From: Guduri Prathyusha <gprathyusha@caviumnetworks.com>
To: Jianbo Liu <Jianbo.Liu@arm.com>
Cc: dev@dpdk.org, tomasz.kantecki@intel.com, guduriprathyusha@gmail.com
Subject: Re: [dpdk-dev] [PATCH] examples/l3fwd: fix NEON instructions
Date: Mon, 30 Oct 2017 12:44:38 +0530 [thread overview]
Message-ID: <20171030071436.GA1145@cavium.com> (raw)
In-Reply-To: <20171030062623.GA26958@arm.com>
On Mon, Oct 30, 2017 at 02:27:09PM +0800, Jianbo Liu wrote:
> The 10/29/2017 13:18, Guduri Prathyusha wrote:
> > To group consecutive packets with same destination port in bursts of 4
> > neon intrinsic data types dp1 and dp2 are calculated such that if
> > dst_port[]={a,b,c,d,e,f,g,h,i...} dp1 should contain: <a,b,c,d> and
> > dp2 should contain: <b,c,d,e> in the first iteration. dp1 should
> > be <e,f,g,h> and dp2 should be <f,g,h,i> in the next iteration. dp2 in
> > the last iteration should be <w,x,y,y>.
> >
> > Whereas the existing code incorrectly calculates dp1 as <d,e,f,g> from
> > second iteration and thus incorrect calculation of dp2 as <d,e,f,f>
> > in the last iteration.
> >
> > This patch fixes the incorrect ARM NEON instructions on dp1 and dp2.
> >
> > Fixes: 569b290cdb36 ("examples/l3fwd: add NEON implementation")
> >
> > Signed-off-by: Guduri Prathyusha <gprathyusha@caviumnetworks.com>
> > ---
> > examples/l3fwd/l3fwd_neon.h | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/examples/l3fwd/l3fwd_neon.h b/examples/l3fwd/l3fwd_neon.h
> > index 42d50d3c2..1eace4e03 100644
> > --- a/examples/l3fwd/l3fwd_neon.h
> > +++ b/examples/l3fwd/l3fwd_neon.h
> > @@ -192,13 +192,13 @@ send_packets_multi(struct lcore_conf *qconf, struct rte_mbuf **pkts_burst,
> > * dp1:
> > * <d[j], d[j+1], d[j+2], d[j+3], ... >
> > */
> > - dp1 = vextq_u16(dp1, dp1, FWDSTEP - 1);
> > + dp1 = vextq_u16(dp2, vdupq_n_u16(0), FWDSTEP - 1);
> > }
> >
> > /*
> > * dp2: <d[j-3], d[j-2], d[j-1], d[j-1], ... >
> > */
> > - dp2 = vextq_u16(dp1, dp1, 1);
> > + dp2 = vextq_u16(dp1, vdupq_n_u16(0), 1);
>
> Sorry, I don't think you need to change this line. Please ignore my
> comment about it in the last email.
>
Thanks for the quick review. dp1 changed as you said and leaving dp2 as
is solves the issue. Will spin a v2 with only changing dp1.
Prathyusha
> > dp2 = vsetq_lane_u16(vgetq_lane_u16(dp2, 2), dp2, 3);
> > lp = port_groupx4(&pnum[j - FWDSTEP], lp, dp1, dp2);
> >
> > --
> > 2.14.1
> >
>
> --
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prev parent reply other threads:[~2017-10-30 7:15 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-29 7:48 Guduri Prathyusha
2017-10-29 8:24 ` Guduri Prathyusha
2017-10-30 5:59 ` Jianbo Liu
2017-10-30 6:27 ` Jianbo Liu
2017-10-30 7:14 ` Guduri Prathyusha [this message]
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