05 release, patches must
> > use C11 atomic operations semantics with the help of wrappers.
> > 
> > [1] http://mails.dpdk.org/archives/dev/2020-April/165143.html
> > 
> > Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> > Reviewed-by: Phil Yang <phil.yang@arm.com>
> > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>
> > Acked-by: Jerin Jacob <jerinj@marvell.com>
> > ---
> > +* rte_atomicNN_xxx: These APIs do not take memory order parameter. This does
> > +  not allow for writing optimized code for all the CPU architectures supported
> > +  in DPDK. DPDK will adopt C11 atomic operations semantics and provide wrappers
> > +  using C11 atomic built-ins. These wrappers must be used for patches that
> > +  need to be merged in 20.08 onwards. This change will not introduce any
> > +  performance degradation.
> > +
> > +* rte_smp_*mb: These APIs provide full barrier functionality. However, many
> > +  use cases do not require full barriers. To support such use cases, DPDK will
> > +  adopt C11 barrier semantics and provide wrappers using C11 atomic built-ins.
> > +  These wrappers must be used for patches that need to be merged in 20.08
> > +  onwards. This change will not introduce any performance degradation.
> 
> Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
Acked-by: David Christensen <drc@linux.vnet.ibm.com>

Applied, thanks