From: "Juraj Linkeš" <juraj.linkes@pantheon.tech>
To: Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com>
Cc: Jerin Jacob <jerinj@marvell.com>,
"Ruifeng.Wang@arm.com" <Ruifeng.Wang@arm.com>,
"nd@arm.com" <nd@arm.com>,
Bruce Richardson <bruce.richardson@intel.com>,
"dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [EXT] Re: [PATCH 2/2] config/arm: add support for fallback march
Date: Mon, 22 Jan 2024 17:29:13 +0100 [thread overview]
Message-ID: <CAOb5WZbDx1-0wDt9SKqjVvi-xZszvif=M_YO-9XkMJCbwmhZKw@mail.gmail.com> (raw)
In-Reply-To: <PH0PR18MB40867C8D56C01EEBD7F71F49DE752@PH0PR18MB4086.namprd18.prod.outlook.com>
On Mon, Jan 22, 2024 at 1:16 PM Pavan Nikhilesh Bhagavatula
<pbhagavatula@marvell.com> wrote:
>
> > On Sun, Jan 21, 2024 at 10:37 AM <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.
> > >
> >
> > It's not clear to me what this patch adds. We already have a fallback
> > mechanism and this basically does the same thing, but there's some
> > extra logic that's not clear to me. Looks like there are some extra
> > conditions around mcpu. In that case, all of the mcpu/march processing
> > should be done first and then we should do a common fallback.
> >
>
> The current fallback does a simple reverse compatibility check with the compiler
> when force march is not enabled.
> But this is not true for neoverse-n2 case, as it is based on armv9-a which is a super set of
> armv8.5-a and other features[1]
> In the current fallback path if both march neoverse-n2 and mcpu armv9-a are not supported
> then it would fallback to armv8.6-a but this not correct as neoverse-n2 is not based on armv8.5-a
>
> The fallback march armv8.5-a kicks in (if supported) when neoverse-n2 and armv9-a are not supported.
>
Can the two fallback mechanisms be combined? They seem very similar.
>
> [1] https://github.com/gcc-mirror/gcc/blob/615e25c82de97acc17ab438f88d6788cf7ffe1d6/gcc/config/arm/arm-cpus.in#L306
>
>
> > > 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 | 15 +++++++++++++--
> > > 1 file changed, 13 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/config/arm/meson.build b/config/arm/meson.build
> > > index 8c8cfccca0..2aaf78a81a 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"'],
> > > @@ -709,14 +710,14 @@ if update_flags
> > >
> > > # probe supported archs and their features
> > > candidate_march = ''
> > > + supported_marchs = ['armv9-a', 'armv8.6-a', 'armv8.5-a', 'armv8.4-a',
> > > + 'armv8.3-a', 'armv8.2-a', 'armv8.1-a', 'armv8-a']
> > > if part_number_config.has_key('march')
> > > if part_number_config.get('force_march', false) or support_mcpu
> > > if cc.has_argument('-march=' + part_number_config['march'])
> > > candidate_march = part_number_config['march']
> > > endif
> > > else
> > > - supported_marchs = ['armv8.6-a', 'armv8.5-a', 'armv8.4-a', 'armv8.3-
> > a',
> > > - 'armv8.2-a', 'armv8.1-a', 'armv8-a']
> > > check_compiler_support = false
> > > foreach supported_march: supported_marchs
> > > if supported_march == part_number_config['march']
> > > @@ -733,6 +734,16 @@ if update_flags
> > > endif
> > >
> > > if candidate_march != part_number_config['march']
> > > + if part_number_config.has_key('fallback_march') and not
> > support_mcpu
> > > + fallback_march = part_number_config['fallback_march']
> > > + foreach supported_march: supported_marchs
> > > + if (supported_march == fallback_march
> > > + and cc.has_argument('-march=' + supported_march))
> > > + candidate_march = supported_march
> > > + break
> > > + endif
> > > + endforeach
> > > + endif
> > > warning('Configuration march version is @0@, not supported.'
> > > .format(part_number_config['march']))
> > > if candidate_march != ''
> > > --
> > > 2.25.1
> > >
next prev parent reply other threads:[~2024-01-22 16:29 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 [this message]
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
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAOb5WZbDx1-0wDt9SKqjVvi-xZszvif=M_YO-9XkMJCbwmhZKw@mail.gmail.com' \
--to=juraj.linkes@pantheon.tech \
--cc=Ruifeng.Wang@arm.com \
--cc=bruce.richardson@intel.com \
--cc=dev@dpdk.org \
--cc=jerinj@marvell.com \
--cc=nd@arm.com \
--cc=pbhagavatula@marvell.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).