From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by dpdk.org (Postfix) with ESMTP id 48B4D29C6 for ; Mon, 4 Apr 2016 17:52:53 +0200 (CEST) Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga101.fm.intel.com with ESMTP; 04 Apr 2016 08:52:02 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,441,1455004800"; d="scan'208";a="78780870" Received: from irsmsx106.ger.corp.intel.com ([163.33.3.31]) by fmsmga004.fm.intel.com with ESMTP; 04 Apr 2016 08:52:03 -0700 Received: from irsmsx111.ger.corp.intel.com (10.108.20.4) by IRSMSX106.ger.corp.intel.com (163.33.3.31) with Microsoft SMTP Server (TLS) id 14.3.248.2; Mon, 4 Apr 2016 16:51:30 +0100 Received: from irsmsx108.ger.corp.intel.com ([169.254.11.13]) by irsmsx111.ger.corp.intel.com ([169.254.2.127]) with mapi id 14.03.0248.002; Mon, 4 Apr 2016 16:51:30 +0100 From: "De Lara Guarch, Pablo" To: "Ananyev, Konstantin" , "Kulasek, TomaszX" CC: "dev@dpdk.org" Thread-Topic: [dpdk-dev] [PATCH] examples/l3fwd: fix segfault with gcc 5.x Thread-Index: AQHRjoC9Ajm7Ntg020C/L3qRoeP9Ip954UAAgAAUQSA= Date: Mon, 4 Apr 2016 15:51:30 +0000 Message-ID: References: <1459781123-7556-1-git-send-email-tomaszx.kulasek@intel.com> <2601191342CEEE43887BDE71AB97725836B2DF1A@irsmsx105.ger.corp.intel.com> In-Reply-To: <2601191342CEEE43887BDE71AB97725836B2DF1A@irsmsx105.ger.corp.intel.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-titus-metadata-40: eyJDYXRlZ29yeUxhYmVscyI6IiIsIk1ldGFkYXRhIjp7Im5zIjoiaHR0cDpcL1wvd3d3LnRpdHVzLmNvbVwvbnNcL0ludGVsMyIsImlkIjoiZDkyMzA0YmQtYTkyNi00ODkxLTk2MGQtMGI4NmMxYWJhOWQ4IiwicHJvcHMiOlt7Im4iOiJDVFBDbGFzc2lmaWNhdGlvbiIsInZhbHMiOlt7InZhbHVlIjoiQ1RQX0lDIn1dfV19LCJTdWJqZWN0TGFiZWxzIjpbXSwiVE1DVmVyc2lvbiI6IjE1LjkuNi42IiwiVHJ1c3RlZExhYmVsSGFzaCI6ImMxaHZwMmJrejdzUUhUa0FVbHZ0N2habTFvT1E0cFR3dFZoNzNsYmo5NWM9In0= x-ctpclassification: CTP_IC x-originating-ip: [163.33.239.181] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [dpdk-dev] [PATCH] examples/l3fwd: fix segfault with gcc 5.x X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 04 Apr 2016 15:52:53 -0000 > -----Original Message----- > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Ananyev, > Konstantin > Sent: Monday, April 04, 2016 4:35 PM > To: Kulasek, TomaszX > Cc: dev@dpdk.org > Subject: Re: [dpdk-dev] [PATCH] examples/l3fwd: fix segfault with gcc 5.x >=20 > Hi Tomasz, >=20 > > -----Original Message----- > > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Tomasz Kulasek > > Sent: Monday, April 04, 2016 3:45 PM > > To: dev@dpdk.org > > Subject: [dpdk-dev] [PATCH] examples/l3fwd: fix segfault with gcc 5.x > > > > It seems that with gcc >5.x and -O2/-O3 optimization breaks packet > grouping > > algorithm. > > > > When last packet pointer "lp" and "pnum->u64" buffer points the same > > memory buffer, high optimization can cause unpredictable results. It se= ems > > that assignment of precalculated group sizes may interfere with > > initialization of new group size when lp points value inside current gr= oup > > and didn't should be changed. > > > > With gcc >5.x and optimization we cannot be sure which assignment will = be > > done first, so the group size can be counted incorrectly. > > > > This patch eliminates intersection of assignment of initial group size > > (lp[0] =3D 1) and precalculated group sizes when gptbl[v].idx < 4. > > > > Fixes: 94c54b4158d5 ("examples/l3fwd: rework exact-match") > > > > Signed-off-by: Tomasz Kulasek > > --- > > examples/l3fwd/l3fwd_sse.h | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/examples/l3fwd/l3fwd_sse.h b/examples/l3fwd/l3fwd_sse.h > > index f9cf50a..1afa1f0 100644 > > --- a/examples/l3fwd/l3fwd_sse.h > > +++ b/examples/l3fwd/l3fwd_sse.h > > @@ -283,9 +283,9 @@ port_groupx4(uint16_t pn[FWDSTEP + 1], uint16_t > *lp, __m128i dp1, __m128i dp2) > > > > /* if dest port value has changed. */ > > if (v !=3D GRPMSK) { > > - lp =3D pnum->u16 + gptbl[v].idx; > > - lp[0] =3D 1; > > pnum->u64 =3D gptbl[v].pnum; > > + pnum->u16[FWDSTEP] =3D 1; >=20 > Hmm, but FWDSTEP and gptbl[v].idx are not always equal. > Actually could you explain a bit more - what exactly is reordered by gcc = 5.x, > and how to reproduce it? > i.e what sequence of input packets will trigger an error? Hi Konstantin, I could see the issue when having two flows in one port, one going to port = 0 and the other to port 1 (using Exact Match). There is no issue when there is just one flow per port, using an older gcc = version (< 5.0) or using O0/O1 (and of course, using LPM). Pablo > Konstantin >=20 > > + lp =3D pnum->u16 + gptbl[v].idx; > > } > > > > return lp; > > -- > > 1.7.9.5