From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ferruh Yigit Subject: [PATCH] doc: announce disabling GCC AVX512F as known issue Date: Tue, 20 Nov 2018 12:50:31 +0000 Message-ID: <20181120125031.3390-1-ferruh.yigit@intel.com> Cc: dev@dpdk.org, Ferruh Yigit , Bruce Richardson , Konstantin Ananyev To: John McNamara , Marko Kovacevic Return-path: Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by dpdk.org (Postfix) with ESMTP id B68A829D2 for ; Tue, 20 Nov 2018 13:50:37 +0100 (CET) List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Document that AVX512F has been disabled for GCC builds [1] and document its potential implications on release notes, known issue section. [1] Commit 8d07c82b239f ("mk: disable gcc AVX512F support") Signed-off-by: Ferruh Yigit --- doc/guides/rel_notes/release_18_11.rst | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/doc/guides/rel_notes/release_18_11.rst b/doc/guides/rel_notes/release_18_11.rst index 32ff0e5c0..1116aff57 100644 --- a/doc/guides/rel_notes/release_18_11.rst +++ b/doc/guides/rel_notes/release_18_11.rst @@ -567,6 +567,17 @@ Known Issues * IBM Power8 is not supported by this release of DPDK. IBM Power9 is supported. +* ``AVX-512`` support has been disabled for ``GCC`` builds [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. + Issue has been identified as a GCC defect and reported to GCC community [3]. Further + actions will be taken based on the GCC defect result. + + [1]: Commit 8d07c82b239f ("mk: disable gcc 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 ---------------- -- 2.17.2