[v5,2/3] config/arm: add support for fallback march
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Commit Message
From: Pavan Nikhilesh <pbhagavatula@marvell.com>
Some ARM CPUs have specific march requirements and
are not compatible with the supported march list.
Add fallback march in case the mcpu and the march
advertised in the part_number_config are not supported
by the compiler.
Example
mcpu = neoverse-n2
march = armv9-a
fallback_march = armv8.5-a
mcpu, march not supported
machine_args = ['-march=armv8.5-a']
mcpu, march, fallback_march not supported
least march supported = armv8-a
machine_args = ['-march=armv8-a']
Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
---
config/arm/meson.build | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
Comments
On Thu, Feb 22, 2024 at 1:45 PM <pbhagavatula@marvell.com> wrote:
>
> From: Pavan Nikhilesh <pbhagavatula@marvell.com>
>
> Some ARM CPUs have specific march requirements and
> are not compatible with the supported march list.
> Add fallback march in case the mcpu and the march
> advertised in the part_number_config are not supported
> by the compiler.
>
> Example
> mcpu = neoverse-n2
> march = armv9-a
> fallback_march = armv8.5-a
>
> mcpu, march not supported
> machine_args = ['-march=armv8.5-a']
>
> mcpu, march, fallback_march not supported
> least march supported = armv8-a
>
> machine_args = ['-march=armv8-a']
>
> Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
> ---
> config/arm/meson.build | 14 +++++++++++---
> 1 file changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/config/arm/meson.build b/config/arm/meson.build
> index d05d54b564..87ff5039f6 100644
> --- a/config/arm/meson.build
> +++ b/config/arm/meson.build
> @@ -94,6 +94,7 @@ part_number_config_arm = {
> '0xd49': {
> 'march': 'armv9-a',
> 'march_features': ['sve2'],
> + 'fallback_march': 'armv8.5-a',
> 'mcpu': 'neoverse-n2',
> 'flags': [
> ['RTE_MACHINE', '"neoverse-n2"'],
> @@ -708,6 +709,7 @@ if update_flags
>
> candidate_mcpu = ''
> candidate_march = ''
> + fallback_march = ''
>
> if part_number_config.has_key('mcpu') and
> cc.has_argument('-mcpu=' + part_number_config['mcpu'])
> @@ -736,16 +738,22 @@ if update_flags
> # start checking from this version downwards
> check_compiler_support = true
> endif
> - if (check_compiler_support and
> + if (check_compiler_support and candidate_march == '' and
> cc.has_argument('-march=' + supported_march))
> candidate_march = supported_march
> - # highest supported march version found
> - break
> + endif
> + if (part_number_config.has_key('fallback_march') and
> + supported_march == part_number_config['fallback_march'] and
> + cc.has_argument('-march=' + supported_march))
> + fallback_march = supported_march
If both fallback_march and march are supported, fallback_march is
going to be chosen over march. I think this is what we want instead:
Use march if supported,
then use fallback_march if supported,
then use the other fallback marchs.
If the above is indeed what we want, we could just put this after
endforeach (in the original version):
# at this point, candidate march is either
part_number_config['fallback_march'] or some other lower version
if (part_number_config.has_key('fallback_march') and
candidate_march != part_number_config['march'] and
cc.has_argument('-march=' + part_number_config['fallback_march']))
# this overwrites only the lower version with preferred
fallback_march, if supported
candidate_march = part_number_config['fallback_march']
endif
This way we won't even need the fallback_march variable.
> endif
> endforeach
> endif
>
> if candidate_march != part_number_config['march']
> + if fallback_march != ''
> + candidate_march = fallback_march
> + endif
> warning('Configuration march version is @0@, not supported.'
> .format(part_number_config['march']))
> if candidate_march != ''
> --
> 2.25.1
>
> On Thu, Feb 22, 2024 at 1:45 PM <pbhagavatula@marvell.com> wrote:
> >
> > From: Pavan Nikhilesh <pbhagavatula@marvell.com>
> >
> > Some ARM CPUs have specific march requirements and
> > are not compatible with the supported march list.
> > Add fallback march in case the mcpu and the march
> > advertised in the part_number_config are not supported
> > by the compiler.
> >
> > Example
> > mcpu = neoverse-n2
> > march = armv9-a
> > fallback_march = armv8.5-a
> >
> > mcpu, march not supported
> > machine_args = ['-march=armv8.5-a']
> >
> > mcpu, march, fallback_march not supported
> > least march supported = armv8-a
> >
> > machine_args = ['-march=armv8-a']
> >
> > Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
> > ---
> > config/arm/meson.build | 14 +++++++++++---
> > 1 file changed, 11 insertions(+), 3 deletions(-)
> >
> > diff --git a/config/arm/meson.build b/config/arm/meson.build
> > index d05d54b564..87ff5039f6 100644
> > --- a/config/arm/meson.build
> > +++ b/config/arm/meson.build
> > @@ -94,6 +94,7 @@ part_number_config_arm = {
> > '0xd49': {
> > 'march': 'armv9-a',
> > 'march_features': ['sve2'],
> > + 'fallback_march': 'armv8.5-a',
> > 'mcpu': 'neoverse-n2',
> > 'flags': [
> > ['RTE_MACHINE', '"neoverse-n2"'],
> > @@ -708,6 +709,7 @@ if update_flags
> >
> > candidate_mcpu = ''
> > candidate_march = ''
> > + fallback_march = ''
> >
> > if part_number_config.has_key('mcpu') and
> > cc.has_argument('-mcpu=' + part_number_config['mcpu'])
> > @@ -736,16 +738,22 @@ if update_flags
> > # start checking from this version downwards
> > check_compiler_support = true
> > endif
> > - if (check_compiler_support and
> > + if (check_compiler_support and candidate_march == '' and
> > cc.has_argument('-march=' + supported_march))
> > candidate_march = supported_march
> > - # highest supported march version found
> > - break
> > + endif
> > + if (part_number_config.has_key('fallback_march') and
> > + supported_march == part_number_config['fallback_march'] and
> > + cc.has_argument('-march=' + supported_march))
> > + fallback_march = supported_march
>
> If both fallback_march and march are supported, fallback_march is
> going to be chosen over march.
The current flow still chooses the march
Message: Arm implementer: Arm
Message: Arm part number: 0xd49
Compiler for C supports arguments -march=armv9-a: YES
Compiler for C supports arguments -march=armv8.5-a: YES
Compiler for C supports arguments -march=armv9-a+sve2: YES
Compiler for C supports arguments -march=armv9-a+sve2+crypto: YES
Message: Using machine args: ['-march=armv9-a+sve2+crypto']
> I think this is what we want instead:
> Use march if supported,
> then use fallback_march if supported,
> then use the other fallback marchs.
>
> If the above is indeed what we want, we could just put this after
> endforeach (in the original version):
>
> # at this point, candidate march is either
> part_number_config['fallback_march'] or some other lower version
> if (part_number_config.has_key('fallback_march') and
> candidate_march != part_number_config['march'] and
> cc.has_argument('-march=' + part_number_config['fallback_march']))
> # this overwrites only the lower version with preferred
> fallback_march, if supported
> candidate_march = part_number_config['fallback_march']
> endif
>
> This way we won't even need the fallback_march variable.
Sure, I will change remove fallback_march variable, Thanks.
>
> > endif
> > endforeach
> > endif
> >
> > if candidate_march != part_number_config['march']
> > + if fallback_march != ''
> > + candidate_march = fallback_march
> > + endif
> > warning('Configuration march version is @0@, not supported.'
> > .format(part_number_config['march']))
> > if candidate_march != ''
> > --
> > 2.25.1
> >
On Mon, Feb 26, 2024 at 8:11 AM Pavan Nikhilesh Bhagavatula
<pbhagavatula@marvell.com> wrote:
>
> > On Thu, Feb 22, 2024 at 1:45 PM <pbhagavatula@marvell.com> wrote:
> > >
> > > From: Pavan Nikhilesh <pbhagavatula@marvell.com>
> > >
> > > Some ARM CPUs have specific march requirements and
> > > are not compatible with the supported march list.
> > > Add fallback march in case the mcpu and the march
> > > advertised in the part_number_config are not supported
> > > by the compiler.
> > >
> > > Example
> > > mcpu = neoverse-n2
> > > march = armv9-a
> > > fallback_march = armv8.5-a
> > >
> > > mcpu, march not supported
> > > machine_args = ['-march=armv8.5-a']
> > >
> > > mcpu, march, fallback_march not supported
> > > least march supported = armv8-a
> > >
> > > machine_args = ['-march=armv8-a']
> > >
Ah, of course, fallback march is only applied if when candidate_march
!= part_number_config['march']. Thanks.
> > > Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
> > > ---
> > > config/arm/meson.build | 14 +++++++++++---
> > > 1 file changed, 11 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/config/arm/meson.build b/config/arm/meson.build
> > > index d05d54b564..87ff5039f6 100644
> > > --- a/config/arm/meson.build
> > > +++ b/config/arm/meson.build
> > > @@ -94,6 +94,7 @@ part_number_config_arm = {
> > > '0xd49': {
> > > 'march': 'armv9-a',
> > > 'march_features': ['sve2'],
> > > + 'fallback_march': 'armv8.5-a',
> > > 'mcpu': 'neoverse-n2',
> > > 'flags': [
> > > ['RTE_MACHINE', '"neoverse-n2"'],
> > > @@ -708,6 +709,7 @@ if update_flags
> > >
> > > candidate_mcpu = ''
> > > candidate_march = ''
> > > + fallback_march = ''
> > >
> > > if part_number_config.has_key('mcpu') and
> > > cc.has_argument('-mcpu=' + part_number_config['mcpu'])
> > > @@ -736,16 +738,22 @@ if update_flags
> > > # start checking from this version downwards
> > > check_compiler_support = true
> > > endif
> > > - if (check_compiler_support and
> > > + if (check_compiler_support and candidate_march == '' and
> > > cc.has_argument('-march=' + supported_march))
> > > candidate_march = supported_march
> > > - # highest supported march version found
> > > - break
> > > + endif
> > > + if (part_number_config.has_key('fallback_march') and
> > > + supported_march == part_number_config['fallback_march'] and
> > > + cc.has_argument('-march=' + supported_march))
> > > + fallback_march = supported_march
> >
> > If both fallback_march and march are supported, fallback_march is
> > going to be chosen over march.
>
> The current flow still chooses the march
>
> Message: Arm implementer: Arm
> Message: Arm part number: 0xd49
> Compiler for C supports arguments -march=armv9-a: YES
> Compiler for C supports arguments -march=armv8.5-a: YES
> Compiler for C supports arguments -march=armv9-a+sve2: YES
> Compiler for C supports arguments -march=armv9-a+sve2+crypto: YES
> Message: Using machine args: ['-march=armv9-a+sve2+crypto']
>
>
> > I think this is what we want instead:
> > Use march if supported,
> > then use fallback_march if supported,
> > then use the other fallback marchs.
> >
> > If the above is indeed what we want, we could just put this after
> > endforeach (in the original version):
> >
> > # at this point, candidate march is either
> > part_number_config['fallback_march'] or some other lower version
> > if (part_number_config.has_key('fallback_march') and
> > candidate_march != part_number_config['march'] and
> > cc.has_argument('-march=' + part_number_config['fallback_march']))
> > # this overwrites only the lower version with preferred
> > fallback_march, if supported
> > candidate_march = part_number_config['fallback_march']
> > endif
> >
> > This way we won't even need the fallback_march variable.
>
> Sure, I will change remove fallback_march variable, Thanks.
>
> >
> > > endif
> > > endforeach
> > > endif
> > >
> > > if candidate_march != part_number_config['march']
> > > + if fallback_march != ''
> > > + candidate_march = fallback_march
> > > + endif
> > > warning('Configuration march version is @0@, not supported.'
> > > .format(part_number_config['march']))
> > > if candidate_march != ''
> > > --
> > > 2.25.1
> > >
I Forgot to add my tag:
Reviewed-by: Juraj Linkeš <juraj.linkes@pantheon.tech>
On Mon, Feb 26, 2024 at 8:31 AM Juraj Linkeš <juraj.linkes@pantheon.tech> wrote:
>
> On Mon, Feb 26, 2024 at 8:11 AM Pavan Nikhilesh Bhagavatula
> <pbhagavatula@marvell.com> wrote:
> >
> > > On Thu, Feb 22, 2024 at 1:45 PM <pbhagavatula@marvell.com> wrote:
> > > >
> > > > From: Pavan Nikhilesh <pbhagavatula@marvell.com>
> > > >
> > > > Some ARM CPUs have specific march requirements and
> > > > are not compatible with the supported march list.
> > > > Add fallback march in case the mcpu and the march
> > > > advertised in the part_number_config are not supported
> > > > by the compiler.
> > > >
> > > > Example
> > > > mcpu = neoverse-n2
> > > > march = armv9-a
> > > > fallback_march = armv8.5-a
> > > >
> > > > mcpu, march not supported
> > > > machine_args = ['-march=armv8.5-a']
> > > >
> > > > mcpu, march, fallback_march not supported
> > > > least march supported = armv8-a
> > > >
> > > > machine_args = ['-march=armv8-a']
> > > >
>
> Ah, of course, fallback march is only applied if when candidate_march
> != part_number_config['march']. Thanks.
>
> > > > Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
> > > > ---
> > > > config/arm/meson.build | 14 +++++++++++---
> > > > 1 file changed, 11 insertions(+), 3 deletions(-)
> > > >
> > > > diff --git a/config/arm/meson.build b/config/arm/meson.build
> > > > index d05d54b564..87ff5039f6 100644
> > > > --- a/config/arm/meson.build
> > > > +++ b/config/arm/meson.build
> > > > @@ -94,6 +94,7 @@ part_number_config_arm = {
> > > > '0xd49': {
> > > > 'march': 'armv9-a',
> > > > 'march_features': ['sve2'],
> > > > + 'fallback_march': 'armv8.5-a',
> > > > 'mcpu': 'neoverse-n2',
> > > > 'flags': [
> > > > ['RTE_MACHINE', '"neoverse-n2"'],
> > > > @@ -708,6 +709,7 @@ if update_flags
> > > >
> > > > candidate_mcpu = ''
> > > > candidate_march = ''
> > > > + fallback_march = ''
> > > >
> > > > if part_number_config.has_key('mcpu') and
> > > > cc.has_argument('-mcpu=' + part_number_config['mcpu'])
> > > > @@ -736,16 +738,22 @@ if update_flags
> > > > # start checking from this version downwards
> > > > check_compiler_support = true
> > > > endif
> > > > - if (check_compiler_support and
> > > > + if (check_compiler_support and candidate_march == '' and
> > > > cc.has_argument('-march=' + supported_march))
> > > > candidate_march = supported_march
> > > > - # highest supported march version found
> > > > - break
> > > > + endif
> > > > + if (part_number_config.has_key('fallback_march') and
> > > > + supported_march == part_number_config['fallback_march'] and
> > > > + cc.has_argument('-march=' + supported_march))
> > > > + fallback_march = supported_march
> > >
> > > If both fallback_march and march are supported, fallback_march is
> > > going to be chosen over march.
> >
> > The current flow still chooses the march
> >
> > Message: Arm implementer: Arm
> > Message: Arm part number: 0xd49
> > Compiler for C supports arguments -march=armv9-a: YES
> > Compiler for C supports arguments -march=armv8.5-a: YES
> > Compiler for C supports arguments -march=armv9-a+sve2: YES
> > Compiler for C supports arguments -march=armv9-a+sve2+crypto: YES
> > Message: Using machine args: ['-march=armv9-a+sve2+crypto']
> >
> >
> > > I think this is what we want instead:
> > > Use march if supported,
> > > then use fallback_march if supported,
> > > then use the other fallback marchs.
> > >
> > > If the above is indeed what we want, we could just put this after
> > > endforeach (in the original version):
> > >
> > > # at this point, candidate march is either
> > > part_number_config['fallback_march'] or some other lower version
> > > if (part_number_config.has_key('fallback_march') and
> > > candidate_march != part_number_config['march'] and
> > > cc.has_argument('-march=' + part_number_config['fallback_march']))
> > > # this overwrites only the lower version with preferred
> > > fallback_march, if supported
> > > candidate_march = part_number_config['fallback_march']
> > > endif
> > >
> > > This way we won't even need the fallback_march variable.
> >
> > Sure, I will change remove fallback_march variable, Thanks.
> >
> > >
> > > > endif
> > > > endforeach
> > > > endif
> > > >
> > > > if candidate_march != part_number_config['march']
> > > > + if fallback_march != ''
> > > > + candidate_march = fallback_march
> > > > + endif
> > > > warning('Configuration march version is @0@, not supported.'
> > > > .format(part_number_config['march']))
> > > > if candidate_march != ''
> > > > --
> > > > 2.25.1
> > > >
@@ -94,6 +94,7 @@ part_number_config_arm = {
'0xd49': {
'march': 'armv9-a',
'march_features': ['sve2'],
+ 'fallback_march': 'armv8.5-a',
'mcpu': 'neoverse-n2',
'flags': [
['RTE_MACHINE', '"neoverse-n2"'],
@@ -708,6 +709,7 @@ if update_flags
candidate_mcpu = ''
candidate_march = ''
+ fallback_march = ''
if part_number_config.has_key('mcpu') and
cc.has_argument('-mcpu=' + part_number_config['mcpu'])
@@ -736,16 +738,22 @@ if update_flags
# start checking from this version downwards
check_compiler_support = true
endif
- if (check_compiler_support and
+ if (check_compiler_support and candidate_march == '' and
cc.has_argument('-march=' + supported_march))
candidate_march = supported_march
- # highest supported march version found
- break
+ endif
+ if (part_number_config.has_key('fallback_march') and
+ supported_march == part_number_config['fallback_march'] and
+ cc.has_argument('-march=' + supported_march))
+ fallback_march = supported_march
endif
endforeach
endif
if candidate_march != part_number_config['march']
+ if fallback_march != ''
+ candidate_march = fallback_march
+ endif
warning('Configuration march version is @0@, not supported.'
.format(part_number_config['march']))
if candidate_march != ''