From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mellanox.co.il (mail-il-dmz.mellanox.com [193.47.165.129]) by dpdk.org (Postfix) with ESMTP id 19F9EA3 for ; Fri, 8 Mar 2019 18:48:48 +0100 (CET) Received: from Internal Mail-Server by MTLPINE1 (envelope-from yskoh@mellanox.com) with ESMTPS (AES256-SHA encrypted); 8 Mar 2019 19:48:46 +0200 Received: from scfae-sc-2.mti.labs.mlnx (scfae-sc-2.mti.labs.mlnx [10.101.0.96]) by labmailer.mlnx (8.13.8/8.13.8) with ESMTP id x28HloAm002625; Fri, 8 Mar 2019 19:48:44 +0200 From: Yongseok Koh To: Ferruh Yigit Cc: Thomas Monjalon , dpdk stable Date: Fri, 8 Mar 2019 09:47:10 -0800 Message-Id: <20190308174749.30771-32-yskoh@mellanox.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20190308174749.30771-1-yskoh@mellanox.com> References: <20190308174749.30771-1-yskoh@mellanox.com> Subject: [dpdk-stable] patch 'mk: fix scope of disabling AVX512F support' has been queued to LTS release 17.11.6 X-BeenThere: stable@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches for DPDK stable branches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 08 Mar 2019 17:48:48 -0000 Hi, FYI, your patch has been queued to LTS release 17.11.6 Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet. It will be pushed if I get no objection by 03/13/19. So please shout if anyone has objection. Also note that after the patch there's a diff of the upstream commit vs the patch applied to the branch. If the code is different (ie: not only metadata diffs), due for example to a change in context or macro names, please double check it. Thanks. Yongseok --- >>From e2e5744253733ce137e780699da00a627a25fc6a Mon Sep 17 00:00:00 2001 From: Ferruh Yigit Date: Mon, 14 Jan 2019 15:49:35 +0000 Subject: [PATCH] mk: fix scope of disabling AVX512F support [ backported from upstream commit a32ca9a4ebc1350ce48df0222decef95a72b742b ] 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: 1bc8541000ff ("mk: disable gcc AVX512F support") Signed-off-by: Ferruh Yigit Acked-by: Thomas Monjalon --- doc/guides/rel_notes/known_issues.rst | 35 ++++++++++++++++++++++++++++++++ mk/rte.cpuflags.mk | 4 ++-- mk/toolchain/gcc/rte.toolchain-compat.mk | 10 +++++++++ 3 files changed, 47 insertions(+), 2 deletions(-) diff --git a/doc/guides/rel_notes/known_issues.rst b/doc/guides/rel_notes/known_issues.rst index 3f6d8cb5f..fa0082137 100644 --- a/doc/guides/rel_notes/known_issues.rst +++ b/doc/guides/rel_notes/known_issues.rst @@ -742,3 +742,38 @@ igb_uio can not be used when running l3fwd-power **Driver/Module**: ``igb_uio`` module. + + +AVX-512 support disabled +------------------------ + +**Description**: + ``AVX-512`` support has been disabled on some conditions. + This shouldn't be confused with ``CONFIG_RTE_ENABLE_AVX512`` config option which is already + disabled by default. This config option defines if ``AVX-512`` specific implementations of + some file to be used or not. What has been disabled is compiler feature to produce ``AVX-512`` + instructions from any source code. + + On DPDK v18.11 ``AVX-512`` is disabled for all ``GCC`` builds which reported to cause a performance + drop. + + On DPDK v19.02 ``AVX-512`` disable scope is reduced to ``GCC`` and ``binutils version 2.30`` based + on information accured from the GCC community defect. + +**Reason**: + Generated ``AVX-512`` code cause crash: + https://bugs.dpdk.org/show_bug.cgi?id=97 + https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88096 + +**Resolution/Workaround**: + * Update ``binutils`` to newer version than ``2.30``. + + OR + + * Use different compiler, like ``clang`` for this case. + +**Affected Environment/Platform**: + ``GCC`` and ``binutils version 2.30``. + +**Driver/Module**: + ALL. diff --git a/mk/rte.cpuflags.mk b/mk/rte.cpuflags.mk index 2129510c2..eee4868b2 100644 --- a/mk/rte.cpuflags.mk +++ b/mk/rte.cpuflags.mk @@ -97,8 +97,8 @@ 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 8dbd4417e..ad3b68e63 100644 --- a/mk/toolchain/gcc/rte.toolchain-compat.mk +++ b/mk/toolchain/gcc/rte.toolchain-compat.mk @@ -47,6 +47,16 @@ 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,$(CURDIR)),) +$(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 = -- 2.11.0 --- Diff of the applied patch vs upstream commit (please double-check if non-empty: --- --- - 2019-03-08 09:46:41.889660902 -0800 +++ 0032-mk-fix-scope-of-disabling-AVX512F-support.patch 2019-03-08 09:46:40.143408000 -0800 @@ -1,8 +1,10 @@ -From a32ca9a4ebc1350ce48df0222decef95a72b742b Mon Sep 17 00:00:00 2001 +From e2e5744253733ce137e780699da00a627a25fc6a Mon Sep 17 00:00:00 2001 From: Ferruh Yigit Date: Mon, 14 Jan 2019 15:49:35 +0000 Subject: [PATCH] mk: fix scope of disabling AVX512F support +[ backported from upstream commit a32ca9a4ebc1350ce48df0222decef95a72b742b ] + 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. @@ -15,43 +17,21 @@ [2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88096 -Fixes: 8d07c82b239f ("mk: disable gcc AVX512F support") -Cc: stable@dpdk.org +Fixes: 1bc8541000ff ("mk: disable gcc AVX512F support") Signed-off-by: Ferruh Yigit Acked-by: Thomas Monjalon --- - config/meson.build | 8 ++++++++ doc/guides/rel_notes/known_issues.rst | 35 ++++++++++++++++++++++++++++++++ - doc/guides/rel_notes/release_19_02.rst | 15 ++++++++++++++ mk/rte.cpuflags.mk | 4 ++-- mk/toolchain/gcc/rte.toolchain-compat.mk | 10 +++++++++ - 5 files changed, 70 insertions(+), 2 deletions(-) + 3 files changed, 47 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/doc/guides/rel_notes/known_issues.rst b/doc/guides/rel_notes/known_issues.rst -index a1face9c1..358dfa321 100644 +index 3f6d8cb5f..fa0082137 100644 --- a/doc/guides/rel_notes/known_issues.rst +++ b/doc/guides/rel_notes/known_issues.rst -@@ -826,3 +826,38 @@ Kernel crash when hot-unplug igb_uio device while DPDK application is running +@@ -742,3 +742,38 @@ igb_uio can not be used when running l3fwd-power **Driver/Module**: ``igb_uio`` module. @@ -90,37 +70,11 @@ + +**Driver/Module**: + ALL. -diff --git a/doc/guides/rel_notes/release_19_02.rst b/doc/guides/rel_notes/release_19_02.rst -index 832ac8c2a..5a2f62ca9 100644 ---- a/doc/guides/rel_notes/release_19_02.rst -+++ b/doc/guides/rel_notes/release_19_02.rst -@@ -334,6 +334,21 @@ Known Issues - Also, make sure to start the actual text at the margin. - ========================================================= - -+* ``AVX-512`` support has been disabled for ``GCC`` builds when ``binutils 2.30`` -+ is detected [1] because of a crash [2]. This can affect ``native`` machine type -+ build targets on the platforms that support ``AVX512F`` like ``Intel Skylake`` -+ processors, and can cause a possible performance drop. The immediate workaround -+ is to use ``clang`` compiler on these platforms. -+ Initial workaround in DPDK v18.11 was to disable ``AVX-512`` support for ``GCC`` -+ completely, but based on information on defect submitted to GCC community [3], -+ issue has been identified as ``binutils 2.30`` issue. Since currently only GCC -+ generates ``AVX-512`` instructions, the scope is limited to ``GCC`` and -+ ``binutils 2.30`` -+ -+ - [1]: Commit ("mk: fix scope of disabling AVX512F support") -+ - [2]: https://bugs.dpdk.org/show_bug.cgi?id=97 -+ - [3]: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88096 -+ - - Tested Platforms - ---------------- diff --git a/mk/rte.cpuflags.mk b/mk/rte.cpuflags.mk -index c3291b17a..541211c61 100644 +index 2129510c2..eee4868b2 100644 --- a/mk/rte.cpuflags.mk +++ b/mk/rte.cpuflags.mk -@@ -69,8 +69,8 @@ ifneq ($(filter $(AUTO_CPUFLAGS),__AVX512F__),) +@@ -97,8 +97,8 @@ ifneq ($(filter $(AUTO_CPUFLAGS),__AVX512F__),) ifeq ($(CONFIG_RTE_ENABLE_AVX512),y) CPUFLAGS += AVX512F else @@ -132,10 +86,10 @@ endif endif diff --git a/mk/toolchain/gcc/rte.toolchain-compat.mk b/mk/toolchain/gcc/rte.toolchain-compat.mk -index 44904295c..dbddc986e 100644 +index 8dbd4417e..ad3b68e63 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) +@@ -47,6 +47,16 @@ 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)