app/testpmd: move offload update

Moving the offload flag update from end to start of the loop,
helps to reduce L1 or L2 cache evictions and amortize shuffle.
This helps to improve RX packet in mac-swap processing.

Test Result:
 * Platform: AMD EPYC 9554 @3.1GHz, no boost
 * Test scenarios: TEST-PMD 64B IO vs MAC-SWAP
 * NIC: broadcom P2100: loopback 2*100Gbps

 <mode : Mpps Ingress: Mpps Egress>
 ------------------------------------------------
  - MAC-SWAP original: 45.75 : 43.8
  - MAC-SWAP register mod: 45.73 : 44.83
  - MAC-SWAP register+ofl modified: 46.36 : 44.79

Signed-off-by: Vipin Varghese <[email protected]>
Acked-by: Ferruh Yigit <[email protected]>

Author: vipinamd

app/test-pmd/macswap_sse.h

@@ -45,19 +45,22 @@ do_macswap(struct rte_mbuf *pkts[], uint16_t nb,
 		mb[0] = pkts[i++];
 		eth_hdr[0] = rte_pktmbuf_mtod(mb[0], struct rte_ether_hdr *);
 		addr0 = _mm_loadu_si128((__m128i *)eth_hdr[0]);
+		mbuf_field_set(mb[0], ol_flags);
 
 		mb[1] = pkts[i++];
 		eth_hdr[1] = rte_pktmbuf_mtod(mb[1], struct rte_ether_hdr *);
 		addr1 = _mm_loadu_si128((__m128i *)eth_hdr[1]);
-
+		mbuf_field_set(mb[1], ol_flags);
 
 		mb[2] = pkts[i++];
 		eth_hdr[2] = rte_pktmbuf_mtod(mb[2], struct rte_ether_hdr *);
 		addr2 = _mm_loadu_si128((__m128i *)eth_hdr[2]);
+		mbuf_field_set(mb[2], ol_flags);
 
 		mb[3] = pkts[i++];
 		eth_hdr[3] = rte_pktmbuf_mtod(mb[3], struct rte_ether_hdr *);
 		addr3 = _mm_loadu_si128((__m128i *)eth_hdr[3]);
+		mbuf_field_set(mb[3], ol_flags);
 
 		addr0 = _mm_shuffle_epi8(addr0, shfl_msk);
 		addr1 = _mm_shuffle_epi8(addr1, shfl_msk);
@@ -69,10 +72,6 @@ do_macswap(struct rte_mbuf *pkts[], uint16_t nb,
 		_mm_storeu_si128((__m128i *)eth_hdr[2], addr2);
 		_mm_storeu_si128((__m128i *)eth_hdr[3], addr3);
 
-		mbuf_field_set(mb[0], ol_flags);
-		mbuf_field_set(mb[1], ol_flags);
-		mbuf_field_set(mb[2], ol_flags);
-		mbuf_field_set(mb[3], ol_flags);
 		r -= 4;
 	}
 
@@ -84,10 +83,10 @@ do_macswap(struct rte_mbuf *pkts[], uint16_t nb,
 
 		/* Swap dest and src mac addresses. */
 		addr0 = _mm_loadu_si128((__m128i *)eth_hdr[0]);
+		mbuf_field_set(mb[0], ol_flags);
+
 		addr0 = _mm_shuffle_epi8(addr0, shfl_msk);
 		_mm_storeu_si128((__m128i *)eth_hdr[0], addr0);
-
-		mbuf_field_set(mb[0], ol_flags);
 	}
 }