From patchwork Tue Nov 20 12:50:31 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ferruh Yigit X-Patchwork-Id: 48205 X-Patchwork-Delegate: thomas@monjalon.net Return-Path: X-Original-To: patchwork@dpdk.org Delivered-To: patchwork@dpdk.org Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 1DD862BD5; Tue, 20 Nov 2018 13:50:40 +0100 (CET) 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) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Nov 2018 04:50:36 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,257,1539673200"; d="scan'208";a="110065317" Received: from silpixa00399752.ir.intel.com (HELO silpixa00399752.ger.corp.intel.com) ([10.237.222.212]) by orsmga002.jf.intel.com with ESMTP; 20 Nov 2018 04:50:34 -0800 From: Ferruh Yigit To: John McNamara , Marko Kovacevic Cc: dev@dpdk.org, Ferruh Yigit , Bruce Richardson , Konstantin Ananyev Date: Tue, 20 Nov 2018 12:50:31 +0000 Message-Id: <20181120125031.3390-1-ferruh.yigit@intel.com> X-Mailer: git-send-email 2.17.2 Subject: [dpdk-dev] [PATCH] doc: announce disabling GCC AVX512F as known issue X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list 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 Acked-by: John McNamara --- 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 ----------------