app/testpmd: optimize MAC swap for Arm

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>
Acked-by: Jerin Jacob <jerinj@marvell.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>

diff --git a/app/test-pmd/macswap.c b/app/test-pmd/macswap.c
index cbb41b7..71af916 100644 (file)
--- a/app/test-pmd/macswap.c
+++ b/app/test-pmd/macswap.c
@@ -66,8 +66,10 @@
 #include <rte_flow.h>
 
 #include "testpmd.h"
-#ifdef RTE_ARCH_X86
+#if defined(RTE_ARCH_X86)
 #include "macswap_sse.h"
+#elif defined(RTE_MACHINE_CPUFLAG_NEON)
+#include "macswap_neon.h"
 #else
 #include "macswap.h"
 #endif

diff --git a/app/test-pmd/macswap_neon.h b/app/test-pmd/macswap_neon.h
new file mode 100644 (file)
index 0000000..bdf416a
--- /dev/null
+++ b/app/test-pmd/macswap_neon.h
@@ -0,0 +1,97 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2019 Arm Limited
+ *
+ * Copyright(c) 2019 Intel Corporation
+ *
+ * Derived do_macswap implementation from app/test-pmd/macswap_sse.h
+ */
+
+#ifndef _MACSWAP_NEON_H_
+#define _MACSWAP_NEON_H_
+
+#include "macswap_common.h"
+#include "rte_vect.h"
+
+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.
+        */
+       const uint8x16_t idx_map = {6, 7, 8, 9, 10, 11, 0, 1, 2, 3, 4, 5,
+                               12, 13, 14, 15};
+
+       ol_flags = ol_flags_init(txp->dev_conf.txmode.offloads);
+       vlan_qinq_set(pkts, nb, ol_flags,
+                       txp->tx_vlan_id, txp->tx_vlan_id_outer);
+
+       i = 0;
+       r = nb;
+
+       while (r >= 4) {
+               if (r >= 8) {
+                       rte_prefetch0(rte_pktmbuf_mtod(pkts[i + 4], void *));
+                       rte_prefetch0(rte_pktmbuf_mtod(pkts[i + 5], void *));
+                       rte_prefetch0(rte_pktmbuf_mtod(pkts[i + 6], void *));
+                       rte_prefetch0(rte_pktmbuf_mtod(pkts[i + 7], void *));
+               }
+
+               mb[0] = pkts[i++];
+               eth_hdr[0] = rte_pktmbuf_mtod(mb[0], struct ether_hdr *);
+
+               mb[1] = pkts[i++];
+               eth_hdr[1] = rte_pktmbuf_mtod(mb[1], struct ether_hdr *);
+
+               mb[2] = pkts[i++];
+               eth_hdr[2] = rte_pktmbuf_mtod(mb[2], struct ether_hdr *);
+
+               mb[3] = pkts[i++];
+               eth_hdr[3] = rte_pktmbuf_mtod(mb[3], struct ether_hdr *);
+
+               v0 = vld1q_u8((uint8_t const *)eth_hdr[0]);
+               v1 = vld1q_u8((uint8_t const *)eth_hdr[1]);
+               v2 = vld1q_u8((uint8_t const *)eth_hdr[2]);
+               v3 = vld1q_u8((uint8_t const *)eth_hdr[3]);
+
+               v0 = vqtbl1q_u8(v0, idx_map);
+               v1 = vqtbl1q_u8(v1, idx_map);
+               v2 = vqtbl1q_u8(v2, idx_map);
+               v3 = vqtbl1q_u8(v3, idx_map);
+
+               vst1q_u8((uint8_t *)eth_hdr[0], v0);
+               vst1q_u8((uint8_t *)eth_hdr[1], v1);
+               vst1q_u8((uint8_t *)eth_hdr[2], v2);
+               vst1q_u8((uint8_t *)eth_hdr[3], v3);
+
+               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;
+       }
+
+       for ( ; i < nb; i++) {
+               if (i < nb - 1)
+                       rte_prefetch0(rte_pktmbuf_mtod(pkts[i+1], void *));
+               mb[0] = pkts[i];
+               eth_hdr[0] = rte_pktmbuf_mtod(mb[0], struct ether_hdr *);
+
+               /* Swap dest and src mac addresses. */
+               v0 = vld1q_u8((uint8_t const *)eth_hdr[0]);
+               v0 = vqtbl1q_u8(v0, idx_map);
+               vst1q_u8((uint8_t *)eth_hdr[0], v0);
+
+               mbuf_field_set(mb[0], ol_flags);
+       }
+}
+
+#endif /* _MACSWAP_NEON_H_ */

diff --git a/doc/guides/rel_notes/release_19_05.rst b/doc/guides/rel_notes/release_19_05.rst
index 61a2c73..6f76de3 100644 (file)
--- a/doc/guides/rel_notes/release_19_05.rst
+++ b/doc/guides/rel_notes/release_19_05.rst
@@ -91,6 +91,11 @@ New Features
 
   * Added promiscuous mode support.
 
+* **Updated the testpmd application.**
+
+  Improved testpmd application performance on ARM platform. For ``macswap``
+  forwarding mode, NEON intrinsics were used to do swap to save CPU cycles.
+
 
 Removed Items
 -------------