From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jianbo Liu <Jianbo.Liu@arm.com>
Subject: Re: [PATCH v2] examples/l3fwd: fix aliasing in port
 grouping
Date: Mon, 6 Nov 2017 16:18:06 +0800
Message-ID: <20171106081805.GA15773@arm.com>
References: <20171103104351.30181-1-gprathyusha@caviumnetworks.com>
 <20171106042945.GA4073@jerin>
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Cc: Guduri Prathyusha <gprathyusha@caviumnetworks.com>,
 tomasz.kantecki@intel.com, guduriprathyusha@gmail.com,
 konstantin.ananyev@intel.com, dev@dpdk.org
To: Jerin Jacob <jerin.jacob@caviumnetworks.com>
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The 11/06/2017 09:59, Jerin Jacob wrote:
> -----Original Message-----
> > Date: Fri,  3 Nov 2017 16:13:51 +0530
> > From: Guduri Prathyusha <gprathyusha@caviumnetworks.com>
> > To: tomasz.kantecki@intel.com
> > CC: Jianbo.Liu@arm.com, guduriprathyusha@gmail.com,
> >  konstantin.ananyev@intel.com, dev@dpdk.org, Guduri Prathyusha
> >  <gprathyusha@caviumnetworks.com>
> > Subject: [dpdk-dev] [PATCH v2] examples/l3fwd: fix aliasing in port gro=
uping
> > X-Mailer: git-send-email 2.14.1
> >
> > With -f-strict-aliasing enabled by default from -O2, gcc > 5.x gives
> > undefined behavior in port_groupx4 in ARM. 'pn' and 'pnum' are
> > two different pointers pointing to same chunk of memory and
> > with -f-strict-aliasing the pointers are assumed to be pointing to
> > different memory and compiler reorders instructions that depend on
> > pnum and pn. This breaks port grouping algorithm.
> >
> > This patch eliminates the above problem by introducing a compiler
> > barrier between the instructions that depend on pnum, pn and lp.
> >
> > Fixes: 569b290cdb36 ("examples/l3fwd: add NEON implementation")
> >
> > Signed-off-by: Guduri Prathyusha <gprathyusha@caviumnetworks.com>
>
> Acked-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>
>

Acked-by: Jianbo Liu <jianbo.liu@arm.com>
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