Re: [dpdk-stable] [PATCH 20.11] config/arm: replace native machine args

[Jerin Jacob Kollanukkaran <jerinj@marvell.com>]

> -----Original Message-----
> From: Ruifeng Wang <Ruifeng.Wang@arm.com>
> Sent: Saturday, February 20, 2021 9:13 AM
> To: Juraj Linkeš <juraj.linkes@pantheon.tech>; Luca Boccassi
> <bluca@debian.org>; stable@dpdk.org; Jerin Jacob Kollanukkaran
> <jerinj@marvell.com>
> Cc: david.marchand@redhat.com; nd <nd@arm.com>
> Subject: [EXT] RE: [PATCH 20.11] config/arm: replace native machine args
> 
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> 
> ----------------------------------------------------------------------
> > -----Original Message-----
> > From: Juraj Linkeš <juraj.linkes@pantheon.tech>
> > Sent: Friday, February 19, 2021 8:10 PM
> > To: Luca Boccassi <bluca@debian.org>; stable@dpdk.org
> > Cc: jerinj@marvell.com; Ruifeng Wang <Ruifeng.Wang@arm.com>;
> > david.marchand@redhat.com
> > Subject: RE: [PATCH 20.11] config/arm: replace native machine args
> >
> >
> >
> > > -----Original Message-----
> > > From: Luca Boccassi <bluca@debian.org>
> > > Sent: Friday, February 19, 2021 12:33 PM
> > > To: Juraj Linkeš <juraj.linkes@pantheon.tech>; stable@dpdk.org
> > > Cc: jerinj@marvell.com; ruifeng.wang@arm.com;
> > > david.marchand@redhat.com
> > > Subject: Re: [PATCH 20.11] config/arm: replace native machine args
> > >
> > > On Fri, 2021-02-19 at 11:06 +0000, Juraj Linkeš wrote:
> > > > > -----Original Message-----
> > > > > From: luca.boccassi@gmail.com <luca.boccassi@gmail.com>
> > > > > Sent: Friday, February 19, 2021 11:58 AM
> > > > > To: stable@dpdk.org
> > > > > Cc: Juraj Linkeš <juraj.linkes@pantheon.tech>;
> > > > > jerinj@marvell.com; ruifeng.wang@arm.com;
> > > > > david.marchand@redhat.com
> > > > > Subject: [PATCH 20.11] config/arm: replace native machine args
> > > > >
> > > > > From: Juraj Linkeš <juraj.linkes@pantheon.tech>
> > > > >
> > > > > [ backported from upstream commit
> > > > > 9186e5a07f35ae74a1f7fa2d89671b5f77eae407 ]
> > > > >
> > > > > There are compiler issues when building with -mcpu=native with
> > > > > popular compilers, such as GCC-8.4:
> > > > > In file included from ../lib/librte_eal/arm/include/rte_vect.h:11,
> > > > >                  from ../lib/librte_net/net_crc_neon.c:10:
> > > > > ../lib/librte_net/net_crc_neon.c: In function ‘crcr32_folding_round’:
> > > > > /usr/lib/gcc/aarch64-linux-gnu/8/include/arm_neon.h:26094:1: error:
> > > > > inlining failed in call to always_inline ‘vmull_p64’:
> > > > > target specific option mismatch
> > > > >  vmull_p64 (poly64_t a, poly64_t b)
> > > > > ../lib/librte_net/net_crc_neon.c:50:20: note: called from here
> > > > >   uint64x2_t tmp1 = vreinterpretq_u64_p128(vmull_p64(
> > > > >     vgetq_lane_p64(vreinterpretq_p64_u64(fold), 0),
> > > > >     vgetq_lane_p64(vreinterpretq_p64_u64(precomp), 1)));
> > > > >
> > > > > and clang:
> > > > > gcc -E -dM -mcpu="native" - < /dev/null | grep
> > > > > __ARM_FEATURE_ATOMICS
> > > > > clang-9 -E -dM -mcpu="native" - < /dev/null | grep
> > > > > __ARM_FEATURE_ATOMICS <no output> # no clang support
> > > > >
> > > > > Fix this by always specifying the proper machine args and never
> > > > > using the native flags.
> > > > >
> > > > > Fixes: 78ac8eac7e8a ("config/arm: use native machine build
> > > > > arguments")
> > > > >
> > > > > Signed-off-by: Juraj Linkeš <juraj.linkes@pantheon.tech>
> > > > > Signed-off-by: Luca Boccassi <luca.boccassi@microsoft.com>
> > > > > ---
> > > > > This is a crude backport, but it fixes the build for arm64. It's
> > > > > a release blocker for 20.11.1, so I would appreciate a quick review.
> > > > > Thanks!
> > > >
> > > > What does this fix? With or without the below change, the native
> > > > machine
> > > args are not used. The patch shoudn't actually change the
> > > configuration of the build at all, so I'm a bit confused.
> > >
> > > It fixes the build on some build workers with thunderx hardware -
> > > without this I get failures like:
> > >
> > > arm_neon.h:26647:1: error: inlining failed in call to 'always_inline'
> > > 'vmull_p64': target specific option mismatch
> > >
> >
> > I tried the patch and I'm seeing the same errors on a ThunderX server
> > (with and without the patch). Is this actually the right patch?
> >
> > One of the four failures looks like this:
> > In file included from ../lib/librte_eal/arm/include/rte_vect.h:11,
> >                  from ../lib/librte_net/net_crc_neon.c:10:
> > ../lib/librte_net/net_crc_neon.c: In function 'crcr32_folding_round':
> > /usr/lib/gcc/aarch64-linux-gnu/8/include/arm_neon.h:26094:1: error:
> > inlining failed in call to always_inline 'vmull_p64': target specific
> > option mismatch
> >  vmull_p64 (poly64_t a, poly64_t b)
> >  ^~~~~~~~~
> > ../lib/librte_net/net_crc_neon.c:50:20: note: called from here
> >   uint64x2_t tmp1 = vreinterpretq_u64_p128(vmull_p64(
> >                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >     vgetq_lane_p64(vreinterpretq_p64_u64(fold), 0),
> >     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >     vgetq_lane_p64(vreinterpretq_p64_u64(precomp), 1)));
> >     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >
> > Ruifeng, any ideas on how to fix this?
> 
> Gcc build on ThunderX platform is broken. Issue can be seen in some CentOS-8
> OBS builds.
> https://urldefense.proofpoint.com/v2/url?u=https-
> 3A__mails.dpdk.org_archives_dev_2020-
> 2DNovember_192909.html&d=DwIGaQ&c=nKjWec2b6R0mOyPaz7xtfQ&r=1DG
> ob4H4rxz6H8uITozGOCa0s5f4wCNtTa4UUKvcsvI&m=mgzJ6z43dsDFwI6rdgKCUj
> 0GCMNjEKQAa7dfRZxvrdU&s=UWUJTFdGC2mD2x-rcuRnH1I7-
> 1jKFC40Bh5hFanzu0A&e=
> I tried tuning compiler flags used, but could not resolve the issue.
> 
> Need help from Marvell to look at this.
> Hi Jerin, do you have any thoughts on this?


Ruifeng, If you are able to reproduce this issue, Could you add "-march=armv8.1-a+crc+crypto" In ThunderX config  and check is this
Fixing the issue?

[main] [dpdk.org] $ git diff
diff --git a/config/arm/meson.build b/config/arm/meson.build
index 00bc4610a..ef65b4bb6 100644
--- a/config/arm/meson.build
+++ b/config/arm/meson.build
@@ -96,15 +96,18 @@ implementer_cavium = {
        ],
        'part_number_config': {
                '0xa1': {
-                       'machine_args': ['-mcpu=thunderxt88'],
+                       'machine_args': ['-march=armv8.1-a+crc+crypto+lse',
+                                        '-mcpu=thunderxt88'],
                        'flags': flags_part_number_thunderx
                },
                '0xa2': {
-                       'machine_args': ['-mcpu=thunderxt81'],
+                       'machine_args': ['-march=armv8.1-a+crc+crypto+lse',
+                                        '-mcpu=thunderxt81'],
                        'flags': flags_part_number_thunderx
                },
                '0xa3': {
-                       'machine_args': ['-mcpu=thunderxt83'],
+                       'machine_args': ['-march=armv8.1-a+crc+crypto+lse',
+                                        '-mcpu=thunderxt83'],
                        'flags': flags_part_number_thunderx
                },
                '0xaf': {

> >
> > > --
> > > Kind regards,
> > > Luca Boccassi