[dpdk-dev] [PATCH v13 7/7] app/testpmd: add forwarding engine for shared Rx queue

[Xueming Li <xuemingl@nvidia.com>]

To support shared Rx queue, this patch introduces dedicate forwarding
engine. The engine groups received packets by mbuf->port into sub-group,
updates stream statistics and simply frees packets.

Signed-off-by: Xueming Li <xuemingl@nvidia.com>
---
 app/test-pmd/meson.build                    |   1 +
 app/test-pmd/shared_rxq_fwd.c               | 115 ++++++++++++++++++++
 app/test-pmd/testpmd.c                      |   1 +
 app/test-pmd/testpmd.h                      |   1 +
 doc/guides/testpmd_app_ug/run_app.rst       |   5 +-
 doc/guides/testpmd_app_ug/testpmd_funcs.rst |   5 +-
 6 files changed, 126 insertions(+), 2 deletions(-)
 create mode 100644 app/test-pmd/shared_rxq_fwd.c

diff --git a/app/test-pmd/meson.build b/app/test-pmd/meson.build
index 1ad54caef2c..b5a0f7b6209 100644
--- a/app/test-pmd/meson.build
+++ b/app/test-pmd/meson.build
@@ -22,6 +22,7 @@ sources = files(
         'noisy_vnf.c',
         'parameters.c',
         'rxonly.c',
+        'shared_rxq_fwd.c',
         'testpmd.c',
         'txonly.c',
         'util.c',
diff --git a/app/test-pmd/shared_rxq_fwd.c b/app/test-pmd/shared_rxq_fwd.c
new file mode 100644
index 00000000000..da54a383fd5
--- /dev/null
+++ b/app/test-pmd/shared_rxq_fwd.c
@@ -0,0 +1,115 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright (c) 2021 NVIDIA Corporation & Affiliates
+ */
+
+#include <rte_ethdev.h>
+
+#include "testpmd.h"
+
+/*
+ * Rx only sub-burst forwarding.
+ */
+static void
+forward_rx_only(uint16_t nb_rx, struct rte_mbuf **pkts_burst)
+{
+	rte_pktmbuf_free_bulk(pkts_burst, nb_rx);
+}
+
+/**
+ * Get packet source stream by source port and queue.
+ * All streams of same shared Rx queue locates on same core.
+ */
+static struct fwd_stream *
+forward_stream_get(struct fwd_stream *fs, uint16_t port)
+{
+	streamid_t sm_id;
+	struct fwd_lcore *fc;
+	struct fwd_stream **fsm;
+	streamid_t nb_fs;
+
+	fc = fs->lcore;
+	fsm = &fwd_streams[fc->stream_idx];
+	nb_fs = fc->stream_nb;
+	for (sm_id = 0; sm_id < nb_fs; sm_id++) {
+		if (fsm[sm_id]->rx_port == port &&
+		    fsm[sm_id]->rx_queue == fs->rx_queue)
+			return fsm[sm_id];
+	}
+	return NULL;
+}
+
+/**
+ * Forward packet by source port and queue.
+ */
+static void
+forward_sub_burst(struct fwd_stream *src_fs, uint16_t port, uint16_t nb_rx,
+		  struct rte_mbuf **pkts)
+{
+	struct fwd_stream *fs = forward_stream_get(src_fs, port);
+
+	if (fs != NULL) {
+		fs->rx_packets += nb_rx;
+		forward_rx_only(nb_rx, pkts);
+	} else {
+		/* Source stream not found, drop all packets. */
+		src_fs->fwd_dropped += nb_rx;
+		while (nb_rx > 0)
+			rte_pktmbuf_free(pkts[--nb_rx]);
+	}
+}
+
+/**
+ * Forward packets from shared Rx queue.
+ *
+ * Source port of packets are identified by mbuf->port.
+ */
+static void
+forward_shared_rxq(struct fwd_stream *fs, uint16_t nb_rx,
+		   struct rte_mbuf **pkts_burst)
+{
+	uint16_t i, nb_sub_burst, port, last_port;
+
+	nb_sub_burst = 0;
+	last_port = pkts_burst[0]->port;
+	/* Locate sub-burst according to mbuf->port. */
+	for (i = 0; i < nb_rx - 1; ++i) {
+		rte_prefetch0(pkts_burst[i + 1]);
+		port = pkts_burst[i]->port;
+		if (i > 0 && last_port != port) {
+			/* Forward packets with same source port. */
+			forward_sub_burst(fs, last_port, nb_sub_burst,
+					  &pkts_burst[i - nb_sub_burst]);
+			nb_sub_burst = 0;
+			last_port = port;
+		}
+		nb_sub_burst++;
+	}
+	/* Last sub-burst. */
+	nb_sub_burst++;
+	forward_sub_burst(fs, last_port, nb_sub_burst,
+			  &pkts_burst[nb_rx - nb_sub_burst]);
+}
+
+static void
+shared_rxq_fwd(struct fwd_stream *fs)
+{
+	struct rte_mbuf *pkts_burst[nb_pkt_per_burst];
+	uint16_t nb_rx;
+	uint64_t start_tsc = 0;
+
+	get_start_cycles(&start_tsc);
+	nb_rx = rte_eth_rx_burst(fs->rx_port, fs->rx_queue, pkts_burst,
+				 nb_pkt_per_burst);
+	inc_rx_burst_stats(fs, nb_rx);
+	if (unlikely(nb_rx == 0))
+		return;
+	forward_shared_rxq(fs, nb_rx, pkts_burst);
+	get_end_cycles(fs, start_tsc);
+}
+
+struct fwd_engine shared_rxq_engine = {
+	.fwd_mode_name  = "shared_rxq",
+	.port_fwd_begin = NULL,
+	.port_fwd_end   = NULL,
+	.packet_fwd     = shared_rxq_fwd,
+};
diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c
index d76d298a4b9..6d5bbc82404 100644
--- a/app/test-pmd/testpmd.c
+++ b/app/test-pmd/testpmd.c
@@ -188,6 +188,7 @@ struct fwd_engine * fwd_engines[] = {
 #ifdef RTE_LIBRTE_IEEE1588
 	&ieee1588_fwd_engine,
 #endif
+	&shared_rxq_engine,
 	NULL,
 };
 
diff --git a/app/test-pmd/testpmd.h b/app/test-pmd/testpmd.h
index 9482dab3071..bf3669134aa 100644
--- a/app/test-pmd/testpmd.h
+++ b/app/test-pmd/testpmd.h
@@ -339,6 +339,7 @@ extern struct fwd_engine five_tuple_swap_fwd_engine;
 #ifdef RTE_LIBRTE_IEEE1588
 extern struct fwd_engine ieee1588_fwd_engine;
 #endif
+extern struct fwd_engine shared_rxq_engine;
 
 extern struct fwd_engine * fwd_engines[]; /**< NULL terminated array. */
 extern cmdline_parse_inst_t cmd_set_raw;
diff --git a/doc/guides/testpmd_app_ug/run_app.rst b/doc/guides/testpmd_app_ug/run_app.rst
index faa3efb902c..d23e0b6a7a2 100644
--- a/doc/guides/testpmd_app_ug/run_app.rst
+++ b/doc/guides/testpmd_app_ug/run_app.rst
@@ -258,6 +258,7 @@ The command line options are:
        tm
        noisy
        5tswap
+       shared-rxq
 
 *   ``--rss-ip``
 
@@ -399,7 +400,9 @@ The command line options are:
 
     Create queues in shared Rx queue mode if device supports.
     Shared Rx queues are grouped per X ports. X defaults to UINT32_MAX,
-    implies all ports join share group 1.
+    implies all ports join share group 1. Forwarding engine "shared-rxq"
+    should be used for shared Rx queues. This engine does Rx only and
+    update stream statistics accordingly.
 
 *   ``--eth-link-speed``
 
diff --git a/doc/guides/testpmd_app_ug/testpmd_funcs.rst b/doc/guides/testpmd_app_ug/testpmd_funcs.rst
index 6d127d9a7bc..78d23429c42 100644
--- a/doc/guides/testpmd_app_ug/testpmd_funcs.rst
+++ b/doc/guides/testpmd_app_ug/testpmd_funcs.rst
@@ -314,7 +314,7 @@ set fwd
 Set the packet forwarding mode::
 
    testpmd> set fwd (io|mac|macswap|flowgen| \
-                     rxonly|txonly|csum|icmpecho|noisy|5tswap) (""|retry)
+                     rxonly|txonly|csum|icmpecho|noisy|5tswap|shared-rxq) (""|retry)
 
 ``retry`` can be specified for forwarding engines except ``rx_only``.
 
@@ -357,6 +357,9 @@ The available information categories are:
 
   L4 swaps the source port and destination port of transport layer (TCP and UDP).
 
+* ``shared-rxq``: Receive only for shared Rx queue.
+  Resolve packet source port from mbuf and update stream statistics accordingly.
+
 Example::
 
    testpmd> set fwd rxonly
-- 
2.33.0