Re: [dpdk-dev] [PATCH 3/4] devtools: add ppc64 in meson build test

[Thomas Monjalon <thomas@monjalon.net>]

15/06/2020 23:43, David Christensen:
> On 6/14/20 3:57 PM, Thomas Monjalon wrote:
> > diff --git a/devtools/test-meson-builds.sh b/devtools/test-meson-builds.sh
> > index 1d80a029aa..1cde17a2e5 100755
> > --- a/devtools/test-meson-builds.sh
> > +++ b/devtools/test-meson-builds.sh
> > @@ -212,6 +212,11 @@ for f in $srcdir/config/arm/arm64_[bdo]*gcc ; do
> >   	unset CC
> >   done
> > 
> > +# ppc configurations
> > +for f in $srcdir/config/ppc/ppc* ; do
> > +	build build-$(basename $f | cut -d'-' -f-2) $f $use_shared
> > +done
> > +
> 
> The entire script file is poorly structured for multi-architecture 
> builds.  The script fails on PPC64LE even before your changes:

This script supports only builds from x86 Linux so far.
This patch is adding cross-compilation of ppc from x86,
and it works fine.


> ------------------------------------
> # shared and static linked builds with gcc and clang
> for c in gcc clang ; do
>         command -v $c >/dev/null 2>&1 || continue
>         for s in static shared ; do
>                 export CC="$CCACHE $c"
>                 build build-$c-$s $c --default-library=$s
>                 unset CC
>         done
> done
> ------------------------------------
> 
> Compilation on clang is not currently supported due to build failures on 
> Altivec data types for vectorization:
> 
> In file included from ../lib/librte_eal/common/eal_common_options.c:33:
> In file included from ../lib/librte_eal/ppc/include/rte_memcpy.h:12:
> In file included from ../lib/librte_eal/ppc/include/rte_altivec.h:10:
> /usr/lib64/clang/9.0.1/include/altivec.h:55:19: error: unknown type name 
> 'vector'
> static __inline__ vector bool char __ATTRS_o_ai
>                    ^
> /usr/lib64/clang/9.0.1/include/altivec.h:56:10: error: unknown type name 
> 'vector'
> vec_perm(vector bool char __a, vector bool char __b, vector unsigned 
> char __c);
> 
> and C99 atomics:
> 
> ../lib/librte_eal/ppc/include/rte_atomic.h:85:9: error: implicit 
> declaration of function '__atomic_exchange_2' is invalid in C99 
> [-Werror,-Wimplicit-function-declaration]
>          return __atomic_exchange_2(dst, val, __ATOMIC_SEQ_CST);
>                 ^
> 
> The script then immediately launches into an x86 build no matter what 
> architecture the system is running on:
> 
> ------------------------------------
> default_machine='nehalem'
> ok=$(cc -march=$default_machine -E - < /dev/null > /dev/null 2>&1 || 
> echo false)
> if [ "$ok" = "false" ] ; then
>          default_machine='corei7'
> fi
> build build-x86-default cc -Dlibdir=lib -Dmachine=$default_machine 
> $use_shared
> ------------------------------------
> 
> Which also fails on a Power system:
> 
> ninja -v -C ./build-x86-default
> ninja: Entering directory `./build-x86-default'
> [1/2265] cc -Ilib/76b5a35@@rte_kvargs@sta -Ilib -I../lib -I. -I../ 
> -Iconfig -I../config -Ilib/librte_eal/include 
> -I../lib/librte_eal/include -Ilib/librte_eal/linux/include 
> -I../lib/librte_eal/linux/include -Ilib/librte_eal/ppc/include 
> -I../lib/librte_eal/ppc/include -Ilib/librte_kvargs 
> -I../lib/librte_kvargs -fdiagnostics-color=always -pipe 
> -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Werror -O2 -g -include 
> rte_config.h -Wextra -Wcast-qual -Wdeprecated -Wformat-nonliteral 
> -Wformat-security -Wmissing-declarations -Wmissing-prototypes 
> -Wnested-externs -Wold-style-definition -Wpointer-arith -Wsign-compare 
> -Wstrict-prototypes -Wundef -Wwrite-strings -Wno-packed-not-aligned 
> -Wno-missing-field-initializers -D_GNU_SOURCE -fPIC -mcpu=corei7 
> -mtune=corei7 -DALLOW_EXPERIMENTAL_API -DALLOW_INTERNAL_API 
> -Wno-format-truncation  -MD -MQ 
> 'lib/76b5a35@@rte_kvargs@sta/librte_kvargs_rte_kvargs.c.o' -MF 
> 'lib/76b5a35@@rte_kvargs@sta/librte_kvargs_rte_kvargs.c.o.d' -o 
> 'lib/76b5a35@@rte_kvargs@sta/librte_kvargs_rte_kvargs.c.o' -c 
> ../lib/librte_kvargs/rte_kvargs.c
> FAILED: lib/76b5a35@@rte_kvargs@sta/librte_kvargs_rte_kvargs.c.o
> 
> 
> I think the logic of looping through supported configs for test builds 
> is the right one, but more changes are required for multi-architecture 
> support in this script.  For now I'd abandon the PPC/ARM support 
> entirely in this script.

I am adding PPC compilation check to avoid having PPC broken,
because after asking for many years to IBM execs,
there is still no PPC CI integrated in DPDK patchwork.
If you don't think this small step is going in the right direction,
then I will stop bothering about PPC support,
and we should probably completely drop PPC support I guess.