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From: "Juraj Linkeš" <juraj.linkes@pantheon.tech>
To: Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com>
Cc: Jerin Jacob <jerinj@marvell.com>, "nd@arm.com" <nd@arm.com>,
	 "wathsala.vithanage@arm.com" <wathsala.vithanage@arm.com>,
	Ruifeng Wang <ruifeng.wang@arm.com>,
	 Bruce Richardson <bruce.richardson@intel.com>,
	"dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [EXT] Re: [PATCH v5 2/3] config/arm: add support for fallback march
Date: Mon, 26 Feb 2024 08:31:09 +0100	[thread overview]
Message-ID: <CAOb5WZYH_BozvbqA8xm_dKTK2WucvK8qgtJhsc45F98yevBc1g@mail.gmail.com> (raw)
In-Reply-To: <PH0PR18MB4086262F0006B44772C6623ADE5A2@PH0PR18MB4086.namprd18.prod.outlook.com>

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
> > >

  reply	other threads:[~2024-02-26  7:31 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-21  9:36 [PATCH 1/2] config/arm: avoid mcpu and march conflicts pbhagavatula
2024-01-21  9:36 ` [PATCH 2/2] config/arm: add support for fallback march pbhagavatula
2024-01-22  6:30   ` Ruifeng Wang
2024-01-22 11:04   ` Juraj Linkeš
2024-01-22 12:16     ` [EXT] " Pavan Nikhilesh Bhagavatula
2024-01-22 16:29       ` Juraj Linkeš
2024-01-24 15:25         ` Pavan Nikhilesh Bhagavatula
2024-01-22  6:29 ` [PATCH 1/2] config/arm: avoid mcpu and march conflicts Ruifeng Wang
2024-01-22 10:55 ` Juraj Linkeš
2024-01-22 11:54   ` [EXT] " Pavan Nikhilesh Bhagavatula
2024-01-22 16:26     ` Juraj Linkeš
2024-01-24 15:21       ` Pavan Nikhilesh Bhagavatula
2024-01-29  8:44         ` Juraj Linkeš
2024-01-30 16:16           ` Pavan Nikhilesh Bhagavatula
2024-01-31  9:03             ` Juraj Linkeš
2024-02-01 21:57 ` [PATCH v2 1/3] " pbhagavatula
2024-02-01 21:57   ` [PATCH v2 2/3] config/arm: add support for fallback march pbhagavatula
2024-02-01 21:57   ` [PATCH v2 3/3] config/arm: allow WFE to be enabled config time pbhagavatula
2024-02-07  2:55     ` Honnappa Nagarahalli
2024-02-10  6:47       ` Pavan Nikhilesh Bhagavatula
2024-02-10 16:36         ` Honnappa Nagarahalli
2024-02-10 16:40           ` Pavan Nikhilesh Bhagavatula
2024-02-02  8:50   ` [PATCH v3 1/3] config/arm: avoid mcpu and march conflicts pbhagavatula
2024-02-02  8:50     ` [PATCH v3 2/3] config/arm: add support for fallback march pbhagavatula
2024-02-07 20:24       ` Wathsala Wathawana Vithanage
2024-02-02  8:50     ` [PATCH v3 3/3] config/arm: allow WFE to be enabled config time pbhagavatula
2024-02-10 16:56       ` Honnappa Nagarahalli
2024-02-12 19:21       ` Wathsala Wathawana Vithanage
2024-02-06  4:10     ` [PATCH v3 1/3] config/arm: avoid mcpu and march conflicts Wathsala Wathawana Vithanage
2024-02-06  4:44       ` Honnappa Nagarahalli
2024-02-06 10:21         ` Pavan Nikhilesh Bhagavatula
2024-02-07  0:01           ` Wathsala Wathawana Vithanage
2024-02-10  6:49             ` Pavan Nikhilesh Bhagavatula
2024-02-10 15:20               ` Honnappa Nagarahalli
2024-02-10 17:21                 ` Honnappa Nagarahalli
2024-02-21 20:20     ` [PATCH v4 " pbhagavatula
2024-02-21 20:20       ` [PATCH v4 2/3] config/arm: add support for fallback march pbhagavatula
2024-02-22 10:47         ` Juraj Linkeš
2024-02-22 12:32           ` [EXT] " Pavan Nikhilesh Bhagavatula
2024-02-21 20:20       ` [PATCH v4 3/3] config/arm: allow WFE to be enabled config time pbhagavatula
2024-02-22  9:37       ` [PATCH v4 1/3] config/arm: avoid mcpu and march conflicts Juraj Linkeš
2024-02-22  9:49         ` [EXT] " Pavan Nikhilesh Bhagavatula
2024-02-22 12:45       ` [PATCH v5 " pbhagavatula
2024-02-22 12:45         ` [PATCH v5 2/3] config/arm: add support for fallback march pbhagavatula
2024-02-23 11:49           ` Juraj Linkeš
2024-02-26  7:11             ` [EXT] " Pavan Nikhilesh Bhagavatula
2024-02-26  7:31               ` Juraj Linkeš [this message]
2024-02-26  7:34                 ` Juraj Linkeš
2024-02-22 12:45         ` [PATCH v5 3/3] config/arm: allow WFE to be enabled config time pbhagavatula
2024-02-23 11:19         ` [PATCH v5 1/3] config/arm: avoid mcpu and march conflicts Juraj Linkeš
2024-02-26  7:08           ` [EXT] " Pavan Nikhilesh Bhagavatula
2024-02-26  7:38         ` [PATCH v6 " pbhagavatula
2024-02-26  7:38           ` [PATCH v6 2/3] config/arm: add support for fallback march pbhagavatula
2024-02-26  7:38           ` [PATCH v6 3/3] config/arm: allow WFE to be enabled config time pbhagavatula
2024-03-06 15:49           ` [PATCH v7 1/3] config/arm: avoid mcpu and march conflicts pbhagavatula
2024-03-06 15:49             ` [PATCH v7 2/3] config/arm: add support for fallback march pbhagavatula
2024-03-06 15:49             ` [PATCH v7 3/3] config/arm: allow WFE to be enabled config time pbhagavatula
2024-03-07  3:57             ` [PATCH v7 1/3] config/arm: avoid mcpu and march conflicts Pavan Nikhilesh Bhagavatula
2024-03-14 11:38             ` [PATCH v8 1/5] " pbhagavatula
2024-03-14 11:38               ` [PATCH v8 2/5] config/arm: add armv9-a march support pbhagavatula
2024-03-14 11:38               ` [PATCH v8 3/5] config/arm: add crypto march feature to thunderxt83 pbhagavatula
2024-03-14 12:00                 ` Jerin Jacob
2024-03-14 11:38               ` [PATCH v8 4/5] config/arm: add support for fallback march pbhagavatula
2024-03-14 11:38               ` [PATCH v8 5/5] config/arm: allow WFE to be enabled config time pbhagavatula
2024-03-15 11:17               ` [PATCH v8 1/5] config/arm: avoid mcpu and march conflicts Thomas Monjalon

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