On 19/03/2020 14:22, Pavan Nikhilesh Bhagavatula wrote:
>> On 18/03/2020 21:35, jer...@marvell.com wrote:
>>> From: Pavan Nikhilesh <pbhagavat...@marvell.com>
>>>
>>> Add IPv4 lookup process function for ip4_lookup
>>> rte_node. This node performs LPM lookup using x86_64
>>> vector supported RTE_LPM API on every packet received
>>> and forwards it to a next node that is identified by
>>> lookup result.
>>>
>>> Signed-off-by: Pavan Nikhilesh <pbhagavat...@marvell.com>
>>> Signed-off-by: Nithin Dabilpuram <ndabilpu...@marvell.com>
>>> Signed-off-by: Kiran Kumar K <kirankum...@marvell.com>
>>> ---
>>> lib/librte_node/ip4_lookup.c | 245
>> +++++++++++++++++++++++++++++++++++
>>> 1 file changed, 245 insertions(+)
>>>
>>> diff --git a/lib/librte_node/ip4_lookup.c
>> b/lib/librte_node/ip4_lookup.c
>>> index d7fcd1158..c003e9c91 100644
>>> --- a/lib/librte_node/ip4_lookup.c
>>> +++ b/lib/librte_node/ip4_lookup.c
>>> @@ -264,6 +264,251 @@ ip4_lookup_node_process(struct rte_graph
>> *graph, struct rte_node *node,
>>> return nb_objs;
>>> }
>>>
>>> +#elif defined(RTE_ARCH_X86)
>>> +
>>> +/* X86 SSE */
>>> +static uint16_t
>>> +ip4_lookup_node_process(struct rte_graph *graph, struct rte_node
>> *node,
>>> + void **objs, uint16_t nb_objs)
>>> +{
>>> + struct rte_mbuf *mbuf0, *mbuf1, *mbuf2, *mbuf3, **pkts;
>>> + rte_edge_t next0, next1, next2, next3, next_index;
>>> + struct rte_ipv4_hdr *ipv4_hdr;
>>> + struct rte_ether_hdr *eth_hdr;
>>> + uint32_t ip0, ip1, ip2, ip3;
>>> + void **to_next, **from;
>>> + uint16_t last_spec = 0;
>>> + uint16_t n_left_from;
>>> + struct rte_lpm *lpm;
>>> + uint16_t held = 0;
>>> + uint32_t drop_nh;
>>> + rte_xmm_t dst;
>>> + __m128i dip; /* SSE register */
>>> + int rc, i;
>>> +
>>> + /* Speculative next */
>>> + next_index = RTE_NODE_IP4_LOOKUP_NEXT_REWRITE;
>>> + /* Drop node */
>>> + drop_nh =
>> ((uint32_t)RTE_NODE_IP4_LOOKUP_NEXT_PKT_DROP) << 16;
>>> +
>>> + /* Get socket specific LPM from ctx */
>>> + lpm = *((struct rte_lpm **)node->ctx);
>>> +
>>> + pkts = (struct rte_mbuf **)objs;
>>> + from = objs;
>>> + n_left_from = nb_objs;
>>
>> I doubt this initial prefetch of the first 4 packets has any benefit.
>
> Ack will remove in v2 for x86.
>
>>
>>> + if (n_left_from >= 4) {
>>> + for (i = 0; i < 4; i++) {
>>> + rte_prefetch0(rte_pktmbuf_mtod(pkts[i],
>>> + struct rte_ether_hdr
>> *) +
>>> + 1);
>>> + }
>>> + }
>>> +
>>> + /* Get stream for the speculated next node */
>>> + to_next = rte_node_next_stream_get(graph, node,
>> next_index, nb_objs);
>>
>> Suggest you don't reuse the hand-unrolling optimization from FD.io
>> VPP.
>> I have never found any performance benefit from them, and they
>> make the code unnecessarily verbose.
>>
>
> How would be take the benefit of rte_lpm_lookupx4 without unrolling the loop?.
> Also, in future if we are using rte_rib and fib with a CPU supporting wider
> SIMD we might
> need to unroll them further (AVX256 AND 512 currently rte_lpm_lookup uses
> only 128bit
> since it is only uses SSE extension).
Let the compiler do it for you, but using a constant vector length.
for (int i=0; i < 4; ++i) { ... }
>
>>
>>> + while (n_left_from >= 4) {
>>> + /* Prefetch next-next mbufs */
>>> + if (likely(n_left_from >= 11)) {
>>> + rte_prefetch0(pkts[8]);
>>> + rte_prefetch0(pkts[9]);
>>> + rte_prefetch0(pkts[10]);
>>> + rte_prefetch0(pkts[11]);
>>> + }
>>> +
>>> + /* Prefetch next mbuf data */
>>> + if (likely(n_left_from >= 7)) {
>>> + rte_prefetch0(rte_pktmbuf_mtod(pkts[4],
>>> + struct rte_ether_hdr
>> *) +
>>> + 1);
>>> + rte_prefetch0(rte_pktmbuf_mtod(pkts[5],
>>> + struct rte_ether_hdr
>> *) +
>>> + 1);
>>> + rte_prefetch0(rte_pktmbuf_mtod(pkts[6],
>>> + struct rte_ether_hdr
>> *) +
>>> + 1);
>>> + rte_prefetch0(rte_pktmbuf_mtod(pkts[7],
>>> + struct rte_ether_hdr
>> *) +
>>> + 1);
>>> + }
>>> +
>>> + mbuf0 = pkts[0];
>>> + mbuf1 = pkts[1];
>>> + mbuf2 = pkts[2];
>>> + mbuf3 = pkts[3];
>>> +
>>> + pkts += 4;
>>> + n_left_from -= 4;
>>> +
>>> + /* Extract DIP of mbuf0 */
>>> + eth_hdr = rte_pktmbuf_mtod(mbuf0, struct
>> rte_ether_hdr *);
>>> + ipv4_hdr = (struct rte_ipv4_hdr *)(eth_hdr + 1);
>>> + ip0 = ipv4_hdr->dst_addr;
>>> + /* Extract cksum, ttl as ipv4 hdr is in cache */
>>> + rte_node_mbuf_priv1(mbuf0)->cksum = ipv4_hdr-
>>> hdr_checksum;
>>> + rte_node_mbuf_priv1(mbuf0)->ttl = ipv4_hdr-
>>> time_to_live;
>>> +
>>> + /* Extract DIP of mbuf1 */
>>> + eth_hdr = rte_pktmbuf_mtod(mbuf1, struct
>> rte_ether_hdr *);
>>> + ipv4_hdr = (struct rte_ipv4_hdr *)(eth_hdr + 1);
>>> + ip1 = ipv4_hdr->dst_addr;
>>> + /* Extract cksum, ttl as ipv4 hdr is in cache */
>>> + rte_node_mbuf_priv1(mbuf1)->cksum = ipv4_hdr-
>>> hdr_checksum;
>>> + rte_node_mbuf_priv1(mbuf1)->ttl = ipv4_hdr-
>>> time_to_live;
>>> +
>>> + /* Extract DIP of mbuf2 */
>>> + eth_hdr = rte_pktmbuf_mtod(mbuf2, struct
>> rte_ether_hdr *);
>>> + ipv4_hdr = (struct rte_ipv4_hdr *)(eth_hdr + 1);
>>> + ip2 = ipv4_hdr->dst_addr;
>>> + /* Extract cksum, ttl as ipv4 hdr is in cache */
>>> + rte_node_mbuf_priv1(mbuf2)->cksum = ipv4_hdr-
>>> hdr_checksum;
>>> + rte_node_mbuf_priv1(mbuf2)->ttl = ipv4_hdr-
>>> time_to_live;
>>> +
>>> + /* Extract DIP of mbuf3 */
>>> + eth_hdr = rte_pktmbuf_mtod(mbuf3, struct
>> rte_ether_hdr *);
>>> + ipv4_hdr = (struct rte_ipv4_hdr *)(eth_hdr + 1);
>>> + ip3 = ipv4_hdr->dst_addr;
>>> +
>>> + /* Prepare for lookup x4 */
>>> + dip = _mm_set_epi32(ip3, ip2, ip1, ip0);
>>> +
>>> + /* Byte swap 4 IPV4 addresses. */
>>> + const __m128i bswap_mask = _mm_set_epi8(
>>> + 12, 13, 14, 15, 8, 9, 10, 11, 4, 5, 6, 7, 0, 1, 2, 3);
>>> + dip = _mm_shuffle_epi8(dip, bswap_mask);
>>> +
>>> + /* Extract cksum, ttl as ipv4 hdr is in cache */
>>> + rte_node_mbuf_priv1(mbuf3)->cksum = ipv4_hdr-
>>> hdr_checksum;
>>> + rte_node_mbuf_priv1(mbuf3)->ttl = ipv4_hdr-
>>> time_to_live;
>>> +
>>> + /* Perform LPM lookup to get NH and next node */
>>> + rte_lpm_lookupx4(lpm, dip, dst.u32, drop_nh);
>>> +
>>> + /* Extract next node id and NH */
>>> + rte_node_mbuf_priv1(mbuf0)->nh = dst.u32[0] &
>> 0xFFFF;
>>> + next0 = (dst.u32[0] >> 16);
>>> +
>>> + rte_node_mbuf_priv1(mbuf1)->nh = dst.u32[1] &
>> 0xFFFF;
>>> + next1 = (dst.u32[1] >> 16);
>>> +
>>> + rte_node_mbuf_priv1(mbuf2)->nh = dst.u32[2] &
>> 0xFFFF;
>>> + next2 = (dst.u32[2] >> 16);
>>> +
>>> + rte_node_mbuf_priv1(mbuf3)->nh = dst.u32[3] &
>> 0xFFFF;
>>> + next3 = (dst.u32[3] >> 16);
>>> +
>>> + /* Enqueue four to next node */
>>> + rte_edge_t fix_spec =
>>> + (next_index ^ next0) | (next_index ^ next1) |
>>> + (next_index ^ next2) | (next_index ^ next3);
>>> +
>>> + if (unlikely(fix_spec)) {
>>> + /* Copy things successfully speculated till now
>> */
>>> + rte_memcpy(to_next, from, last_spec *
>> sizeof(from[0]));
>>> + from += last_spec;
>>> + to_next += last_spec;
>>> + held += last_spec;
>>> + last_spec = 0;
>>> +
>>> + /* Next0 */
>>> + if (next_index == next0) {
>>> + to_next[0] = from[0];
>>> + to_next++;
>>> + held++;
>>> + } else {
>>> + rte_node_enqueue_x1(graph, node,
>> next0,
>>> + from[0]);
>>> + }
>>> +
>>> + /* Next1 */
>>> + if (next_index == next1) {
>>> + to_next[0] = from[1];
>>> + to_next++;
>>> + held++;
>>> + } else {
>>> + rte_node_enqueue_x1(graph, node,
>> next1,
>>> + from[1]);
>>> + }
>>> +
>>> + /* Next2 */
>>> + if (next_index == next2) {
>>> + to_next[0] = from[2];
>>> + to_next++;
>>> + held++;
>>> + } else {
>>> + rte_node_enqueue_x1(graph, node,
>> next2,
>>> + from[2]);
>>> + }
>>> +
>>> + /* Next3 */
>>> + if (next_index == next3) {
>>> + to_next[0] = from[3];
>>> + to_next++;
>>> + held++;
>>> + } else {
>>> + rte_node_enqueue_x1(graph, node,
>> next3,
>>> + from[3]);
>>> + }
>>> +
>>> + from += 4;
>>> +
>>> + } else {
>>> + last_spec += 4;
>>> + }
>>> + }
>>> +
>>> + while (n_left_from > 0) {
>>> + uint32_t next_hop;
>>> +
>>> + mbuf0 = pkts[0];
>>> +
>>> + pkts += 1;
>>> + n_left_from -= 1;
>>> +
>>> + /* Extract DIP of mbuf0 */
>>> + eth_hdr = rte_pktmbuf_mtod(mbuf0, struct
>> rte_ether_hdr *);
>>> + ipv4_hdr = (struct rte_ipv4_hdr *)(eth_hdr + 1);
>>> + /* Extract cksum, ttl as ipv4 hdr is in cache */
>>> + rte_node_mbuf_priv1(mbuf0)->cksum = ipv4_hdr-
>>> hdr_checksum;
>>> + rte_node_mbuf_priv1(mbuf0)->ttl = ipv4_hdr-
>>> time_to_live;
>>> +
>>> + rc = rte_lpm_lookup(lpm, rte_be_to_cpu_32(ipv4_hdr-
>>> dst_addr),
>>> + &next_hop);
>>> + next_hop = (rc == 0) ? next_hop : drop_nh;
>>> +
>>> + rte_node_mbuf_priv1(mbuf0)->nh = next_hop &
>> 0xFFFF;
>>> + next0 = (next_hop >> 16);
>>> +
>>> + if (unlikely(next_index ^ next0)) {
>>> + /* Copy things successfully speculated till now
>> */
>>> + rte_memcpy(to_next, from, last_spec *
>> sizeof(from[0]));
>>> + from += last_spec;
>>> + to_next += last_spec;
>>> + held += last_spec;
>>> + last_spec = 0;
>>> +
>>> + rte_node_enqueue_x1(graph, node, next0,
>> from[0]);
>>> + from += 1;
>>> + } else {
>>> + last_spec += 1;
>>> + }
>>> + }
>>> +
>>> + /* !!! Home run !!! */
>>> + if (likely(last_spec == nb_objs)) {
>>> + rte_node_next_stream_move(graph, node,
>> next_index);
>>> + return nb_objs;
>>> + }
>>> +
>>> + held += last_spec;
>>> + /* Copy things successfully speculated till now */
>>> + rte_memcpy(to_next, from, last_spec * sizeof(from[0]));
>>> + rte_node_next_stream_put(graph, node, next_index, held);
>>> +
>>> + return nb_objs;
>>> +}
>>> +
>>> #else
>>>
>>> static uint16_t
>>>
