On 08/10/2018 03:49 PM, Jens Freimann wrote:
> This adds a new forwarding mode to testpmd to simulate
> more realistic behavior of a guest machine engaged in receiving
> and sending packets performing Virtual Network Function (VNF).
>
Hi Jens, comments below,
thanks,
Kevin.
> The goal is to enable a simple way of measuring performance impact on
> cache and memory footprint utilization from various VNF co-located on
> the same host machine. For this it does:
>
> * Buffer packets in a FIFO:
>
> Create a fifo to buffer received packets. Once it flows over put
> those packets into the actual tx queue. The fifo is created per tx
> queue and its size can be set with the --buffersize-before-sending
> commandline parameter.
--noisy-tx-sw-buffer-flushtime
>
> A second commandline parameter is used to set a timeout in
> milliseconds after which the fifo is flushed.
>
> --noisy-tx-sw-buffer-size [packet numbers]
> Keep the mbuf in a FIFO and forward the over flooding packets from the
> FIFO. This queue is per TX-queue (after all other packet processing).
>
> --noisy-tx-sw-buffer-flushtime [delay]
> Flush the packet queue if no packets have been seen during
> [delay]. As long as packets are seen, the timer is reset.
>
> Add several options to simulate route lookups (memory reads) in tables
> that can be quite large, as well as route hit statistics update.
> These options simulates the while stack traversal and
> will trash the cache. Memory access is random.
>
> * simulate route lookups:
>
> Allocate a buffer and perform reads and writes on it as specified by
> commandline options:
>
> --noisy-lkup-memory [size]
> Size of the VNF internal memory (MB), in which the random
> read/write will be done, allocated by rte_malloc (hugepages).
>
> --noisy-lkup-num-writes [num]
> Number of random writes in memory per packet should be
> performed, simulating hit-flags update. 64 bits per write,
> all write in different cache lines.
>
> --noisy-lkup-num-reads [num]
> Number of random reads in memory per packet should be
> performed, simulating FIB/table lookups. 64 bits per read,
> all write in different cache lines.
>
> --noisy-lkup-num-reads-writes [num]
> Number of random reads and writes in memory per packet should
> be performed, simulating stats update. 64 bits per read-write, all
> reads and writes in different cache lines.
>
> Signed-off-by: Jens Freimann <jfreim...@redhat.com>
> ---
> app/test-pmd/Makefile | 1 +
> app/test-pmd/meson.build | 1 +
> app/test-pmd/noisy_vnf.c | 269
> ++++++++++++++++++++++++++++
> app/test-pmd/parameters.c | 60 +++++++
> app/test-pmd/testpmd.c | 35 ++++
> app/test-pmd/testpmd.h | 10 ++
> doc/guides/testpmd_app_ug/run_app.rst | 33 ++++
> doc/guides/testpmd_app_ug/testpmd_funcs.rst | 7 +-
> 8 files changed, 414 insertions(+), 2 deletions(-)
> create mode 100644 app/test-pmd/noisy_vnf.c
>
> diff --git a/app/test-pmd/Makefile b/app/test-pmd/Makefile
> index 2b4d604..e2581ca 100644
> --- a/app/test-pmd/Makefile
> +++ b/app/test-pmd/Makefile
> @@ -33,6 +33,7 @@ SRCS-y += rxonly.c
> SRCS-y += txonly.c
> SRCS-y += csumonly.c
> SRCS-y += icmpecho.c
> +SRCS-y += noisy_vnf.c
> SRCS-$(CONFIG_RTE_LIBRTE_IEEE1588) += ieee1588fwd.c
> SRCS-$(CONFIG_RTE_LIBRTE_BPF) += bpf_cmd.c
>
> diff --git a/app/test-pmd/meson.build b/app/test-pmd/meson.build
> index a0b3be0..9ef6ed9 100644
> --- a/app/test-pmd/meson.build
> +++ b/app/test-pmd/meson.build
> @@ -17,6 +17,7 @@ sources = files('cmdline.c',
> 'iofwd.c',
> 'macfwd.c',
> 'macswap.c',
> + 'noisy_vnf.c',
> 'parameters.c',
> 'rxonly.c',
> 'testpmd.c',
> diff --git a/app/test-pmd/noisy_vnf.c b/app/test-pmd/noisy_vnf.c
> new file mode 100644
> index 0000000..dcde7d0
> --- /dev/null
> +++ b/app/test-pmd/noisy_vnf.c
> @@ -0,0 +1,269 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright(c) 2018 Red Hat Corp.
> + */
> +
> +#include <stdarg.h>
> +#include <stdio.h>
> +#include <stdbool.h>
> +#include <string.h>
> +#include <errno.h>
> +#include <stdint.h>
> +#include <unistd.h>
> +#include <inttypes.h>
> +
> +#include <sys/queue.h>
> +#include <sys/stat.h>
> +
> +#include <rte_common.h>
> +#include <rte_log.h>
> +#include <rte_debug.h>
> +#include <rte_cycles.h>
> +#include <rte_memory.h>
> +#include <rte_launch.h>
> +#include <rte_eal.h>
> +#include <rte_per_lcore.h>
> +#include <rte_lcore.h>
> +#include <rte_memcpy.h>
> +#include <rte_mempool.h>
> +#include <rte_mbuf.h>
> +#include <rte_ethdev.h>
> +#include <rte_flow.h>
> +#include <rte_malloc.h>
> +
> +#include "testpmd.h"
> +
> +struct noisy_config {
> + struct rte_ring *f;
> + uint64_t prev_time;
> + char *vnf_mem;
> + bool do_buffering;
> + bool do_flush;
> + bool do_sim;
> +};
> +
> +struct noisy_config *noisy_cfg[RTE_MAX_ETHPORTS];
> +
> +static inline void
> +do_write(char *vnf_mem)
> +{
> + uint64_t i = rte_rand();
> + uint64_t w = rte_rand();
> +
> + vnf_mem[i % ((noisy_lkup_mem_sz * 1024 * 1024) /
> + RTE_CACHE_LINE_SIZE)] = w;
> +}
> +
> +static inline void
> +do_read(char *vnf_mem)
> +{
> + uint64_t i = rte_rand();
> + uint64_t r;
> +
> + r = vnf_mem[i % ((noisy_lkup_mem_sz * 1024 * 1024) /
> + RTE_CACHE_LINE_SIZE)];
> + r++;
> +}
> +
> +static inline void
> +do_readwrite(char *vnf_mem)
> +{
> + do_read(vnf_mem);
> + do_write(vnf_mem);
> +}
> +
> +/*
> + * Simulate route lookups as defined by commandline parameters
> + */
> +static void
> +sim_memory_lookups(struct noisy_config *ncf, uint16_t nb_pkts)
> +{
> + uint16_t i, j;
> +
> + if (!ncf->do_sim)
> + return;
> +
> + for (i = 0; i < nb_pkts; i++) {
> + for (j = 0; j < noisy_lkup_num_writes; j++)
> + do_write(ncf->vnf_mem);
> + for (j = 0; j < noisy_lkup_num_reads; j++)
> + do_read(ncf->vnf_mem);
> + for (j = 0; j < noisy_lkup_num_reads_writes; j++)
> + do_readwrite(ncf->vnf_mem);
> + }
> +}
> +
> +static uint16_t
> +do_retry(uint16_t nb_rx, uint16_t nb_tx, struct rte_mbuf **pkts,
> + struct fwd_stream *fs)
> +{
> + uint32_t retry = 0;
> +
> + while (nb_tx < nb_rx && retry++ < burst_tx_retry_num) {
> + rte_delay_us(burst_tx_delay_time);
> + nb_tx += rte_eth_tx_burst(fs->tx_port, fs->tx_queue,
> + &pkts[nb_tx], nb_rx - nb_tx);
> + }
> +
> + return nb_tx;
> +}
> +
> +static uint32_t
> +dropped_pkts(struct rte_mbuf **pkts, uint16_t nb_rx, uint16_t nb_tx)
> +{
> + if (nb_tx < nb_rx) {
> + do {
> + rte_pktmbuf_free(pkts[nb_tx]);
> + } while (++nb_tx < nb_rx);
> + }
> +
> + return nb_rx - nb_tx;
> +}
> +
> +/*
> + * Forwarding of packets in noisy VNF mode. Forward packets but perform
> + * memory operations first as specified on cmdline.
> + *
> + * Depending on which commandline parameters are specified we have
> + * different cases to handle:
> + *
> + * 1. No FIFO size was given, so we don't do buffering of incoming
> + * packets. This case is pretty much what iofwd does but in this case
> + * we also do simulation of memory accesses (depending on which
> + * parameters were specified for it).
> + * 2. User wants do buffer packets in a FIFO and sent out overflowing
> + * packets.
> + * 3. User wants a FIFO and specifies a time in ms to flush all packets
> + * out of the FIFO
It reads like these are mutually exclusive, whereas I think they can be
combined too. Maybe you can just add a line about combinations or something.
> + */
> +static void
> +pkt_burst_noisy_vnf(struct fwd_stream *fs)
> +{
> + const uint64_t freq_khz = rte_get_timer_hz() / 1000;
> + struct noisy_config *ncf = noisy_cfg[fs->rx_port];
> + struct rte_mbuf *pkts_burst[MAX_PKT_BURST];
> + struct rte_mbuf *tmp_pkts[MAX_PKT_BURST];
> + uint16_t nb_deqd = 0;
> + uint16_t nb_rx = 0;
> + uint16_t nb_tx = 0;
> + uint16_t nb_enqd;
> + unsigned int fifo_free;
> + uint64_t delta_ms;
> + bool needs_flush = false;
> + uint64_t now;
> +
> + nb_rx = rte_eth_rx_burst(fs->rx_port, fs->rx_queue,
> + pkts_burst, nb_pkt_per_burst);
> + if (unlikely(nb_rx == 0))
Perhaps you should jump down to 'if (ncf->do_flush)' to check if it's
time to flush some pkts regardless that you did not receive any new ones?
> + return;
> + fs->rx_packets += nb_rx;
> +
> + if (!ncf->do_buffering) {
> + sim_memory_lookups(ncf, nb_rx);
> + nb_tx = rte_eth_tx_burst(fs->tx_port, fs->tx_queue,
> + pkts_burst, nb_rx);
> + if (unlikely(nb_tx < nb_rx) && fs->retry_enabled)
> + nb_tx += do_retry(nb_rx, nb_tx, pkts_burst, fs);
> + fs->tx_packets += nb_tx;
> + fs->fwd_dropped += dropped_pkts(pkts_burst, nb_rx, nb_tx);
> + return;
> + }
> +
> + fifo_free = rte_ring_free_count(ncf->f);
> + if (fifo_free >= nb_rx) {
> + nb_enqd = rte_ring_enqueue_burst(ncf->f,
> + (void **) pkts_burst, nb_rx, NULL);
> + if (nb_enqd < nb_rx)
> + fs->fwd_dropped += (nb_rx - nb_enqd);
unlikely this would happen, but you'd need to free these pkts
> + sim_memory_lookups(ncf, nb_rx);
> + } else if (fifo_free < nb_rx) {
I don't think the if is needed, the else condition already gaurantees this
> + nb_deqd = rte_ring_dequeue_burst(ncf->f,
> + (void **) tmp_pkts, nb_rx, NULL);
> + nb_enqd = rte_ring_enqueue_burst(ncf->f,
> + (void **) pkts_burst, nb_deqd, NULL);
> + if (nb_deqd > 0) {
> + nb_tx = rte_eth_tx_burst(fs->tx_port,
> + fs->tx_queue, tmp_pkts,
> + nb_deqd);
> + if (unlikely(nb_tx < nb_rx) && fs->retry_enabled)
> + nb_tx += do_retry(nb_rx, nb_tx, tmp_pkts, fs);
> + fs->fwd_dropped += dropped_pkts(tmp_pkts, nb_deqd,
> + nb_tx);
Shouldn't there be sim_memory_lookups() for this path?
> + }
> + }
> +
> + if (ncf->do_flush) {
> + if (!ncf->prev_time)
> + now = ncf->prev_time = rte_get_timer_cycles();
> + else
> + now = rte_get_timer_cycles();
> + delta_ms = (now - ncf->prev_time) / freq_khz;
> + needs_flush = delta_ms >= noisy_tx_sw_buf_flush_time &&
> + noisy_tx_sw_buf_flush_time > 0 && !nb_tx;
> + }
> + while (needs_flush && !rte_ring_empty(ncf->f)) {
> + unsigned int sent;
> + nb_deqd = rte_ring_dequeue_burst(ncf->f, (void **)tmp_pkts,
> + MAX_PKT_BURST, NULL);
> + sent = rte_eth_tx_burst(fs->tx_port, fs->tx_queue,
> + tmp_pkts, nb_deqd);
> + if (unlikely(sent < nb_deqd) && fs->retry_enabled)
> + nb_tx += do_retry(nb_rx, nb_tx, tmp_pkts, fs);
> + fs->fwd_dropped += dropped_pkts(tmp_pkts, nb_deqd, sent);
> + ncf->prev_time = rte_get_timer_cycles();
> + }
> +}
> +
> +#define NOISY_STRSIZE 256
> +#define NOISY_RING "noisy_ring_%d\n"
> +
> +static void
> +noisy_fwd_end(portid_t pi)
> +{
> + rte_free(noisy_cfg[pi]);
this should be freed last
> + rte_ring_free(noisy_cfg[pi]->f);
> + rte_free(noisy_cfg[pi]->vnf_mem);
> +}
> +
> +static void
> +noisy_fwd_begin(portid_t pi)
> +{
> + struct noisy_config *n;
> + char name[NOISY_STRSIZE];
> +
> + noisy_cfg[pi] = rte_zmalloc("testpmd noisy fifo and timers",
> + nb_fwd_ports * sizeof(struct noisy_config),
> + RTE_CACHE_LINE_SIZE);
I don't think 'nb_fwd_ports *' is needed. afaict, you'll just need one
struct per port.
> + if (noisy_cfg == NULL) {
> + rte_exit(EXIT_FAILURE,
> + "rte_zmalloc(%d) struct noisy_config) failed\n",
> + (int) nb_fwd_ports);
> + }
> + n = noisy_cfg[pi];
> + snprintf(name, NOISY_STRSIZE, NOISY_RING, pi);
> + n->f = rte_ring_create(name, noisy_tx_sw_bufsz,
> + rte_socket_id(), 0);
Could be NULL
> + if (noisy_lkup_mem_sz > 0) {
> + n->vnf_mem = (char *) rte_zmalloc("vnf sim memory",
> + noisy_lkup_mem_sz * 1024 * 1024,
> + RTE_CACHE_LINE_SIZE);
> + if (n->vnf_mem == NULL)
> + rte_exit(EXIT_FAILURE,
> + "rte_zmalloc(%" PRIu64 ") for vnf memory)
> failed\n",
> + noisy_lkup_mem_sz);
> + } else if (noisy_lkup_mem_sz == 0 && noisy_tx_sw_bufsz == 0) {
> + rte_exit(EXIT_FAILURE,
> + "--noisy-tx-sw-buffer-size or --noisy-lkup-mem-size
> must be > 0\n");
s/mem-size/memory/
> + }
> + n->do_buffering = noisy_tx_sw_bufsz > 0;
> + n->do_flush = noisy_tx_sw_buf_flush_time > 0;
> + n->do_sim = noisy_lkup_num_writes + noisy_lkup_num_reads +
> + noisy_lkup_num_reads_writes;
> +}
> +
> +struct fwd_engine noisy_vnf_engine = {
> + .fwd_mode_name = "noisy",
> + .port_fwd_begin = noisy_fwd_begin,
> + .port_fwd_end = noisy_fwd_end,
> + .packet_fwd = pkt_burst_noisy_vnf,
> +};
> +
> diff --git a/app/test-pmd/parameters.c b/app/test-pmd/parameters.c
> index 962fad7..85b44af 100644
> --- a/app/test-pmd/parameters.c
> +++ b/app/test-pmd/parameters.c
> @@ -625,6 +625,12 @@
> { "vxlan-gpe-port", 1, 0, 0 },
> { "mlockall", 0, 0, 0 },
> { "no-mlockall", 0, 0, 0 },
> + { "noisy-tx-sw-buffer-size", 1, 0, 0 },
> + { "noisy-tx-sw-buffer-flushtime", 1, 0, 0 },
> + { "noisy-lkup-memory", 1, 0, 0 },
> + { "noisy-lkup-num-writes", 1, 0, 0 },
> + { "noisy-lkup-num-reads", 1, 0, 0 },
> + { "noisy-lkup-num-reads-writes", 1, 0, 0 },
> { 0, 0, 0, 0 },
> };
>
> @@ -1147,6 +1153,60 @@
> do_mlockall = 1;
> if (!strcmp(lgopts[opt_idx].name, "no-mlockall"))
> do_mlockall = 0;
> + if (!strcmp(lgopts[opt_idx].name,
> + "noisy-tx-sw-buffer-size")) {
> + n = atoi(optarg);
> + if (n > 0)
> + noisy_tx_sw_bufsz = n;
> + else
> + rte_exit(EXIT_FAILURE,
> + "noisy-tx-sw-buffer-size must
> be > 0\n");
I commented in v4 about if this/others could be 'n >= 0' to allow for
setting to the default etc. No problem if you prefer not to allow it,
just not sure if comment is missed or not?
> + }
> + if (!strcmp(lgopts[opt_idx].name,
> + "noisy-tx-sw-buffer-flushtime")) {
> + n = atoi(optarg);
> + if (n >= 0)
> + noisy_tx_sw_buf_flush_time = n;
> + else
> + rte_exit(EXIT_FAILURE,
> + "noisy-tx-sw-buffer-flushtime
> must be > 0\n");
log should match '>= 0'
> + }
> + if (!strcmp(lgopts[opt_idx].name,
> + "noisy-lkup-memory")) {
> + n = atoi(optarg);
> + if (n > 0)
> + noisy_lkup_mem_sz = n;
> + else
> + rte_exit(EXIT_FAILURE,
> + "noisy-lkup-memory must be >
> 0\n");
> + }
> + if (!strcmp(lgopts[opt_idx].name,
> + "noisy-lkup-num-writes")) {
> + n = atoi(optarg);
> + if (n > 0)
> + noisy_lkup_num_writes = n;
> + else
> + rte_exit(EXIT_FAILURE,
> + "noisy-lkup-num-writes must be
> > 0\n");
> + }
> + if (!strcmp(lgopts[opt_idx].name,
> + "noisy-lkup-num-reads")) {
> + n = atoi(optarg);
> + if (n > 0)
> + noisy_lkup_num_reads = n;
> + else
> + rte_exit(EXIT_FAILURE,
> + "noisy-lkup-num-reads must be
> > 0\n");
> + }
> + if (!strcmp(lgopts[opt_idx].name,
> + "noisy-lkup-num-reads-writes")) {
> + n = atoi(optarg);
> + if (n > 0)
> + noisy_lkup_num_reads_writes = n;
> + else
> + rte_exit(EXIT_FAILURE,
> + "noisy-lkup-num-reads-writes
> must be > 0\n");
> + }
> break;
> case 'h':
> usage(argv[0]);
> diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c
> index ee48db2..2b1b8c3 100644
> --- a/app/test-pmd/testpmd.c
> +++ b/app/test-pmd/testpmd.c
> @@ -157,6 +157,7 @@ struct fwd_engine * fwd_engines[] = {
> &tx_only_engine,
> &csum_fwd_engine,
> &icmp_echo_engine,
> + &noisy_vnf_engine,
> #if defined RTE_LIBRTE_PMD_SOFTNIC
> &softnic_fwd_engine,
> #endif
> @@ -253,6 +254,40 @@ struct fwd_engine * fwd_engines[] = {
> int16_t tx_rs_thresh = RTE_PMD_PARAM_UNSET;
>
> /*
> + * Configurable value of buffered packets before sending.
> + */
> +uint16_t noisy_tx_sw_bufsz;
> +
> +/*
> + * Configurable value of packet buffer timeout.
> + */
> +uint16_t noisy_tx_sw_buf_flush_time;
> +
> +/*
> + * Configurable value for size of VNF internal memory area
> + * used for simulating noisy neighbour behaviour
> + */
> +uint64_t noisy_lkup_mem_sz;
> +
> +/*
> + * Configurable value of number of random writes done in
> + * VNF simulation memory area.
> + */
> +uint64_t noisy_lkup_num_writes;
> +
> +/*
> + * Configurable value of number of random reads done in
> + * VNF simulation memory area.
> + */
> +uint64_t noisy_lkup_num_reads;
> +
> +/*
> + * Configurable value of number of random reads/wirtes done in
typo
> + * VNF simulation memory area.
> + */
> +uint64_t noisy_lkup_num_reads_writes;
> +
> +/*
> * Receive Side Scaling (RSS) configuration.
> */
> uint64_t rss_hf = ETH_RSS_IP; /* RSS IP by default. */
> diff --git a/app/test-pmd/testpmd.h b/app/test-pmd/testpmd.h
> index a1f66147..796114f 100644
> --- a/app/test-pmd/testpmd.h
> +++ b/app/test-pmd/testpmd.h
> @@ -122,6 +122,8 @@ struct fwd_stream {
> #endif
> };
>
> +
> +
Added whitespace
> /** Descriptor for a single flow. */
> struct port_flow {
> size_t size; /**< Allocated space including data[]. */
> @@ -243,6 +245,7 @@ struct fwd_engine {
> extern struct fwd_engine tx_only_engine;
> extern struct fwd_engine csum_fwd_engine;
> extern struct fwd_engine icmp_echo_engine;
> +extern struct fwd_engine noisy_vnf_engine;
> #ifdef SOFTNIC
> extern struct fwd_engine softnic_fwd_engine;
> #endif
> @@ -375,6 +378,13 @@ struct queue_stats_mappings {
> extern int16_t tx_free_thresh;
> extern int16_t tx_rs_thresh;
>
> +extern uint16_t noisy_tx_sw_bufsz;
> +extern uint16_t noisy_tx_sw_buf_flush_time;
> +extern uint64_t noisy_lkup_mem_sz;
> +extern uint64_t noisy_lkup_num_writes;
> +extern uint64_t noisy_lkup_num_reads;
> +extern uint64_t noisy_lkup_num_reads_writes;
> +
> extern uint8_t dcb_config;
> extern uint8_t dcb_test;
>
> diff --git a/doc/guides/testpmd_app_ug/run_app.rst
> b/doc/guides/testpmd_app_ug/run_app.rst
> index f301c2b..2bf4cf5 100644
> --- a/doc/guides/testpmd_app_ug/run_app.rst
> +++ b/doc/guides/testpmd_app_ug/run_app.rst
> @@ -340,6 +340,7 @@ The commandline options are:
> icmpecho
> ieee1588
> tm
> + noisy
>
> * ``--rss-ip``
>
> @@ -498,3 +499,35 @@ The commandline options are:
> * ``--no-mlockall``
>
> Disable locking all memory.
> +
> +* ``--noisy-tx-sw-buffer-size``
> +
> + Set the number of maximum elements of the FIFO queue to be created
> + for buffering packets. Only available with the noisy forwarding mode.
> + The default value is 0.
> +
> +* ``--noisy-tx-sw-buffer-flushtime``
> +
> + Set the time before packets in the FIFO queue is flushed.
> + Only available with the noisy forwarding mode. The default value is 0.
> +
> +* ``--noisy-lkup-memory=N``
> +
Not sure about the convention of using N. Other descriptions seem to
reference it explicitly.
> + Set the size of the noisy neighbour simulation memory buffer in MB.
> + Only available with the noisy forwarding mode. The default value is 0.
> +
> +
> +* ``--noisy-lkup-num-reads=N``
> +
> + Set the number of reads to be done in noisy neighbour simulation memory
> buffer.
> + Only available with the noisy forwarding mode. The default value is 0.
> +
> +* ``--noisy-lkup-num-writes=N``
> +
> + Set the number of writes to be done in noisy neighbour simulation memory
> buffer.
> + Only available with the noisy forwarding mode. The default value is 0.
> +
> +* ``--noisy-lkup-num-reads-writes=N``
> +
> + Set the number of r/w accesses to be done in noisy neighbour simulation
> memory buffer.
> + Only available with the noisy forwarding mode. The default value is 0.
> diff --git a/doc/guides/testpmd_app_ug/testpmd_funcs.rst
> b/doc/guides/testpmd_app_ug/testpmd_funcs.rst
> index dde205a..e2f9db2 100644
> --- a/doc/guides/testpmd_app_ug/testpmd_funcs.rst
> +++ b/doc/guides/testpmd_app_ug/testpmd_funcs.rst
> @@ -289,7 +289,7 @@ set fwd
> Set the packet forwarding mode::
>
> testpmd> set fwd (io|mac|macswap|flowgen| \
> - rxonly|txonly|csum|icmpecho) (""|retry)
> + rxonly|txonly|csum|icmpecho|noisy) (""|retry)
>
> ``retry`` can be specified for forwarding engines except ``rx_only``.
>
> @@ -323,8 +323,11 @@ The available information categories are:
> * ``softnic``: Demonstrates the softnic forwarding operation. In this mode,
> packet forwarding is
> similar to I/O mode except for the fact that packets are loopback to the
> softnic ports only. Therefore, portmask parameter should be set to softnic
> port only. The various software based custom NIC pipelines specified through
> the softnic firmware (DPDK packet framework script) can be tested in this
> mode. Furthermore, it allows to build 5-level hierarchical QoS scheduler as a
> default option that can be enabled through CLI once testpmd application is
> initialised. The user can modify the default scheduler hierarchy or can
> specify the new QoS Scheduler hierarchy through CLI. Requires
> ``CONFIG_RTE_LIBRTE_PMD_SOFTNIC=y``.
>
> -Example::
> +* ``noisy``: Noisy neighbour simulation.
> + Simulate more realistic behavior of a guest machine engaged in receiving
> + and sending packets performing Virtual Network Function (VNF).
>
> +Example::
> testpmd> set fwd rxonly
>
> Set rxonly packet forwarding mode
>
There's a 'new blank line at EOF warning' here when applying
