AVX512 was disabled for GCC because of Bugzilla issue 97 [1], the GCC defect submitted for the issue [2] highlighted that this is a known binutils version 2.30 issue.
Narrowed the scope of no-avx512 to the this specific binutils version. [1] https://bugs.dpdk.org/show_bug.cgi?id=97 [2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88096 Fixes: 8d07c82b239f ("mk: disable gcc AVX512F support") Cc: sta...@dpdk.org Signed-off-by: Ferruh Yigit <ferruh.yi...@intel.com> --- Cc: Tom Barbette <barbe...@kth.se> Cc: Thomas Monjalon <tho...@monjalon.net> Cc: Yongseok Koh <ys...@mellanox.com> Cc: Konstantin Ananyev <konstantin.anan...@intel.com> Cc: Bruce Richardson <bruce.richard...@intel.com> v2: * Added warning message (print only once for eal) * Moved decision details to compat file, kept execution in cpuflags v3: * replace 'ld' with '$(LD)' for cross build * added meson support --- config/meson.build | 8 ++++++++ mk/rte.cpuflags.mk | 4 ++-- mk/toolchain/gcc/rte.toolchain-compat.mk | 10 ++++++++++ 3 files changed, 20 insertions(+), 2 deletions(-) diff --git a/config/meson.build b/config/meson.build index db32499b3..40802fc88 100644 --- a/config/meson.build +++ b/config/meson.build @@ -43,6 +43,14 @@ toolchain = cc.get_id() dpdk_conf.set_quoted('RTE_TOOLCHAIN', toolchain) dpdk_conf.set('RTE_TOOLCHAIN_' + toolchain.to_upper(), 1) +# get binutils version for the workaround of Bug 97 +ldver = run_command('ld', '-v').stdout().strip() +if ldver.contains('2.30') + if cc.has_argument('-mno-avx512f') + machine_args += '-mno-avx512f' + endif +endif + add_project_link_arguments('-Wl,--no-as-needed', language: 'c') dpdk_extra_ldflags += '-Wl,--no-as-needed' diff --git a/mk/rte.cpuflags.mk b/mk/rte.cpuflags.mk index c3291b17a..541211c61 100644 --- a/mk/rte.cpuflags.mk +++ b/mk/rte.cpuflags.mk @@ -69,8 +69,8 @@ ifneq ($(filter $(AUTO_CPUFLAGS),__AVX512F__),) ifeq ($(CONFIG_RTE_ENABLE_AVX512),y) CPUFLAGS += AVX512F else -# disable AVX512F support of gcc as a workaround for Bug 97 -ifeq ($(CONFIG_RTE_TOOLCHAIN_GCC),y) +# disable AVX512F support for GCC & binutils 2.30 as a workaround for Bug 97 +ifeq ($(FORCE_DISABLE_AVX512),y) MACHINE_CFLAGS += -mno-avx512f endif endif diff --git a/mk/toolchain/gcc/rte.toolchain-compat.mk b/mk/toolchain/gcc/rte.toolchain-compat.mk index 44904295c..33ea3f03a 100644 --- a/mk/toolchain/gcc/rte.toolchain-compat.mk +++ b/mk/toolchain/gcc/rte.toolchain-compat.mk @@ -20,6 +20,16 @@ HOST_GCC_MINOR = $(shell echo __GNUC_MINOR__ | $(HOSTCC) -E -x c - | tail -n 1) HOST_GCC_PATCHLEVEL = $(shell echo __GNUC_PATCHLEVEL__ | $(HOSTCC) -E -x c - | tail -n 1) HOST_GCC_VERSION = $(HOST_GCC_MAJOR)$(HOST_GCC_MINOR) +LD_VERSION = $(shell $(LD) -v) +# disable AVX512F support for GCC & binutils 2.30 as a workaround for Bug 97 +ifneq ($(filter 2.30%,$(LD_VERSION)),) +FORCE_DISABLE_AVX512 := y +# print warning only once for librte_eal +ifneq ($(filter %librte_eal,$(lastword $(CURDIR))),) +$(warning AVX512 support disabled because of ld 2.30. See Bug 97) +endif +endif + # if GCC is older than 4.x ifeq ($(shell test $(GCC_VERSION) -lt 40 && echo 1), 1) MACHINE_CFLAGS = -- 2.17.2
