[yocto] [meta-dpdk][PATCH] dpdk: Fix do_compile failure for qemux86 and qemux86-64

[Mittal, Anuj]

On Tue, 2019-06-11 at 11:06 +0800, zhe.he at windriver.com wrote:
> From: He Zhe <zhe.he at windriver.com>
> 
> DPDK_TARGET_MACHINE in bbappend in other layers forms the dpdk-
> internal variable
> MACHINE_CFLAGS which is passed to dpdk compilation command line
> containing the
> first -march parameter. And EXTRA_CFLAGS in dpdk.inc is passed to
> dpdk command
> line containing the second -march parameter. By mistake, the first
> -march had
> always overwritten the second one until the following commit of GCC
> v9.1.0
> 8c0f695d83d1 ("driver: Also prune joined switches with negation").
> 
> Since it was fixed, the second -march, which was core2 for qemux86-64 
> or
> core2-32 for qemux86, began to take effect. But core2* does not have
> SSE4.2
> feature which is required by some dpdk instruction optimization and
> thus cause
> the following compilation failure.
> 
> 9.1.0/include/smmintrin.h:179:1: error: inlining failed in call to
> always_inline
> '_mm_blendv_epi8': target specific option mismatch
>   179 | _mm_blendv_epi8 (__m128i __X, __m128i __Y, __m128i __M)
>       | ^~~~~~~~~~~~~~~
> 
> This patch adds DPDK_EXTRA_CFLAGS to append appropriate -march,
> corei7 which is
> minimum and clear and independent of host machine, to dpdk
> compilation command
> line to overwrite all previous ones, without having to change dpdk
> source code.
> 
> Note that as we do not want to change the default tune core2* for
> qemux86*, this
> patch just fixes the compilation error. It would probably not be able
> to run on
> qemux86* with corei7 tune.

I don't think overriding arch values in recipe is appropriate. Also the
recipe is setting COMPATIBLE_MACHINE to be null because of this reason.
If the MACHINE that we're building for doesn't support the features
required, then we shouldn't be building dpdk for it in my opinion.

Thanks,

Anuj

> 
> Signed-off-by: He Zhe <zhe.he at windriver.com>
> ---
>  recipes-extended/dpdk/dpdk.inc | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/recipes-extended/dpdk/dpdk.inc b/recipes-
> extended/dpdk/dpdk.inc
> index a0e081a..0275e0c 100644
> --- a/recipes-extended/dpdk/dpdk.inc
> +++ b/recipes-extended/dpdk/dpdk.inc
> @@ -61,6 +61,9 @@ DPDK_RTE_TARGET_x86-64 = "x86_64-native-linuxapp-
> gcc"
>  DPDK_RTE_TARGET_x86 = "i686-native-linuxapp-gcc"
>  DPDK_RTE_TARGET_aarch64 = "arm64-${DPDK_TARGET_MACH}-linuxapp-gcc"
>  export RTE_TARGET = "${DPDK_RTE_TARGET}"
> +DPDK_EXTRA_CFLAGS = ""
> +DPDK_EXTRA_CFLAGS_qemux86 ?= "-march=corei7"
> +DPDK_EXTRA_CFLAGS_qemux86-64 ?= "-march=corei7"
>  
>  # The list of intel Comms platforms and their target machine
>  # process mapping. The supported target machine is listed under
> @@ -100,18 +103,18 @@ do_compile () {
>  
>  	cd ${S}/${RTE_TARGET}
>  	oe_runmake EXTRA_LDFLAGS="-L${STAGING_LIBDIR} --hash-style=gnu" 
> \
> -		   EXTRA_CFLAGS="${HOST_CC_ARCH} ${TOOLCHAIN_OPTIONS}
> -I${STAGING_INCDIR}" \
> +		   EXTRA_CFLAGS="${HOST_CC_ARCH} ${TOOLCHAIN_OPTIONS}
> ${DPDK_EXTRA_CFLAGS} -I${STAGING_INCDIR}" \
>  		   CROSS="${TARGET_PREFIX}" \
>  		   prefix=""  LDFLAGS="${TUNE_LDARGS}"  WERROR_FLAGS="-
> w" V=1
>  
>  	cd ${S}/examples/
>  	oe_runmake EXTRA_LDFLAGS="-L${STAGING_LIBDIR} --hash-style=gnu
> -fuse-ld=bfd" \
> -		   EXTRA_CFLAGS="${HOST_CC_ARCH} ${TOOLCHAIN_OPTIONS}
> -I${STAGING_INCDIR}" \
> +		   EXTRA_CFLAGS="${HOST_CC_ARCH} ${TOOLCHAIN_OPTIONS}
> ${DPDK_EXTRA_CFLAGS} -I${STAGING_INCDIR}" \
>  		   CROSS="${TARGET_PREFIX}" O="${S}/examples/$@/"
>  
>  	cd ${S}/test/
>  	oe_runmake EXTRA_LDFLAGS="-L${STAGING_LIBDIR} --hash-style=gnu
> -fuse-ld=bfd" \
> -		   EXTRA_CFLAGS="${HOST_CC_ARCH} ${TOOLCHAIN_OPTIONS}
> -I${STAGING_INCDIR}" \
> +		   EXTRA_CFLAGS="${HOST_CC_ARCH} ${TOOLCHAIN_OPTIONS}
> ${DPDK_EXTRA_CFLAGS} -I${STAGING_INCDIR}" \
>  		   CROSS="${TARGET_PREFIX}" O="${S}/test/$@/"
>  }
>