From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 1485DA0A0C for ; Mon, 19 Jul 2021 12:04:34 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 046B0410EE; Mon, 19 Jul 2021 12:04:34 +0200 (CEST) Received: from sender11-of-o51.zoho.eu (sender11-of-o51.zoho.eu [31.186.226.237]) by mails.dpdk.org (Postfix) with ESMTP id D35234003E; Mon, 19 Jul 2021 12:04:31 +0200 (CEST) ARC-Seal: i=1; a=rsa-sha256; t=1626689067; cv=none; d=zohomail.eu; s=zohoarc; b=fkKuldJ60L0OBIt+yW/Kp9Ro4pW/lI5x3iCG4Uo5LMOiNTJh+PNNMTCV1DLGGOjvtYJglMFk16NVT3F0AG1ejF72A82T0ys3VUOgJ3aDJUk7bqKGaEzYj5SM/ZAsMssvcSUfcZRHyqSTAInc3E0zkWSOWK+NK/7mAXIv65H+RkY= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.eu; s=zohoarc; t=1626689067; h=Content-Type:Cc:Date:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:To; bh=rlksXiD8Z8JxsEhYWeTYyAOlWokXtuppuNKkOlUaySk=; b=ODpcEbsxQoaIJZEseVX75uATVoOV7J5KjFh+uDiu7peOcvG8kM2a4tp7hH2OqBX2e0v902OOdpjoRcOGCkoIsCfny7NzE0iIirCVxkDKcyMxVKN+MROX+9BRjAPJvyQ/wP0UTjCs3c7qWf1nEmNsZ9PV0J9KqbUN8RzHacB6YtA= ARC-Authentication-Results: i=1; mx.zohomail.eu; spf=pass smtp.mailfrom=liangma@liangbit.com; dmarc=pass header.from= Received: from C02F33EJML85 (153.185.242.35.bc.googleusercontent.com [35.242.185.153]) by mx.zoho.eu with SMTPS id 1626689066716665.4090369008146; Mon, 19 Jul 2021 12:04:26 +0200 (CEST) Date: Mon, 19 Jul 2021 11:04:23 +0100 From: Liang Ma To: Bruce Richardson Cc: Stephen Hemminger , dev@dpdk.org, leyi.rong@intel.com, Liang Ma , stable@dpdk.org, Konstantin Ananyev Message-ID: References: <20210717170830.1736-1-liangma@liangbit.com> <20210717104849.2ec6526e@hermes.local> <20210717221304.GA45@DESKTOP-POQV63C.localdomain> <20210717180804.301f7876@hermes.local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ZohoMailClient: External Subject: Re: [dpdk-stable] [dpdk-dev] [PATCH] buildtools: Check GCC version to avoid GCC 6.3.0 avx512 bug X-BeenThere: stable@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: patches for DPDK stable branches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: stable-bounces@dpdk.org Sender: "stable" On Mon, Jul 19, 2021 at 09:38:14AM +0100, Bruce Richardson wrote: > On Sun, Jul 18, 2021 at 10:33:15AM +0100, Liang Ma wrote: > > On Sat, Jul 17, 2021 at 06:08:04PM -0700, Stephen Hemminger wrote: > > > On Sat, 17 Jul 2021 23:13:04 +0100 > > > Liang Ma wrote: > > > > > > > On Sat, Jul 17, 2021 at 10:48:49AM -0700, Stephen Hemminger wrote: > > > > > On Sat, 17 Jul 2021 18:08:30 +0100 > > > > > Liang Ma wrote: > > > > > > > > > > > From: Liang Ma > > > > > > > > > > > > GCC 6.3.0 has a known bug which related to _mm512_extracti64x4_epi64. > > > > > > Please reference https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82887 > > > > > > > > > > > > Some DPDK PMD avx512 version heavily use _mm512_extracti64x4_epi6, > > > > > > which casue building failure with debug buildtype. > > > > > > > > > > > > Therefore, it's helpful to disable avx512 for GCC 6.3.0 > > > > > > > > > > > > Bugzilla ID: 717 > > > > > > Fixes: e6a6a138919f (net/i40e: add AVX512 vector path) > > > > > > Fixes: 808a17b3c1e6 (net/ice: add Rx AVX512 offload path) > > > > > > Fixes: 4b64ccb328c9 (net/iavf: fix VLAN extraction in AVX512 path) > > > > > > Cc: stable@dpdk.org > > > > > > > > > > > > Reported-by: Liang Ma > > > > > > Signed-off-by: Liang Ma > > > > > > > > > > What distro still has GCC 6.3.0? > > > > For example Debian 9.x > > > > > > Ok, thanks. Is there a bug fix in Debian LTS yet? > > I look into https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82887, and > > find gcc community has no plan to backport fix. Hence, I don't think > > Debian LTS will have any fix for this. That's why I send out this patch. > > > Thanks for the report. However, rather than just disabling based on version > number, can we instead use a compile-time check for broken compiler. This > is what we did previously for other similar issues and it works better > because: > * removes the possibility of us missing a broken compiler version > * takes account of the possibility of a fix backport (even if we don't > expect one, it's best not to count it out) > > Looking at the bug report, it seems this issue could be detected directly > in meson using "cc.compiles" and the code snippet from the report. > > Regards, > /Bruce Many thanks for the suggestion. I will rework the patch with the suggested solution.