[meta-intel] [meta-dpdk][PATCH] dpdk: workaround sse mismatch error

[Hongxu Jia]

On 2018年10月11日 08:21, Anuj Mittal wrote:
> Hi Hongxu
>
> On 10/10/2018 11:18 PM, Hongxu Jia wrote:
>> Since commit `7f6bffb dpdk: support build with external & multilib toolchains' applied,
>> it added var-HOST_CC_ARCH in which has option `-march=**' to enable specific SSE for
>> specific arch that causing SSE mismatch error while compiling
>> [snip]
>> | recipe-sysroot-native/usr/lib/i586-wrs-linux/gcc/i586-wrs-linux/8.2.0/include/
>> xmmintrin.h:1232:1: error: inlining failed in call to always_inline '_mm_sfence':
>> target specific option mismatch
>> |  _mm_sfence (void)
>> |  ^~~~~~~~~~
>> | In file included from git/lib/librte_eal/linuxapp/eal/eal_thread.c:16:
>> | git/i686-native-linuxapp-gcc/include/rte_atomic.h:26:19: note: called from here
>> |  #define rte_wmb() _mm_sfence()
>> |                    ^~~~~~~~~~~~
>> | git/lib/librte_eal/linuxapp/eal/eal_thread.c:155:3: note: in expansion of macro 'rte_wmb'
>> |    rte_wmb();
>> [snip]
>>
>> Choose `-march=native', which will select what is available on the processor. Although
>> it disable previously `-march=**' in var-HOST_CC_ARCH, but others options in var-HOST_CC_ARCH
>> (such as security flags `-fstack-protector-strong -D_FORTIFY_SOURCE=2') still works.
>>
> Is it possible that the value of -march is also being defined from
> somewhere within dpdk leading to a mismatch?

Hi Anuj,

I think so, since var-DPDK_TARGET_MACHINE is `default' which mismatch
with `-march=**' in var-HOST_CC_ARCH

For qemux86-64, while var-DPDK_TARGET_MACHINE is `default', its 
`-march=corei7',
it mismatch with `-march=core2' in var-HOST_CC_ARCH

[grep corei -rn mk]
mk/machine/native/rte.vars.mk:35:# so, set the compilation target to be 
a corei7, minimum target with SSE4.2.
mk/machine/native/rte.vars.mk:38:    MACHINE_CFLAGS = -march=corei7
mk/machine/default/rte.vars.mk:30:MACHINE_CFLAGS += -march=corei7
mk/machine/wsm/rte.vars.mk:30:MACHINE_CFLAGS = -march=corei7 -maes -mpclmul
mk/machine/snb/rte.vars.mk:30:MACHINE_CFLAGS = -march=corei7-avx
mk/machine/nhm/rte.vars.mk:30:MACHINE_CFLAGS = -march=corei
[grep corei -rn mk]

For default, its MACHINE_CFLAGS is ` -march=corei7', and set 
`DPDK_TARGET_MACHINE = 'corei5''
does not work, no mk/machine/corei5/rte.vars.mk to support it

I think this fix is not appropriate, please drop it. My suggestion is remove
var-HOST_CC_ARCH from do_compile, V2 incoming

//Hongxu



>> Refers:
>> https://stackoverflow.com/questions/10686638/whats-the-differrence-among-cflgs-sse-options-of-msse-msse2-mssse3-msse4
>> https://stackoverflow.com/questions/35772562/inlining-failed-in-call-to-always-inline-m128i-mm-cvtepu8-epi32-m128i-t
>> https://bugzilla.redhat.com/show_bug.cgi?id=1092991
>> https://bugzilla.gnome.org/show_bug.cgi?id=670690
>> https://stackoverflow.com/questions/51003218/gcc-target-for-avx2-disabling-sse-instruction-set
>>
>> Signed-off-by: Hongxu Jia <hongxu.jia at windriver.com>
>> ---
>>   recipes-extended/dpdk/dpdk.inc | 6 +++---
>>   1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/recipes-extended/dpdk/dpdk.inc b/recipes-extended/dpdk/dpdk.inc
>> index 194986b..b893e16 100644
>> --- a/recipes-extended/dpdk/dpdk.inc
>> +++ b/recipes-extended/dpdk/dpdk.inc
>> @@ -102,18 +102,18 @@ 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} -march=native ${TOOLCHAIN_OPTIONS} -I${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} -march=native ${TOOLCHAIN_OPTIONS} -I${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} -march=native  ${TOOLCHAIN_OPTIONS} -I${STAGING_INCDIR}" \
>>   		   CROSS="${TARGET_PREFIX}" O="${S}/test/$@/"
>>   }
>>   
>>