[dpdk-dev] [PATCH v3 5/7] examples/l3fwd: add neon support for l3fwd

[Jianbo Liu]

On 11 May 2017 at 18:27, Sekhar, Ashwin <Ashwin.Sekhar at cavium.com> wrote:
> On Thu, 2017-05-11 at 18:01 +0800, Jianbo Liu wrote:
>> On 11 May 2017 at 17:49, Sekhar, Ashwin <Ashwin.Sekhar at cavium.com>
>> wrote:
>> >
>> > Hi Jianbo,
>> >
>> > Thanks for v3. Small compilation error. See inline comment.
>> > Otherwise
>> > it looks fine.
>> >
>> > On Thu, 2017-05-11 at 17:25 +0800, Jianbo Liu wrote:
>> > >
>> > > Use ARM NEON intrinsics to accelerate l3 fowarding.
>> > >
>> > > Signed-off-by: Jianbo Liu <jianbo.liu at linaro.org>
>> > > ---
>> > [...]
>> >
>> > >
>> > > +/**
>> > > + * Process one packet:
>> > > + * Update source and destination MAC addresses in the ethernet
>> > > header.
>> > > + * Perform RFC1812 checks and updates for IPV4 packets.
>> > > + */
>> > > +static inline void
>> > > +process_packet(struct rte_mbuf *pkt, uint16_t *dst_port)
>> > > +{
>> > > +     struct ether_hdr *eth_hdr;
>> > > +     uint32x4_t te, ve;
>> > > +
>> > > +     eth_hdr = rte_pktmbuf_mtod(pkt, struct ether_hdr *);
>> > > +
>> > > +     te = vld1q_u32((uint32_t *)eth_hdr);
>> > > +     ve = vreinterpretq_u32_s32(val_eth[dst_port[0]]);
>> > > +
>> > > +
>> > > +     rfc1812_process((struct ipv4_hdr *)(eth_hdr + 1), dst_port,
>> > > +                     pkt->packet_type);
>> > > +
>> > > +     ve = vcopyq_lane_u32(ve, 3, te, 3);
>> > Compilation error here. This should be vcopyq_laneq_u32 (Extra q
>> > after
>> > lane)
>> No vcopyq_laneq_u32 in arm_neon.h of my environment. I thought it's a
>> typo so I changed.
>>
>> my gcc version 4.8.5 20150623 (Red Hat 4.8.5-11) (GCC).
>> What about yours?
>>
> I am using GCC 7.1. No error with this version.
>
> Also to cross check I tried the following versions as well which all
> gave compilation errors.
>  * gcc (Ubuntu/Linaro 4.9.2-10ubuntu13) 4.9.2
>  * gcc 5.3
>  * GCC 6.3
>
> So looks like vcopyq_laneq_u32 is not supported in GCC versions < 7.
> We can add a wrapper for the same in
> ./lib/librte_eal/common/include/arch/arm/rte_vect.h for gcc versions <
> 7.

OK

>
> But I think we can defer this activity. Because I have some other
> patches, which moves around the definition of GCC_VERSION, and adds
> wrappers for some unsupported instrinsics. Please see below.
> http://dpdk.org/dev/patchwork/patch/24161/
> http://dpdk.org/dev/patchwork/patch/24162/
>
> I think we can add the vcopyq_laneq_u32 change and the wrapper for the
> same after the above patches are merged.
>

I'll add that after your patches are ready.

> And FYI - Documentation for the vcopyq_laneq_u32 can be found in below
> document.
> http://infocenter.arm.com/help/topic/com.arm.doc.ihi0073a/IHI0
> 073A_arm_neon_intrinsics_ref.pdf
>

Thanks!

>> >
>> > >
>> > > +     vst1q_u32((uint32_t *)eth_hdr, ve);
>> > > +}
>> > > +
>> > [...]