Re: [dpdk-dev] [PATCH v1] app/testpmd: optimized MAC swap by using neon intrinsics

["Ruifeng Wang (Arm Technology China)" <Ruifeng.Wang@arm.com>]

Regards,
/Ruifeng

> -----Original Message-----
> From: Jerin Jacob Kollanukkaran <jerinj@marvell.com>
> Sent: 2019年3月11日 22:17
> To: Ruifeng Wang (Arm Technology China) <Ruifeng.Wang@arm.com>;
> jingjing.wu@intel.com; bernard.iremonger@intel.com;
> wenzhuo.lu@intel.com
> Cc: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>; nd
> <nd@arm.com>; hemant.agrawal@nxp.com; dev@dpdk.org
> Subject: Re: [PATCH v1] app/testpmd: optimized MAC swap by using neon
> intrinsics
> 
> On Mon, 2019-03-11 at 16:14 +0800, Ruifeng Wang wrote:
> > -------------------------------------------------------------------
> > ---
> > Improved MAC swap performance for ARM platform.
> > The improvement was achieved by using neon intrinsics to save CPU
> > cycles and doing swap for four packets at a time.
> > The optimization had 15% - 20% throughput boost in testpmd MAC swap
> > mode.
> >
> > Signed-off-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > Reviewed-by: Gavin Hu <gavin.hu@arm.com>
> > Reviewed-by: Phil Yang <phil.yang@arm.com>
> > ---
> >  app/test-pmd/macswap.c      |  4 +-
> >  app/test-pmd/macswap_neon.h | 93
> > +++++++++++++++++++++++++++++++++++++++++++++
> >  2 files changed, 96 insertions(+), 1 deletion(-)  create mode 100644
> > app/test-pmd/macswap_neon.h
> >
> > diff --git a/app/test-pmd/macswap.c b/app/test-pmd/macswap.c
> >
> > +static inline void
> > +do_macswap(struct rte_mbuf *pkts[], uint16_t nb,
> > +		struct rte_port *txp)
> > +{
> > +	struct ether_hdr *eth_hdr[4];
> > +	struct rte_mbuf *mb[4];
> > +	uint64_t ol_flags;
> > +	int i;
> > +	int r;
> > +	uint8x16_t v0, v1, v2, v3;
> > +	/**
> > +	 * Index map be used to shuffle the 16 bytes.
> > +	 * byte 0-5 will be swapped with byte 6-11.
> > +	 * byte 12-15 will keep unchanged.
> > +	 */
> > +	uint8x16_t idx_map = {6, 7, 8, 9, 10, 11, 0, 1, 2, 3, 4, 5,
> > +				12, 13, 14, 15};
> 
> Nit: I think, we can make it as "const uint8x16_t idx_map".
> 
> Other than that it looks good to me.
> Regarding the performance, I have tested with two SoCs.
> 
> octeontx: +13% improvement
> octeontx2: +46% improvement
> 
> 
> Acked-by: Jerin Jacob <jerinj@marvell.com>
> 
Thanks Jerin for your test and data.
The code change will be included in v2.