Re: [PATCH v6 2/2] Add l2reflect measurement application

[Maxime Coquelin <maxime.coquelin@redhat.com>]

Hi Felix,

On 9/25/22 10:01, Moessbauer, Felix wrote:
>> -----Original Message-----
>> From: Maxime Coquelin <maxime.coquelin@redhat.com>
>> Sent: Tuesday, September 20, 2022 10:02 PM
>> To: Moessbauer, Felix (T CED SES-DE) <felix.moessbauer@siemens.com>;
>> dev@dpdk.org
>> Cc: Schild, Henning (T CED SES-DE) <henning.schild@siemens.com>; Kiszka, Jan
>> (T CED) <jan.kiszka@siemens.com>; thomas@monjalon.net; Marcelo Tosatti
>> <mtosatti@redhat.com>
>> Subject: Re: [PATCH v6 2/2] Add l2reflect measurement application
>>
>> Hi Felix,
>>
>> First, I support the idea of having the l2reflect application part of
>> the DPDK repository.
> 
> Hi Maxime,
> 
> Many thanks for the review.
> I'm currently travelling but plan to address all responses regarding l2reflect in the upcoming week.

Do you still target v22.11 for getting l2reflect in?

Regards,
Maxime

> Best regards,
> Felix
> 
>>
>> Please note CI failed to build it on different platforms:
>> https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fmails.dpd
>> k.org%2Farchives%2Ftest-report%2F2022-
>> September%2F304617.html&amp;data=05%7C01%7Cfelix.moessbauer%40siem
>> ens.com%7Cdd1323af309a42d0a12b08da9b10a598%7C38ae3bcd95794fd4adda
>> b42e1495d55a%7C1%7C0%7C637992793049685048%7CUnknown%7CTWFpbGZ
>> sb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0
>> %3D%7C3000%7C%7C%7C&amp;sdata=eM6SKiinN6Jc%2Fb1lAYpY2TX1x7hxMzA
>> 3iGetLzRzL0g%3D&amp;reserved=0
>>
>> It also fails to build on my Fc35 machine:
>> [3237/3537] Compiling C object app/dpdk-l2reflect.p/l2reflect_main.c.o
>> ../app/l2reflect/main.c: In function 'l2reflect_main_loop':
>> ../app/l2reflect/main.c:560:19: warning: array subscript 'uint64_t {aka
>> long unsigned int}[0]' is partly outside array bounds of 'struct
>> rte_ether_addr[1]' [-Warray-bounds]
>>     560 |         i_win = ((*((uint64_t *)&l2reflect_port_eth_addr)   &
>> MAC_ADDR_CMP) >
>>         |                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> ../app/l2reflect/main.c:110:23: note: while referencing
>> 'l2reflect_port_eth_addr'
>>     110 | struct rte_ether_addr l2reflect_port_eth_addr;
>>         |                       ^~~~~~~~~~~~~~~~~~~~~~~
>> ../app/l2reflect/main.c:561:27: warning: array subscript 'uint64_t {aka
>> long unsigned int}[0]' is partly outside array bounds of 'struct
>> rte_ether_addr[1]' [-Warray-bounds]
>>     561 |                          (*((uint64_t
>> *)&l2reflect_remote_eth_addr) & MAC_ADDR_CMP));
>>         |                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> ../app/l2reflect/main.c:111:23: note: while referencing
>> 'l2reflect_remote_eth_addr'
>>     111 | struct rte_ether_addr l2reflect_remote_eth_addr;
>>         |                       ^~~~~~~~~~~~~~~~~
>>
>> Some more comments inline:
>>
>> On 9/2/22 10:45, Felix Moessbauer wrote:
>>> The l2reflect application implements a ping-pong benchmark to
>>> measure the latency between two instances. For communication,
>>> we use raw ethernet and send one packet at a time. The timing data
>>> is collected locally and min/max/avg values are displayed in a TUI.
>>> Finally, a histogram of the latencies is printed which can be
>>> further processed with the jitterdebugger visualization scripts.
>>> To debug latency spikes, a max threshold can be defined.
>>> If it is hit, a trace point is created on both instances.
>>>
>>> Signed-off-by: Felix Moessbauer <felix.moessbauer@siemens.com>
>>> Signed-off-by: Henning Schild <henning.schild@siemens.com>
>>> ---
>>>    app/l2reflect/colors.c    |   34 ++
>>>    app/l2reflect/colors.h    |   19 +
>>>    app/l2reflect/l2reflect.h |   53 ++
>>>    app/l2reflect/main.c      | 1007 +++++++++++++++++++++++++++++++++++++
>>>    app/l2reflect/meson.build |   21 +
>>>    app/l2reflect/payload.h   |   26 +
>>>    app/l2reflect/stats.c     |  225 +++++++++
>>>    app/l2reflect/stats.h     |   67 +++
>>>    app/l2reflect/utils.c     |   67 +++
>>>    app/l2reflect/utils.h     |   20 +
>>>    app/meson.build           |    1 +
>>>    11 files changed, 1540 insertions(+)
>>>    create mode 100644 app/l2reflect/colors.c
>>>    create mode 100644 app/l2reflect/colors.h
>>>    create mode 100644 app/l2reflect/l2reflect.h
>>>    create mode 100644 app/l2reflect/main.c
>>>    create mode 100644 app/l2reflect/meson.build
>>>    create mode 100644 app/l2reflect/payload.h
>>>    create mode 100644 app/l2reflect/stats.c
>>>    create mode 100644 app/l2reflect/stats.h
>>>    create mode 100644 app/l2reflect/utils.c
>>>    create mode 100644 app/l2reflect/utils.h
>>
>> If we agree to have this application in app/ directory,
>> I think you'll have to add documentation for this new tool in
>> doc/guides/tools/.
>>
>>> diff --git a/app/l2reflect/colors.c b/app/l2reflect/colors.c
>>> new file mode 100644
>>> index 0000000000..af881d8788
>>> --- /dev/null
>>> +++ b/app/l2reflect/colors.c
>>> @@ -0,0 +1,34 @@
>>> +/* SPDX-License-Identifier: BSD-3-Clause
>>> + * Copyright(c) 2020 Siemens AG
>>> + */
>>> +
>>> +#include "colors.h"
>>> +
>>> +const struct color_palette *colors;
>>> +
>>> +static const struct color_palette color_palette_default = {
>>> +	.red = "\x1b[01;31m",
>>> +	.green = "\x1b[01;32m",
>>> +	.yellow = "\x1b[01;33m",
>>> +	.blue = "\x1b[01;34m",
>>> +	.magenta = "\x1b[01;35m",
>>> +	.cyan = "\x1b[01;36m",
>>> +	.reset = "\x1b[0m"
>>> +};
>>> +
>>> +static const struct color_palette color_palette_bw = { .red = "",
>>> +						       .green = "",
>>> +						       .yellow = "",
>>> +						       .blue = "",
>>> +						       .magenta = "",
>>> +						       .cyan = "",
>>> +						       .reset = "" };
>>> +
>>> +void
>>> +enable_colors(int enable)
>>> +{
>>> +	if (enable)
>>> +		colors = &color_palette_default;
>>> +	else
>>> +		colors = &color_palette_bw;
>>> +}
>>> diff --git a/app/l2reflect/colors.h b/app/l2reflect/colors.h
>>> new file mode 100644
>>> index 0000000000..346547138b
>>> --- /dev/null
>>> +++ b/app/l2reflect/colors.h
>>> @@ -0,0 +1,19 @@
>>> +/* SPDX-License-Identifier: BSD-3-Clause
>>> + * Copyright(c) 2020 Siemens AG
>>> + */
>>> +#ifndef _L2REFLECT_COLORS_H_
>>> +#define _L2REFLECT_COLORS_H_
>>> +
>>> +/* posix terminal colors */
>>> +struct color_palette {
>>> +	const char *red, *green, *yellow, *blue, *magenta, *cyan, *reset;
>>> +};
>>> +
>>> +/* ptr to the current tui color palette */
>>> +extern const struct color_palette *colors;
>>> +
>>> +/* disable colored output */
>>> +void
>>> +enable_colors(int enable);
>>> +
>>> +#endif /* _L2REFLECT_COLORS_H_ */
>>> diff --git a/app/l2reflect/l2reflect.h b/app/l2reflect/l2reflect.h
>>> new file mode 100644
>>> index 0000000000..922bd7c281
>>> --- /dev/null
>>> +++ b/app/l2reflect/l2reflect.h
>>> @@ -0,0 +1,53 @@
>>> +/* SPDX-License-Identifier: BSD-3-Clause
>>> + * Copyright(c) 2020 Siemens AG
>>> + */
>>> +
>>> +#include <stdatomic.h>
>>> +
>>> +#ifndef _L2REFLECT_L2REFLECT_H_
>>> +#define _L2REFLECT_L2REFLECT_H_
>>> +
>>> +#define RTE_LOGTYPE_L2REFLECT RTE_LOGTYPE_USER1
>>> +
>>> +/* max size that common 1G NICs support */
>>> +#define MAX_JUMBO_PKT_LEN 9600
>>> +
>>> +/* Used to compare MAC addresses. */
>>> +#define MAC_ADDR_CMP 0xFFFFFFFFFFFFull
>>> +
>>> +#define MAX(x, y) (((x) > (y)) ? (x) : (y))
>>> +#define MIN(x, y) (((x) < (y)) ? (x) : (y))
>>> +
>>> +enum {
>>> +	TRACE_TYPE_DATA,
>>> +	TRACE_TYPE_HELO,
>>> +	TRACE_TYPE_EHLO,
>>> +	TRACE_TYPE_RSET,
>>> +	TRACE_TYPE_QUIT,
>>> +};
>>> +
>>> +enum STATE {
>>> +	/* elect the initial sender */
>>> +	S_ELECT_LEADER = 1,
>>> +	/* reset the counters */
>>> +	S_RESET_TRX = 2,
>>> +	/* measurement S_RUNNING */
>>> +	S_RUNNING = 4,
>>> +	/* terminated by local event */
>>> +	S_LOCAL_TERM = 8,
>>> +	/* terminated by remote event */
>>> +	S_REMOTE_TERM = 16
>>> +};
>>> +
>>> +extern int l2reflect_hist;
>>> +extern unsigned int l2reflect_hist_buckets;
>>> +extern atomic_int l2reflect_output_hist;
>>> +extern int l2reflect_interrupt;
>>> +extern uint64_t l2reflect_sleep_msec;
>>> +extern uint64_t l2reflect_pkt_bytes;
>>> +extern uint16_t l2reflect_port_number;
>>> +extern atomic_int l2reflect_state;
>>> +extern struct rte_ether_addr l2reflect_port_eth_addr;
>>> +extern struct rte_ether_addr l2reflect_remote_eth_addr;
>>> +
>>> +#endif /* _L2REFLECT_L2REFLECT_H_ */
>>> diff --git a/app/l2reflect/main.c b/app/l2reflect/main.c
>>> new file mode 100644
>>> index 0000000000..33a87e8fad
>>> --- /dev/null
>>> +++ b/app/l2reflect/main.c
>>> @@ -0,0 +1,1007 @@
>>> +/* SPDX-License-Identifier: BSD-3-Clause
>>> + * Copyright(c) 2020 Siemens AG
>>> + *
>>> + * The l2reflect application implements a ping-pong benchmark to
>>> + * measure the latency between two instances. For communication,
>>> + * we use raw ethernet and send one packet at a time. The timing data
>>> + * is collected locally and min/max/avg values are displayed in a TUI.
>>> + * Finally, a histogram of the latencies is printed which can be
>>> + * further processed with the jitterdebugger visualization scripts.
>>> + * To debug latency spikes, a max threshold can be defined.
>>> + * If it is hit, a trace point is created on both instances.
>>> + *
>>> + * Examples:
>>> + *   launch (non-rt kernel): l2reflect --lcores 0@0,1@6 -n 1
>>> + *   launch (rt kernel): l2reflect --lcores 0@0,1@6 -n 1 -- -P 50 -r -l
>>> + *
>>> + * For histogram data, launch with -H <usec> -F <output file>, e.g.
>>> + * -H 10 -F histogram.json for a histogram with 10 usec buckets which
>>> + * is written to a histogram.json file. This file can then be visualized
>>> + * using the jitterdebugger plotting scripts:
>>> + *   jitterplot hist histogram.json
>>> + *
>>> + * While the application is running, it can be controlled by sending
>>> + * signals to one of the processes:
>>> + * - SIGUSR1: reset the min/max/avg on both instances
>>> + * - SIGUSR2: output / write the current histogram
>>> + * - SIGHUP/SIGINT: gracefully terminate both instances
>>> + *
>>> + * Note on wiring:
>>> + * The l2reflect application sends the packets via a physical ethernet
>>> + * interface. When running both instances on a single system, at least
>>> + * two dedicated physical ports and a (physical) loopback between them
>>> + * is required.
>>
>> Above text could be used as a basis for the documentation.
>>
>>> + */
>>> +
>>> +#include <stdio.h>
>>> +#include <errno.h>
>>> +#include <stdlib.h>
>>> +#include <string.h>
>>> +#include <stdint.h>
>>> +#include <time.h>
>>> +#include <inttypes.h>
>>> +#include <getopt.h>
>>> +#include <sys/signal.h>
>>> +#include <assert.h>
>>> +#include <unistd.h>
>>> +#ifdef HAS_SYS_IO
>>> +#include <sys/io.h>
>>> +#endif
>>> +#include <sched.h>
>>> +#include <sys/mman.h>
>>> +#include <stdatomic.h>
>>> +
>>> +#include <rte_common.h>
>>> +#include <rte_errno.h>
>>> +#include <rte_log.h>
>>> +#include <rte_memory.h>
>>> +#include <rte_memcpy.h>
>>> +#include <rte_memzone.h>
>>> +#include <rte_eal.h>
>>> +#include <rte_eal_trace.h>
>>> +#include <rte_per_lcore.h>
>>> +#include <rte_launch.h>
>>> +#include <rte_atomic.h>
>>> +#include <rte_cycles.h>
>>> +#include <rte_prefetch.h>
>>> +#include <rte_lcore.h>
>>> +#include <rte_per_lcore.h>
>>> +#include <rte_branch_prediction.h>
>>> +#include <rte_interrupts.h>
>>> +#include <rte_random.h>
>>> +#include <rte_debug.h>
>>> +#include <rte_ether.h>
>>> +#include <rte_ethdev.h>
>>> +#include <rte_ring.h>
>>> +#include <rte_mempool.h>
>>> +#include <rte_mbuf.h>
>>> +
>>> +#include "l2reflect.h"
>>> +#include "payload.h"
>>> +#include "utils.h"
>>> +#include "colors.h"
>>> +#include "stats.h"
>>> +
>>> +#define NSEC_PER_SEC 1000000000
>>> +
>>> +#define NB_MBUF 2047
>>> +
>>> +#define MAX_PKT_BURST 32
>>> +/* warmup a few round before starting the measurement */
>>> +#define WARMUP_ROUNDS 42
>>
>> Would it make sense to have this as default value and provide the user
>> with the possibility to configure it via command line?
>>
>>> +
>>> +/* break after one second */
>>> +#define DEFAULT_BREAKVAL_USEC 1000000ull
>>> +/* break if no rx for more than this rounds */
>>> +#define RX_TIMEOUT_MASK ~0xFFFFFull
>>> +
>>> +/* delay between two election packets */
>>> +#define DELAY_ELECTION_MS 500
>>> +
>>> +int l2reflect_hist;
>>> +unsigned int l2reflect_hist_buckets = HIST_NUM_BUCKETS_DEFAULT;
>>> +atomic_int l2reflect_output_hist;
>>> +int l2reflect_fake_mac;
>>> +int l2reflect_interrupt;
>>> +uint64_t l2reflect_sleep_msec;
>>> +uint64_t l2reflect_pkt_bytes = 64;
>>> +uint16_t l2reflect_port_number;
>>> +atomic_int l2reflect_state;
>>> +struct rte_ether_addr l2reflect_port_eth_addr;
>>> +struct rte_ether_addr l2reflect_remote_eth_addr;
>>> +
>>> +static struct timespec last_sent, last_recv;
>>> +static int quiet, disable_int, priority, policy, l2reflect_mlock;
>>> +
>>> +static atomic_int sleep_start;
>>> +static uint64_t rounds;
>>> +
>>> +/* Configurable number of RX/TX ring descriptors */
>>> +#define RTE_TEST_RX_DESC_DEFAULT 128
>>> +#define RTE_TEST_TX_DESC_DEFAULT 128
>>> +static uint16_t nb_rxd = RTE_TEST_RX_DESC_DEFAULT;
>>> +static uint16_t nb_txd = RTE_TEST_TX_DESC_DEFAULT;
>>> +
>>> +static struct rte_eth_conf port_conf = {
>>> +	.rxmode = {
>>> +		.split_hdr_size = 0,
>>> +	},
>>> +	.txmode = {
>>> +		.mq_mode = RTE_ETH_MQ_TX_NONE,
>>> +	},
>>> +};
>>> +
>>> +static uint32_t l2reflect_q;
>>> +static uint64_t l2reflect_break_usec = DEFAULT_BREAKVAL_USEC;
>>> +
>>> +static struct rte_ether_addr ether_bcast_addr = {
>>> +	.addr_bytes = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }
>>> +};
>>> +
>>> +struct rte_mempool *l2reflect_pktmbuf_pool;
>>> +
>>> +static void
>>> +l2reflect_usage(const char *prgname)
>>> +{
>>> +	printf("%s [EAL options] -- [-p PORT] -P [PRIO] [-b USEC] [-n SIZE] [-r] [-
>> f] [-l]"
>>> +	       "[-q] [-d] [-H USEC] [-B NUM] [-F FILE] [-S] [-i MSEC] [-m] [-c] [-
>> h]\n"
>>> +	       "  -p PORT: port to configure\n"
>>> +	       "  -P PRIO: scheduling priority to use\n"
>>> +	       "  -b USEC: break when latency > USEC\n"
>>> +	       "  -n SIZE: size of packet in bytes [%i,%i]\n"
>>> +	       "           (when using jumbo frames, sender and receiver values have
>> to match)\n"
>>> +	       "  -r: scheduling policy SCHED_RR\n"
>>> +	       "  -f: scheduling policy SCHED_FIFO\n"
>>> +	       "  -l: lock memory (mlockall)\n"
>>> +	       "  -q: quiet, do not print stats\n"
>>> +#ifdef HAS_SYS_IO
>>> +	       "  -d: ignore maskable interrupts\n"
>>> +#endif
>>> +	       "  -H USEC: create histogram of latencies with USEC time slices\n"
>>> +	       "  -B NUM: number of histogram buckets\n"
>>> +	       "  -F FILE: write histogram to file\n"
>>> +	       "  -S: start processing threads in sleep, wake with SIGCONT\n"
>>> +	       "  -i MSEC: use interrupts instead of polling (cont. on interrupt or
>> after MSEC)\n"
>>> +	       "  -m: fake the source mac addr by adding 1 to the last tuple\n"
>>> +	       "  -c: disable colored output\n"
>>> +	       "  -h: display help message\n",
>>> +	       prgname, RTE_ETHER_MIN_LEN, MAX_JUMBO_PKT_LEN);
>>> +}
>>> +
>>> +static int
>>> +check_opts_for_help(int argc, char **argv, void(*display_help)(const char *))
>>> +{
>>> +	if (argc > 2 && !strncmp(argv[1], "--", 3)) {
>>> +		if (!strncmp(argv[2], "-h", 3) || !strncmp(argv[2], "--help", 7)) {
>>> +			display_help(argv[0]);
>>> +			return 1;
>>> +		}
>>> +	}
>>> +	return 0;
>>> +}
>>> +
>>> +/* Parse the argument given in the command line of the application */
>>> +static int
>>> +l2reflect_parse_args(int argc, char **argv)
>>> +{
>>> +	int opt, ret;
>>> +	char **argvopt;
>>> +	int option_index;
>>> +	int opt_colors = 1;
>>> +	char *prgname = argv[0];
>>> +	static struct option lgopts[] = { { NULL, 0, 0, 0 } };
>>> +
>>> +	argvopt = argv;
>>> +	policy = SCHED_OTHER;
>>> +	hist_filename = NULL;
>>> +	l2reflect_output_hist = 0;
>>> +
>>> +	while ((opt = getopt_long(argc, argvopt, "p:P:b:H:B:F:i:n:qdrflScm",
>> lgopts,
>>> +				  &option_index)) != EOF) {
>>> +		switch (opt) {
>>> +		/* port */
>>> +		case 'p':
>>> +			l2reflect_port_number =
>>> +				(uint16_t)strtoul(optarg, NULL, 10);
>>> +			break;
>>> +		case 'P':
>>> +			priority = strtoul(optarg, NULL, 10);
>>> +			if (priority > 0) {
>>> +				if (policy == SCHED_OTHER)
>>> +					policy = SCHED_RR;
>>> +				l2reflect_mlock = 1;
>>> +			}
>>> +			break;
>>> +		case 'b':
>>> +			l2reflect_break_usec = strtoul(optarg, NULL, 10);
>>> +			break;
>>> +		case 'S':
>>> +			sleep_start = 1;
>>> +			break;
>>> +		case 'q':
>>> +			quiet = 1;
>>> +			break;
>>> +		case 'd':
>>> +			disable_int = 1;
>>> +			break;
>>> +		case 'r':
>>> +			policy = SCHED_RR;
>>> +			break;
>>> +		case 'f':
>>> +			policy = SCHED_FIFO;
>>> +			break;
>>> +		case 'l':
>>> +			l2reflect_mlock = 1;
>>> +			break;
>>> +		case 'H':
>>> +			l2reflect_hist = 1;
>>> +			hist_bucket_usec = strtoul(optarg, NULL, 10);
>>> +#ifndef RTE_HAS_JANSSON
>>> +			printf("not compiled with cjson support\n");
>>
>> s/cjson/jansson/
>>
>>> +			return -1;
>>> +#endif
>>> +			break;
>>> +		case 'B':
>>> +			l2reflect_hist_buckets = strtoul(optarg, NULL, 10);
>>> +			break;
>>> +		case 'F':
>>> +			hist_filename = strndup(optarg, 128);
>>> +			break;
>>> +		case 'i':
>>> +			l2reflect_interrupt = 1;
>>> +			l2reflect_sleep_msec = strtoul(optarg, NULL, 10);
>>> +			break;
>>> +		case 'n':
>>> +			l2reflect_pkt_bytes = strtoull(optarg, NULL, 10);
>>> +			if (l2reflect_pkt_bytes < RTE_ETHER_MIN_LEN ||
>>> +			   l2reflect_pkt_bytes > MAX_JUMBO_PKT_LEN) {
>>> +				printf("packet size %" PRIu64 " not valid\n",
>> l2reflect_pkt_bytes);
>>> +				return -1;
>>> +			}
>>> +			if (l2reflect_pkt_bytes >
>> RTE_MBUF_DEFAULT_DATAROOM) {
>>> +				printf("NOT IMPLEMENTED. Packet size %"
>> PRIu64 " requires segmented buffers.\n",
>>> +					l2reflect_pkt_bytes);
>>> +				return -1;
>>> +			}
>>> +			break;
>>> +		case 'c':
>>> +			opt_colors = 0;
>>> +			break;
>>> +		case 'm':
>>> +			l2reflect_fake_mac = 1;
>>> +			break;
>>> +		default:
>>> +			l2reflect_usage(prgname);
>>> +			return -1;
>>> +		}
>>> +	}
>>> +
>>> +	if (optind >= 0)
>>> +		argv[optind - 1] = prgname;
>>> +
>>> +	if (hist_filename && !l2reflect_hist) {
>>> +		printf("-F switch requires -H switch as well\n");
>>> +		return -1;
>>> +	}
>>> +
>>> +	/* output is redirected, disable coloring */
>>> +	if (!isatty(fileno(stdout)))
>>> +		opt_colors = 0;
>>> +
>>> +	enable_colors(opt_colors);
>>> +
>>> +	ret = optind - 1;
>>> +	optind = 0; /* reset getopt lib */
>>> +	return ret;
>>> +}
>>> +
>>> +/* Send a burst of one packet */
>>> +static inline int
>>> +l2reflect_send_packet(struct rte_mbuf **m, uint16_t port)
>>> +{
>>> +	unsigned int ret;
>>> +	struct rte_ether_hdr *eth;
>>> +	struct my_magic_packet *pkt;
>>> +	uint16_t type;
>>> +
>>> +	eth = rte_pktmbuf_mtod(*m, struct rte_ether_hdr *);
>>> +	pkt = (struct my_magic_packet *)eth;
>>> +	type = pkt->type;
>>> +
>>> +	if (likely(type == TRACE_TYPE_DATA))
>>> +		clock_gettime(CLOCK_MONOTONIC, &last_sent);
>>> +	ret = rte_eth_tx_burst(port, l2reflect_q, m, 1);
>>> +	if (unlikely(ret < 1))
>>> +		rte_pktmbuf_free(*m);
>>> +	return 0;
>>> +}
>>> +
>>> +static inline void
>>> +l2reflect_simple_forward(struct rte_mbuf *m)
>>> +{
>>> +	struct rte_ether_hdr *eth;
>>> +	struct my_magic_packet *pkt;
>>> +
>>> +	eth = rte_pktmbuf_mtod(m, struct rte_ether_hdr *);
>>> +	pkt = (struct my_magic_packet *)eth;
>>> +
>>> +	/* dst addr */
>>> +	rte_ether_addr_copy(&eth->src_addr, &eth->dst_addr);
>>> +	/* src addr */
>>> +	rte_ether_addr_copy(&l2reflect_port_eth_addr, &eth->src_addr);
>>> +
>>> +	if (unlikely(pkt->magic == MAGIC_TRACE_PAYLOAD))
>>> +		rte_eal_trace_generic_str("sending traced packet");
>>> +
>>> +	l2reflect_send_packet(&m, l2reflect_port_number);
>>> +}
>>> +
>>> +static struct rte_mbuf *
>>> +l2reflect_new_pkt(unsigned int type)
>>> +{
>>> +	struct rte_mbuf *m;
>>> +	struct rte_ether_hdr *eth;
>>> +	struct my_magic_packet *pkt;
>>> +	uint64_t frame_bytes = RTE_ETHER_MIN_LEN;
>>> +
>>> +	m = rte_pktmbuf_alloc(l2reflect_pktmbuf_pool);
>>> +	if (m == NULL)
>>> +		rte_exit(EXIT_FAILURE, "rte_pktmbuf_alloc failed\n");
>>> +
>>> +	eth = rte_pktmbuf_mtod(m, struct rte_ether_hdr *);
>>> +
>>> +	if (type == TRACE_TYPE_DATA)
>>> +		frame_bytes = l2reflect_pkt_bytes;
>>> +
>>> +	/* zero out packet to make dumps better readable */
>>> +	memset(eth, 0, frame_bytes - RTE_ETHER_CRC_LEN);
>>> +
>>> +	if (type == TRACE_TYPE_HELO)
>>> +		rte_ether_addr_copy(&ether_bcast_addr, &eth->dst_addr);
>>> +	else
>>> +		rte_ether_addr_copy(&l2reflect_remote_eth_addr, &eth-
>>> dst_addr);
>>> +
>>> +	/* src addr */
>>> +	rte_ether_addr_copy(&l2reflect_port_eth_addr, &eth->src_addr);
>>> +	eth->ether_type = rte_cpu_to_be_16(ETHER_TYPE_L2REFLECT);
>>> +
>>> +	m->data_len = frame_bytes - RTE_ETHER_CRC_LEN;
>>> +	m->pkt_len = frame_bytes - RTE_ETHER_CRC_LEN;
>>> +
>>> +	pkt = (struct my_magic_packet *)eth;
>>> +	pkt->type = type;
>>> +	pkt->breakval = l2reflect_break_usec;
>>> +	pkt->req_pkt_bytes = l2reflect_pkt_bytes;
>>> +
>>> +	return m;
>>> +}
>>> +
>>> +static void
>>> +l2reflect_send_reset(void)
>>> +{
>>> +	struct rte_mbuf *m;
>>> +	m = l2reflect_new_pkt(TRACE_TYPE_RSET);
>>> +	l2reflect_send_packet(&m, l2reflect_port_number);
>>> +}
>>> +
>>> +static void
>>> +l2reflect_send_quit(void)
>>> +{
>>> +	struct rte_mbuf *m;
>>> +	m = l2reflect_new_pkt(TRACE_TYPE_QUIT);
>>> +	l2reflect_send_packet(&m, l2reflect_port_number);
>>> +}
>>> +
>>> +static void
>>> +l2reflect_new_ball(void)
>>> +{
>>> +	struct rte_mbuf *pnewball;
>>> +	struct rte_ether_hdr *eth;
>>> +	struct my_magic_packet *pkt;
>>> +	char mac_src_str[RTE_ETHER_ADDR_FMT_SIZE];
>>> +	char mac_dst_str[RTE_ETHER_ADDR_FMT_SIZE];
>>> +
>>> +	RTE_LOG(INFO, L2REFLECT, "Should create a packet to play with ...\n");
>>> +	pnewball = l2reflect_new_pkt(TRACE_TYPE_DATA);
>>> +
>>> +	eth = rte_pktmbuf_mtod(pnewball, struct rte_ether_hdr *);
>>> +
>>> +	rte_ether_format_addr(mac_src_str, sizeof(mac_src_str),
>> &l2reflect_port_eth_addr);
>>> +	rte_ether_format_addr(mac_dst_str, sizeof(mac_dst_str),
>> &l2reflect_remote_eth_addr);
>>> +	RTE_LOG(INFO, L2REFLECT, "from MAC address: %s to %s\n\n",
>> mac_src_str, mac_dst_str);
>>> +
>>> +	pkt = (struct my_magic_packet *)eth;
>>> +
>>> +	/* we are tracing lets tell the others */
>>> +	if (l2reflect_break_usec)
>>> +		pkt->magic = MAGIC_TRACE_PAYLOAD;
>>> +
>>> +	l2reflect_send_packet(&pnewball, l2reflect_port_number);
>>> +}
>>> +
>>> +static inline int64_t
>>> +calcdiff_ns(struct timespec t1, struct timespec t2)
>>> +{
>>> +	int64_t diff;
>>> +	diff = NSEC_PER_SEC * (int64_t)((int)t1.tv_sec - (int)t2.tv_sec);
>>> +	diff += ((int)t1.tv_nsec - (int)t2.tv_nsec);
>>> +	return diff;
>>> +}
>>> +
>>> +/* filter the received packets for actual l2reflect messages */
>>> +static inline unsigned int
>>> +l2reflect_rx_filter(
>>> +	struct rte_mbuf *buf)
>>> +{
>>> +	struct rte_ether_hdr *eth;
>>> +	eth = rte_pktmbuf_mtod(buf, struct rte_ether_hdr *);
>>> +
>>> +	if (unlikely(buf->nb_segs > 1))
>>> +		RTE_LOG(WARNING, L2REFLECT, "Segmented packet: data-len:
>> %i, pkt-len: %i, #seg: %i\n",
>>> +			buf->data_len, buf->pkt_len, buf->nb_segs);
>>> +
>>> +	/* check for the l2reflect ether type */
>>> +	if (unlikely(eth->ether_type !=
>> rte_cpu_to_be_16(ETHER_TYPE_L2REFLECT)))
>>> +		return 0;
>>> +
>>> +	/*
>>> +	 * if the packet is not from our partner
>>> +	 * (and we already have a partner), drop it
>>> +	 */
>>> +	if (unlikely(l2reflect_state != S_ELECT_LEADER &&
>>> +		!rte_is_same_ether_addr(&eth->src_addr,
>> &l2reflect_remote_eth_addr)))
>>> +		return 0;
>>> +
>>> +	/* filter bounce-back packets */
>>> +	if (unlikely(rte_is_same_ether_addr(&eth->src_addr,
>> &l2reflect_port_eth_addr)))
>>> +		return 0;
>>> +
>>> +	return 1;
>>> +}
>>> +
>>> +/*
>>> + * automatically elect the leader of the benchmark by
>>> + * sending out HELO packets and waiting for responses.
>>> + * On response, the mac addresses are compared and the
>>> + * numerically larger one becomes the leader.
>>> + */
>>> +static int
>>> +elect_leader(uint16_t portid)
>>> +{
>>> +	struct rte_mbuf *pkts_burst[MAX_PKT_BURST];
>>> +	struct rte_mbuf *m;
>>> +	struct rte_ether_hdr *eth;
>>> +	struct rte_ether_addr *src_addr;
>>> +	struct rte_eth_dev_info dev_info;
>>> +	struct my_magic_packet *pkt;
>>> +	unsigned int i, nb_rx;
>>> +	int ehlo_send = 0;
>>> +	int i_win;
>>> +
>>> +	while (l2reflect_state == S_ELECT_LEADER) {
>>> +		/* send a packet to make sure the MAC addr of this interface is
>> publicly known */
>>> +		m = l2reflect_new_pkt(TRACE_TYPE_HELO);
>>> +		RTE_LOG(INFO, L2REFLECT, "looking for player HELO\n");
>>> +		l2reflect_send_packet(&m, l2reflect_port_number);
>>> +		rte_delay_ms(DELAY_ELECTION_MS);
>>> +
>>> +		/* receive election packets */
>>> +		nb_rx = rte_eth_rx_burst(portid, l2reflect_q, pkts_burst,
>>> +					 MAX_PKT_BURST);
>>> +
>>> +		/* note: do not short-circuit as otherwise the mbufs are not
>> freed */
>>> +		for (i = 0; i < nb_rx; i++) {
>>> +			m = pkts_burst[i];
>>> +			eth = rte_pktmbuf_mtod(m, struct rte_ether_hdr *);
>>> +			src_addr = &eth->src_addr;
>>> +			pkt = (struct my_magic_packet *)eth;
>>> +
>>> +			if (!l2reflect_rx_filter(m)) {
>>> +				rte_pktmbuf_free(m);
>>> +				continue;
>>> +			}
>>> +
>>> +			if (pkt->type == TRACE_TYPE_EHLO && l2reflect_state
>> == S_ELECT_LEADER) {
>>> +				/* check if both modes are equal */
>>> +				if (((l2reflect_pkt_bytes <= RTE_ETHER_MTU)
>>> +				   != (pkt->req_pkt_bytes <=
>> RTE_ETHER_MTU))) {
>>> +					l2reflect_state = S_LOCAL_TERM;
>>> +					m =
>> l2reflect_new_pkt(TRACE_TYPE_QUIT);
>>> +					l2reflect_send_packet(&m,
>> l2reflect_port_number);
>>> +					rte_exit(EXIT_FAILURE,
>>> +						"remote and local jumbo
>> config does not match "
>>> +						"(%" PRIu64 " vs %" PRIu64
>> ")\n",
>>> +						l2reflect_pkt_bytes, pkt-
>>> req_pkt_bytes);
>>> +				}
>>> +				if (l2reflect_pkt_bytes != pkt->req_pkt_bytes) {
>>> +					l2reflect_pkt_bytes =
>> MAX(l2reflect_pkt_bytes,
>>> +								  pkt-
>>> req_pkt_bytes);
>>> +
>> 	rte_eth_dev_info_get(l2reflect_port_number, &dev_info);
>>> +					const uint32_t overhead_len =
>> eth_dev_get_overhead_len(
>>> +
>> 	dev_info.max_rx_pktlen,
>>> +
>> 	dev_info.max_mtu);
>>> +					const uint16_t mtu =
>> MAX(l2reflect_pkt_bytes - overhead_len,
>>> +
>> dev_info.min_mtu);
>>> +					RTE_LOG(INFO, L2REFLECT,
>>> +						"update frame sizes: frame: %"
>> PRIu64 ", MTU %d\n",
>>> +						l2reflect_pkt_bytes, mtu);
>>> +					const int ret = rte_eth_dev_set_mtu(
>>> +
>> 	l2reflect_port_number,
>>> +								mtu);
>>> +					if (ret < 0)
>>> +						rte_exit(EXIT_FAILURE, "failed
>> to update MTU: %s\n",
>>> +								 strerror(-ret));
>>> +				}
>>> +
>>> +				if (ehlo_send) {
>>> +					l2reflect_state = S_RUNNING;
>>> +					RTE_LOG(INFO, L2REFLECT, "Enter
>> running state\n");
>>> +				}
>>> +			}
>>> +			/* we got a HELO packet, respond with EHLO */
>>> +			if (pkt->type == TRACE_TYPE_HELO) {
>>> +				char
>> mac_str_other[RTE_ETHER_ADDR_FMT_SIZE];
>>> +				rte_ether_addr_copy(src_addr,
>> &l2reflect_remote_eth_addr);
>>> +				m = l2reflect_new_pkt(TRACE_TYPE_EHLO);
>>> +				rte_ether_format_addr(
>>> +				  mac_str_other, sizeof(mac_str_other),
>> &l2reflect_remote_eth_addr);
>>> +				RTE_LOG(INFO, L2REFLECT, "found one HELO
>> from %s\n", mac_str_other);
>>> +				l2reflect_send_packet(&m,
>> l2reflect_port_number);
>>> +				ehlo_send = 1;
>>> +			}
>>> +			rte_pktmbuf_free(m);
>>
>> The loop content could be moved in a dedicated function, it would
>> improve the readability.
>>
>>> +		}
>>> +	}
>>> +
>>> +	if (rte_is_same_ether_addr(&l2reflect_port_eth_addr,
>> &l2reflect_remote_eth_addr))
>>> +		rte_exit(EXIT_FAILURE, "talking to myself ... confused\n");
>>> +
>>> +	/* the one with the bigger MAC is the leader */
>>> +	i_win = ((*((uint64_t *)&l2reflect_port_eth_addr)   & MAC_ADDR_CMP)
>>>
>>> +			 (*((uint64_t *)&l2reflect_remote_eth_addr) &
>> MAC_ADDR_CMP));
>>> +
>>> +	RTE_LOG(INFO, L2REFLECT, "i am the \"%s\"\n", i_win ? "rick" :
>> "morty");
>>> +
>>> +	return i_win;
>>> +}
>>> +
>>> +/*
>>> + * add the measured time diff to the statistics.
>>> + * return false if threshold is hit
>>> + */
>>> +static inline int
>>> +add_to_record(const uint64_t diff)
>>> +{
>>> +	record.rounds++;
>>> +	/* do not count the first rounds, diff would be too high */
>>> +	if (record.rounds < WARMUP_ROUNDS)
>>> +		return 1;
>>> +
>>> +	if (l2reflect_hist) {
>>> +		const uint64_t bucket =
>>> +			MIN(diff / (hist_bucket_usec * 1000),
>> l2reflect_hist_buckets-1);
>>> +		record.hist[bucket]++;
>>> +	}
>>> +
>>> +	record.avg_round_ns += (double)diff;
>>> +	if (diff < record.min_round_ns)
>>> +		record.min_round_ns = diff;
>>> +	if (diff > record.max_round_ns) {
>>> +		record.max_round_ns = diff;
>>> +		if (l2reflect_break_usec &&
>>> +		   (record.max_round_ns > (l2reflect_break_usec * 1000)))
>>> +			return 0;
>>> +	}
>>> +	return 1;
>>> +}
>>> +
>>> +/*
>>> + * process a single packet.
>>> + * return false if latency threshold is hit
>>> + */
>>> +static inline int
>>> +process_packet(
>>> +	struct my_magic_packet *pkt,
>>> +	struct timespec *rx_time,
>>> +	uint64_t *diff)
>>> +{
>>> +	if (pkt->type == TRACE_TYPE_DATA) {
>>> +		rte_memcpy(&last_recv, rx_time, sizeof(*rx_time));
>>> +		*diff = calcdiff_ns(last_recv, last_sent);
>>> +		if (!unlikely(add_to_record(*diff))) {
>>> +			/* TODO: improve tracing */
>>> +			rte_eal_trace_generic_u64(record.max_round_ns /
>> 1000);
>>> +			return 0;
>>> +		}
>>> +	}
>>> +	if (pkt->magic == MAGIC_TRACE_PAYLOAD)
>>> +		rte_eal_trace_generic_str("received traced packet");
>>> +
>>> +	return 1;
>>> +}
>>> +
>>> +/*
>>> + * free all packet buffers in the range [begin, end[.
>>> + */
>>> +static void
>>> +free_pktbufs(
>>> +		struct rte_mbuf **bufs,
>>> +		int begin,
>>> +		int end)
>>> +{
>>> +	int i = begin;
>>> +	for (; i < end; i++)
>>> +		rte_pktmbuf_free(bufs[0]);
>>
>> rte_pktmbuf_free(bufs[i]) ?
>>
>>> +}
>>> +
>>> +/*
>>> + * return 1 in case the ball was lost (cheap check)
>>> + */
>>> +static inline void
>>> +check_ball_lost(const uint64_t dp_idle) {
>>> +	/* only check if we are in running state and have a breakval */
>>> +	if (unlikely(dp_idle & RX_TIMEOUT_MASK) &&
>>> +	   l2reflect_state == S_RUNNING &&
>>> +	   l2reflect_break_usec &&
>>> +	   record.rounds > WARMUP_ROUNDS) {
>>> +		RTE_LOG(INFO, L2REFLECT, "lost ball after %" PRIu64 "
>> rounds\n", record.rounds);
>>> +		l2reflect_state = S_LOCAL_TERM;
>>> +	}
>>> +}
>>> +
>>> +/* main processing loop */
>>> +static void
>>> +l2reflect_main_loop(void)
>>> +{
>>> +	struct rte_mbuf *pkts_burst[MAX_PKT_BURST];
>>> +	struct rte_mbuf *m;
>>> +	unsigned int lcore_id;
>>> +	unsigned int j, nb_rx, nb_evt;
>>> +	uint16_t portid;
>>> +	/* number of consequent idle passes */
>>> +	uint64_t dp_idle = 0;
>>> +	uint64_t diff = 0;
>>> +	int sender;
>>> +	struct my_magic_packet *pkt;
>>> +	struct rte_ether_hdr *eth;
>>> +	struct rte_epoll_event event;
>>> +
>>> +	lcore_id = rte_lcore_id();
>>> +
>>> +	RTE_LOG(INFO, L2REFLECT, "entering main loop on lcore %u\n",
>> lcore_id);
>>> +
>>> +	portid = l2reflect_port_number;
>>> +	RTE_LOG(INFO, L2REFLECT, " -- lcoreid=%u portid=%u\n", lcore_id,
>>> +		portid);
>>> +	assert_link_status(portid);
>>> +
>>> +restart:
>>> +	init_record();
>>> +	rte_eth_stats_reset(portid);
>>> +	l2reflect_state = S_ELECT_LEADER;
>>> +	sender = elect_leader(portid);
>>> +
>>> +	if (l2reflect_break_usec)
>>> +		rte_eal_trace_generic_str("hit breakval");
>>> +
>>> +	/* the leader election implements a latch (half-barrier).
>>> +	 * To ensure that the other party is in running state, we
>>> +	 * have to wait at least a full election period
>>> +	 */
>>> +	rte_delay_ms(DELAY_ELECTION_MS * 2);
>>> +
>>> +	/* we are the sender so we bring one ball into the game */
>>> +	if (sender)
>>> +		l2reflect_new_ball();
>>> +
>>> +	/* reset the record */
>>> +	init_record();
>>> +	while (l2reflect_state == S_RUNNING) {
>>> +		struct timespec rx_time;
>>> +
>>> +		if (l2reflect_interrupt) {
>>> +			rte_eth_dev_rx_intr_enable(portid, l2reflect_q);
>>> +			/* wait for interrupt or timeout */
>>> +			nb_evt = rte_epoll_wait(RTE_EPOLL_PER_THREAD,
>> &event, 1,
>>> +						l2reflect_sleep_msec);
>>> +			rte_eth_dev_rx_intr_disable(portid, l2reflect_q);
>>> +			if (nb_evt == 0 && rounds > WARMUP_ROUNDS)
>>> +				++record.timeouts;
>>> +		}
>>> +
>>> +		nb_rx = rte_eth_rx_burst(portid, l2reflect_q, pkts_burst,
>>> +					 MAX_PKT_BURST);
>>> +
>>> +		if (nb_rx) {
>>> +			clock_gettime(CLOCK_MONOTONIC, &rx_time);
>>> +			dp_idle = 0;
>>> +		} else
>>> +			++dp_idle;
>>> +
>>> +		for (j = 0; j < nb_rx; j++) {
>>> +			m = pkts_burst[j];
>>> +			eth = rte_pktmbuf_mtod(m, struct rte_ether_hdr *);
>>> +			pkt = (struct my_magic_packet *)eth;
>>> +
>>> +			rte_prefetch0(eth);
>>> +
>>> +			if (unlikely(!l2reflect_rx_filter(m))) {
>>> +				rte_pktmbuf_free(m);
>>> +				continue;
>>> +			}
>>> +
>>> +			/* remote is telling us to reset or stop */
>>> +			if (unlikely(pkt->type == TRACE_TYPE_RSET)) {
>>> +				free_pktbufs(pkts_burst, j, nb_rx);
>>> +				goto restart;
>>> +			}
>>> +			if (unlikely(pkt->type == TRACE_TYPE_QUIT)) {
>>> +				l2reflect_state = S_REMOTE_TERM;
>>> +				free_pktbufs(pkts_burst, j, nb_rx);
>>> +				break;
>>> +			}
>>> +
>>> +			if (likely(l2reflect_state == S_RUNNING)) {
>>> +				if (unlikely(!process_packet(pkt, &rx_time,
>> &diff))) {
>>> +					l2reflect_state = S_LOCAL_TERM;
>>> +					free_pktbufs(pkts_burst, j, nb_rx);
>>> +					break;
>>> +				}
>>> +				l2reflect_simple_forward(m);
>>> +			}
>>> +		}
>>> +		check_ball_lost(dp_idle);
>>> +	}
>>> +
>>> +	const int state_cpy = l2reflect_state;
>>> +	switch (state_cpy) {
>>> +	case S_RESET_TRX:
>>> +		l2reflect_send_reset();
>>> +		l2reflect_state = S_ELECT_LEADER;
>>> +		/* fallthrough */
>>> +	case S_ELECT_LEADER:
>>> +		goto restart;
>>> +	}
>>> +
>>> +	if (state_cpy == S_LOCAL_TERM) {
>>> +		rte_eal_trace_generic_str("local termination");
>>> +		l2reflect_send_quit();
>>> +	} else if (state_cpy == S_REMOTE_TERM) {
>>> +		RTE_LOG(INFO, L2REFLECT, "received message that remote hit
>> threshold (or is cancelled)\n");
>>> +	}
>>> +}
>>> +
>>> +static int
>>> +l2reflect_launch_one_lcore(__rte_unused void *dummy)
>>> +{
>>> +	struct sched_param param;
>>> +	int err;
>>> +
>>> +	if (sleep_start) {
>>> +		RTE_LOG(INFO, L2REFLECT, "Sleeping and waiting for
>> SIGCONT\n");
>>> +		while (sleep_start) {
>>> +			rte_delay_ms(10);
>>> +			if (l2reflect_state == S_LOCAL_TERM)
>>> +				rte_exit(EXIT_SUCCESS, "Quit\n");
>>> +		}
>>> +		RTE_LOG(INFO, L2REFLECT, "Got SIGCONT, continuing");
>>> +	}
>>> +	if (l2reflect_mlock) {
>>> +		err = mlockall(MCL_CURRENT | MCL_FUTURE);
>>> +		if (err)
>>> +			rte_exit(EXIT_FAILURE, "mlockall failed: %s\n",
>>> +				 strerror(errno));
>>> +	}
>>> +	if (priority > 0 || policy != SCHED_OTHER) {
>>> +		memset(&param, 0, sizeof(param));
>>> +		param.sched_priority = priority;
>>> +		err = sched_setscheduler(0, policy, &param);
>>> +		if (err)
>>> +			rte_exit(EXIT_FAILURE,
>>> +				 "sched_setscheduler failed: %s\n",
>>> +				 strerror(errno));
>>> +	}
>>> +	if (l2reflect_interrupt) {
>>> +		err = rte_eth_dev_rx_intr_ctl_q(l2reflect_port_number,
>>> +						l2reflect_q,
>>> +						RTE_EPOLL_PER_THREAD,
>>> +						RTE_INTR_EVENT_ADD,
>> NULL);
>>> +		if (err)
>>> +			rte_exit(EXIT_FAILURE,
>>> +				 "could not register I/O interrupt\n");
>>> +	}
>>> +	l2reflect_main_loop();
>>> +	return 0;
>>> +}
>>> +
>>> +static void
>>> +sig_handler(int signum)
>>> +{
>>> +	switch (signum) {
>>> +	case SIGUSR1:
>>> +		if (l2reflect_state == S_RUNNING)
>>> +			l2reflect_state = S_RESET_TRX;
>>> +		break;
>>> +	case SIGUSR2:
>>> +		l2reflect_output_hist = 1;
>>> +		break;
>>> +	case SIGCONT:
>>> +		sleep_start = 0;
>>> +		break;
>>> +	case SIGHUP:
>>> +	case SIGINT:
>>> +		l2reflect_state = S_LOCAL_TERM;
>>> +		break;
>>> +	}
>>> +}
>>> +
>>> +int
>>> +main(int argc, char **argv)
>>> +{
>>> +	struct rte_eth_dev_info dev_info;
>>> +	struct rte_eth_txconf txconf;
>>> +	int ret;
>>> +	uint32_t i;
>>> +	uint16_t nb_ports;
>>> +	unsigned int lcore_id;
>>> +	struct sigaction action;
>>> +	bzero(&action, sizeof(action));
>>> +	char mempool_name[128];
>>> +	char mac_str[RTE_ETHER_ADDR_FMT_SIZE];
>>> +
>>> +	action.sa_handler = sig_handler;
>>> +	if (sigaction(SIGHUP, &action, NULL) < 0 ||
>>> +	    sigaction(SIGUSR1, &action, NULL) < 0 ||
>>> +	    sigaction(SIGUSR2, &action, NULL) < 0 ||
>>> +	    sigaction(SIGCONT, &action, NULL) < 0 ||
>>> +	    sigaction(SIGINT, &action, NULL) < 0) {
>>> +		rte_exit(EXIT_FAILURE, "Could not register signal handler\n");
>>> +	}
>>> +
>>> +	lcore_id = rte_lcore_id();
>>> +
>>> +	if (check_opts_for_help(argc, argv, l2reflect_usage))
>>> +		return 0;
>>> +
>>> +	/* init EAL */
>>> +	ret = rte_eal_init(argc, argv);
>>> +	if (ret < 0)
>>> +		rte_exit(EXIT_FAILURE, "Invalid EAL arguments\n");
>>> +	argc -= ret;
>>> +	argv += ret;
>>> +
>>> +	/* parse application arguments (after the EAL ones) */
>>> +	ret = l2reflect_parse_args(argc, argv);
>>> +	if (ret < 0)
>>> +		rte_exit(EXIT_FAILURE, "Invalid L2REFLECT arguments\n");
>>> +
>>> +	snprintf(mempool_name, sizeof(mempool_name), "mbuf_pool_%d",
>> getpid());
>>> +	RTE_LOG(DEBUG, L2REFLECT, "About to create mempool \"%s\"\n",
>> mempool_name);
>>> +	/* create the mbuf pool */
>>> +	l2reflect_pktmbuf_pool =
>>> +		rte_pktmbuf_pool_create(mempool_name, NB_MBUF,
>>> +			MAX_PKT_BURST, 0, RTE_MBUF_DEFAULT_BUF_SIZE,
>>> +			rte_socket_id());
>>> +
>>> +	if (l2reflect_pktmbuf_pool == NULL)
>>> +		rte_exit(EXIT_FAILURE,
>>> +			 "Cannot init/find mbuf pool name %s\nError: %d
>> %s\n",
>>> +			 mempool_name, rte_errno, rte_strerror(rte_errno));
>>> +
>>> +	nb_ports = rte_eth_dev_count_avail();
>>> +	if (nb_ports == 0)
>>> +		rte_exit(EXIT_FAILURE, "No Ethernet ports - bye\n");
>>> +	if (l2reflect_port_number + 1 > nb_ports)
>>> +		rte_exit(EXIT_FAILURE, "Chosen port %d does not exist -
>> bye\n",
>>> +			 l2reflect_port_number);
>>> +	RTE_LOG(INFO, L2REFLECT, "We have %d ports and will use port %d\n",
>> nb_ports,
>>> +	       l2reflect_port_number);
>>> +
>>> +	rte_eth_dev_info_get(l2reflect_port_number, &dev_info);
>>> +	RTE_LOG(INFO, L2REFLECT, "Initializing port %u ...\n",
>> l2reflect_port_number);
>>> +	fflush(stdout);
>>> +
>>> +	if (l2reflect_interrupt)
>>> +		port_conf.intr_conf.rxq = 1;
>>> +
>>> +	ret = config_port_max_pkt_len(&port_conf, &dev_info);
>>> +	if (ret < 0)
>>> +		rte_exit(EXIT_FAILURE,
>>> +			"Invalid max packet length: %u (port %u)\n",
>>> +			l2reflect_port_number, l2reflect_port_number);
>>> +
>>> +	ret = rte_eth_dev_configure(l2reflect_port_number, 1, 1, &port_conf);
>>> +	if (ret < 0)
>>> +		rte_exit(EXIT_FAILURE,
>>> +			"Cannot configure device: err=%s, port=%u\n",
>>> +			strerror(-ret), l2reflect_port_number);
>>> +
>>> +	ret = rte_eth_dev_adjust_nb_rx_tx_desc(l2reflect_port_number,
>> &nb_rxd, &nb_txd);
>>> +	if (ret != 0)
>>> +		rte_exit(EXIT_FAILURE,
>>> +			 "Cannot adjust # of Rx/Tx descriptors to HW limits:
>> err=%s, port=%u\n",
>>> +			 strerror(-ret), l2reflect_port_number);
>>> +
>>> +	/* init RX queues */
>>> +	for (i = 0; i <= l2reflect_q; i++) {
>>> +		ret = rte_eth_rx_queue_setup(
>>> +			l2reflect_port_number, i, nb_rxd,
>>> +			rte_eth_dev_socket_id(l2reflect_port_number), NULL,
>>> +			l2reflect_pktmbuf_pool);
>>> +		if (ret < 0)
>>> +			rte_exit(
>>> +				EXIT_FAILURE,
>>> +				"rte_eth_rx_queue_setup:err=%s, port=%u
>> q=%u\n",
>>> +				strerror(-ret), l2reflect_port_number, i);
>>> +	}
>>> +
>>> +	/* init one TX queue on each port */
>>> +	txconf = dev_info.default_txconf;
>>> +	txconf.offloads = port_conf.txmode.offloads;
>>> +	ret = rte_eth_tx_queue_setup(
>>> +		l2reflect_port_number, 0, nb_txd,
>>> +		rte_eth_dev_socket_id(l2reflect_port_number), &txconf);
>>> +	if (ret < 0)
>>> +		rte_exit(EXIT_FAILURE,
>>> +			 "rte_eth_tx_queue_setup:err=%s, port=%u\n",
>>> +			 strerror(-ret), (unsigned int)l2reflect_port_number);
>>> +
>>> +	/* Start device */
>>> +	ret = rte_eth_dev_start(l2reflect_port_number);
>>> +	if (ret < 0)
>>> +		rte_exit(EXIT_FAILURE, "rte_eth_dev_start:err=%s, port=%u\n",
>>> +			 strerror(-ret), (unsigned int)l2reflect_port_number);
>>> +
>>> +	rte_eth_macaddr_get(l2reflect_port_number,
>> &l2reflect_port_eth_addr);
>>> +
>>> +	/*
>>> +	 * When running on a Tap device, we might want to use a foreign
>>> +	 * mac address to make sure that the application and the Tap device
>>> +	 * do not share the same MAC addr. By that, we enforce that the
>>> +	 * bridge learns this address and correctly forwards unicast packets.
>>> +	 */
>>> +	if (l2reflect_fake_mac)
>>> +		l2reflect_port_eth_addr.addr_bytes[5] += 1;
>>> +
>>> +	rte_ether_format_addr(mac_str, sizeof(mac_str),
>>> +			      &l2reflect_port_eth_addr);
>>> +	RTE_LOG(INFO, L2REFLECT, "Port %u, MAC address: %s\n\n",
>>> +	       (unsigned int)l2reflect_port_number, mac_str);
>>> +
>>> +	/*
>>> +	 * in quiet mode the primary executes the main packet loop
>>> +	 * otherwise the one worker does it and the primary prints stats
>>> +	 */
>>> +	if (quiet) {
>>> +		assert(rte_lcore_count() == 1);
>>> +#ifdef HAS_SYS_IO
>>> +		if (disable_int) {
>>> +			iopl(3);
>>> +			asm("cli");
>>> +		}
>>> +#endif
>>> +		RTE_LOG(INFO, L2REFLECT, "PID %i, Parent %i\n", getpid(),
>> getppid());
>>> +		l2reflect_launch_one_lcore(NULL);
>>> +	} else {
>>> +		assert(rte_lcore_count() == 2);
>>> +		/* the worker reflects the packets */
>>> +		RTE_LCORE_FOREACH_WORKER(lcore_id)
>>> +		{
>>> +			rte_eal_remote_launch(l2reflect_launch_one_lcore,
>> NULL,
>>> +					      lcore_id);
>>> +		}
>>> +
>>> +		/* the primary prints the stats */
>>> +		init_record();
>>> +		l2reflect_stats_loop();
>>> +		rte_eal_mp_wait_lcore();
>>> +	}
>>> +	rte_eal_cleanup();
>>> +
>>> +	if (l2reflect_hist)
>>> +		output_histogram_snapshot();
>>> +
>>> +	cleanup_record();
>>> +
>>> +	return 0;
>>> +}
>>> diff --git a/app/l2reflect/meson.build b/app/l2reflect/meson.build
>>> new file mode 100644
>>> index 0000000000..14b154ef06
>>> --- /dev/null
>>> +++ b/app/l2reflect/meson.build
>>> @@ -0,0 +1,21 @@
>>> +# SPDX-License-Identifier: BSD-3-Clause
>>> +# Copyright(c) 2022 Siemens AG
>>> +
>>> +cc = meson.get_compiler('c')
>>> +
>>> +jansson = dependency('libjansson', required: false)
>>> +
>>> +if not jansson.found()
>>> +    jansson = cc.find_library('jansson', required: false)
>>> +endif
>>> +
>>> +if cc.has_header('sys/io.h')
>>> +    cflags += '-DHAS_SYS_IO'
>>> +endif
>>> +
>>> +sources = files('main.c', 'utils.c', 'stats.c', 'colors.c')
>>> +deps += ['ethdev']
>>
>> I think some dependecies are missing:
>> ring, mbuf, mempool
>>
>>> +if jansson.found()
>>> +    ext_deps += jansson
>>> +    cflags += '-DRTE_HAS_JANSSON'
>>> +endif
>>> diff --git a/app/l2reflect/payload.h b/app/l2reflect/payload.h
>>> new file mode 100644
>>> index 0000000000..c1fae5d5e4
>>> --- /dev/null
>>> +++ b/app/l2reflect/payload.h
>>> @@ -0,0 +1,26 @@
>>> +/* SPDX-License-Identifier: BSD-3-Clause
>>> + * Copyright(c) 2022 Siemens AG
>>> + */
>>> +#include <rte_ether.h>
>>> +
>>> +#ifndef _L2REFLECT_PAYLOAD_H_
>>> +#define _L2REFLECT_PAYLOAD_H_
>>> +
>>> +#define MAGIC_TRACE_PAYLOAD 0xd00faffeaffed00full
>>> +/* IEEE Std 802 - Local Experimental Ethertype */
>>> +#define ETHER_TYPE_L2REFLECT 0x88B5
>>> +
>>> +struct my_magic_packet {
>>> +	/* l2 packet header */
>>> +	struct rte_ether_hdr eth;
>>> +	/* type of the l2reflect packet */
>>> +	uint8_t type;
>>> +	/* magic easy-to-spot pattern for tracing */
>>> +	uint64_t magic;
>>> +	/* break if latency is larger than this */
>>> +	uint64_t breakval;
>>> +	/* intended size of the packet */
>>> +	uint64_t req_pkt_bytes;
>>> +};
>>> +
>>> +#endif /* _L2REFLECT_PAYLOAD_H_ */
>>> diff --git a/app/l2reflect/stats.c b/app/l2reflect/stats.c
>>> new file mode 100644
>>> index 0000000000..6bcbb7a2bf
>>> --- /dev/null
>>> +++ b/app/l2reflect/stats.c
>>> @@ -0,0 +1,225 @@
>>> +/* SPDX-License-Identifier: BSD-3-Clause
>>> + * Copyright(c) 2020 Siemens AG
>>> + */
>>> +#include <stdio.h>
>>> +#include <sys/types.h>
>>> +#include <unistd.h>
>>> +#include <time.h>
>>> +#include <string.h>
>>> +#ifdef RTE_HAS_JANSSON
>>> +#include <jansson.h>
>>> +#endif
>>> +#include "colors.h"
>>> +#include "stats.h"
>>> +
>>> +unsigned int hist_bucket_usec;
>>> +struct stats record;
>>> +char *hist_filename;
>>> +
>>> +void
>>> +init_record(void)
>>> +{
>>> +	record.max_round_ns = 0;
>>> +	record.min_round_ns = MIN_INITIAL;
>>> +	record.rounds = 0;
>>> +	record.timeouts = 0;
>>> +	record.avg_round_ns = 0;
>>> +	if (l2reflect_hist) {
>>> +		if (!record.hist_size) {
>>> +			record.hist =
>>> +				calloc(l2reflect_hist_buckets, sizeof(uint64_t));
>>> +			record.hist_size = l2reflect_hist_buckets;
>>> +		} else {
>>> +			memset(record.hist, 0,
>>> +			       record.hist_size * sizeof(uint64_t));
>>> +		}
>>> +	}
>>> +	clock_gettime(CLOCK_MONOTONIC, &record.time_start);
>>> +}
>>> +
>>> +void
>>> +cleanup_record(void)
>>> +{
>>> +	if (l2reflect_hist) {
>>> +		free(record.hist);
>>> +		record.hist = NULL;
>>> +		record.hist_size = 0;
>>> +	}
>>> +}
>>> +
>>> +void
>>> +output_histogram_snapshot(void)
>>> +{
>>> +	char *json = serialize_histogram(&record);
>>> +	FILE *fd = stderr;
>>> +	if (hist_filename)
>>> +		fd = fopen(hist_filename, "w");
>>> +	fputs(json, fd);
>>> +	fputs("\n", fd);
>>> +	free(json);
>>> +	if (hist_filename)
>>> +		fclose(fd);
>>> +}
>>> +
>>> +void
>>> +print_stats(void)
>>> +{
>>> +	const char clr[] = { 27, '[', '2', 'J', '\0' };
>>> +	const char topLeft[] = { 27, '[', '1', ';', '1', 'H', '\0' };
>>> +	const uint64_t bytes_in_gib = 0x40000000;
>>> +	struct rte_eth_stats stats;
>>> +	char mac_str_me[RTE_ETHER_ADDR_FMT_SIZE];
>>> +	char mac_str_remote[RTE_ETHER_ADDR_FMT_SIZE];
>>> +	char timeout_bound_str[32];
>>> +	const char *str_jumbo = l2reflect_pkt_bytes > RTE_ETHER_MTU ?
>>> +		"jumbo" : "no-jumbo";
>>> +	struct timespec time_now;
>>> +
>>> +	if (l2reflect_interrupt == 0)
>>> +		snprintf(timeout_bound_str, sizeof(timeout_bound_str), "
>> polling");
>>> +	else if (l2reflect_sleep_msec == -1u)
>>> +		snprintf(timeout_bound_str, sizeof(timeout_bound_str), ">=
>> infinite");
>>> +	else
>>> +		snprintf(timeout_bound_str, sizeof(timeout_bound_str), ">%9"
>> PRIu64 "ms",
>>> +			l2reflect_sleep_msec);
>>> +
>>> +	rte_eth_stats_get(l2reflect_port_number, &stats);
>>> +	rte_ether_format_addr(mac_str_me, sizeof(mac_str_me),
>>> +			      &l2reflect_port_eth_addr);
>>> +	rte_ether_format_addr(mac_str_remote, sizeof(mac_str_remote),
>>> +			      &l2reflect_remote_eth_addr);
>>> +
>>> +	clock_gettime(CLOCK_MONOTONIC, &time_now);
>>> +	const uint64_t time_since_start = time_now.tv_sec -
>> record.time_start.tv_sec;
>>> +
>>> +	/* Clear screen and move to top left */
>>> +	printf("%s%s", clr, topLeft);
>>> +
>>> +	printf("%sNetworking Roundtrip Test%s\n", colors->green, colors-
>>> reset);
>>> +	printf("\n%sPort statistics
>> ====================================%s",
>>> +	       colors->magenta, colors->reset);
>>> +
>>> +	printf("\nMe: %s <--> Remote: %s", mac_str_me, mac_str_remote);
>>> +	printf("\nStatistics for port %d PID %d on lcore %d ---------"
>>> +			"\nState: %-16s %10" PRIu64 " s"
>>> +			"\nPackets tx: %22" PRIu64 "\nPackets rx: %22" PRIu64
>>> +			"\nBytes tx: %24" PRIu64 "    (%8.2f GiB)"
>>> +			"\nBytes rx: %24" PRIu64 "    (%8.2f GiB)"
>>> +			"\nErrors tx: %23" PRIu64 "\nErrors rx: %23" PRIu64
>>> +			"\nTimeouts rx: %21" PRIu64 "    (%s)"
>>> +			"\nPacketsize [Byte]: %15" PRIu64 "    (%12s)",
>>> +			l2reflect_port_number, getpid(), rte_lcore_id(),
>>> +			runstate_tostring(l2reflect_state),
>>> +			time_since_start,
>>> +			stats.opackets, stats.ipackets, stats.obytes,
>>> +			(double)stats.obytes / bytes_in_gib, stats.ibytes,
>>> +			(double)stats.ibytes / bytes_in_gib, stats.oerrors,
>>> +			stats.ierrors, record.timeouts,
>>> +			timeout_bound_str, l2reflect_pkt_bytes, str_jumbo);
>>> +	printf("\n%sPort timing statistics
>> =============================%s",
>>> +	       colors->magenta, colors->reset);
>>> +	if (l2reflect_state == S_ELECT_LEADER ||
>>> +		record.min_round_ns == MIN_INITIAL) {
>>> +		printf("\n\nBenchmark not started yet...\n");
>>> +	} else {
>>> +		printf("\n%sMax%s roundtrip: %19" PRIu64 " us", colors->red,
>>> +		       colors->reset, record.max_round_ns / 1000);
>>> +		printf("\n%sAvg%s roundtrip: %19" PRIu64 " us", colors-
>>> yellow,
>>> +		       colors->reset,
>>> +		       record.rounds ? (uint64_t)(record.avg_round_ns /
>>> +						  record.rounds / 1000) :
>>> +				       0);
>>> +		printf("\n%sMin%s roundtrip: %19" PRIu64 " us", colors->green,
>>> +		       colors->reset, record.min_round_ns / 1000);
>>> +	}
>>> +
>> 	printf("\n%s================================================
>> ====%s\n",
>>> +	       colors->magenta, colors->reset);
>>> +}
>>> +
>>> +void
>>> +l2reflect_stats_loop(void)
>>> +{
>>> +	while (!(l2reflect_state & (S_LOCAL_TERM | S_REMOTE_TERM))) {
>>> +		print_stats();
>>> +		if (l2reflect_hist && l2reflect_output_hist) {
>>> +			output_histogram_snapshot();
>>> +			l2reflect_output_hist = 0;
>>> +		}
>>> +		rte_delay_us_sleep(1000000);
>>> +	}
>>> +}
>>> +
>>> +char *
>>> +serialize_histogram(__rte_unused const struct stats *record)
>>> +{
>>> +#ifndef RTE_HAS_JANSSON
>>> +	return strdup("to print histogram, build with jansson support");
>>> +#else
>>> +	char *str = NULL;
>>> +	char key[8];
>>> +	unsigned int i;
>>> +	json_t *hist0, *cpu0, *all_cpus, *output;
>>> +
>>> +	output = json_object();
>>> +	/* version: 1 */
>>> +	json_object_set_new(output, "version", json_integer(1));
>>> +
>>> +	/* cpu 0 histogram */
>>> +	hist0 = json_object();
>>> +	for (i = 0; i < record->hist_size; ++i) {
>>> +		/* only log positive numbers to meet jitterplot format */
>>> +		if (record->hist[i] != 0) {
>>> +			snprintf(key, 8, "%u", i * hist_bucket_usec);
>>> +			json_object_set(hist0, key,
>>> +					json_integer(record->hist[i]));
>>> +		}
>>> +	}
>>> +
>>> +	/* in case of empty histogram, set these values to zero */
>>> +	const json_int_t min_round_us =
>>> +		record->rounds ? record->min_round_ns / 1000 : 0;
>>> +	const json_int_t avg_round_us =
>>> +		record->rounds ? record->avg_round_ns / record->rounds /
>> 1000 : 0;
>>> +	const json_int_t max_round_us =
>>> +		record->rounds ? record->max_round_ns / 1000 : 0;
>>> +
>>> +	/* cpu 0 stats */
>>> +	cpu0 = json_object();
>>> +	json_object_set_new(cpu0, "histogram", hist0);
>>> +	json_object_set_new(cpu0, "count", json_integer(record->rounds));
>>> +	json_object_set_new(cpu0, "min", json_integer(min_round_us));
>>> +	json_object_set_new(cpu0, "max", json_integer(max_round_us));
>>> +	json_object_set_new(cpu0, "avg", json_integer(avg_round_us));
>>> +
>>> +	/* combine objects */
>>> +	all_cpus = json_object();
>>> +	json_object_set_new(all_cpus, "0", cpu0);
>>> +	json_object_set_new(output, "cpu", all_cpus);
>>> +
>>> +	str = json_dumps(output, JSON_ENSURE_ASCII | JSON_INDENT(2));
>>> +
>>> +	/* cleanup */
>>> +	json_decref(output);
>>> +
>>> +	return str;
>>> +#endif
>>> +}
>>> +
>>> +const char *
>>> +runstate_tostring(int s)
>>> +{
>>> +	switch (s) {
>>> +	case S_ELECT_LEADER:
>>> +		return "Electing";
>>> +	case S_RESET_TRX:
>>> +		return "Resetting";
>>> +	case S_RUNNING:
>>> +		return "Running";
>>> +	case S_LOCAL_TERM:
>>> +		return "Term. local";
>>> +	case S_REMOTE_TERM:
>>> +		return "Term. remote";
>>> +	default:
>>> +		return "Preparing";
>>> +	}
>>> +}
>>> diff --git a/app/l2reflect/stats.h b/app/l2reflect/stats.h
>>> new file mode 100644
>>> index 0000000000..7f3dd9fffb
>>> --- /dev/null
>>> +++ b/app/l2reflect/stats.h
>>> @@ -0,0 +1,67 @@
>>> +/* SPDX-License-Identifier: BSD-3-Clause
>>> + * Copyright(c) 2020 Siemens AG
>>> + */
>>> +#ifndef _L2REFLECT_STATS_H_
>>> +#define _L2REFLECT_STATS_H_
>>> +#include <stdint.h>
>>> +#include <stdatomic.h>
>>> +#include <limits.h>
>>> +
>>> +#include <rte_ethdev.h>
>>> +
>>> +#include "l2reflect.h"
>>> +
>>> +#define MIN_INITIAL ULONG_MAX
>>> +#define HIST_NUM_BUCKETS_DEFAULT 128
>>> +
>>> +/* runtime statistics */
>>> +struct stats {
>>> +	uint64_t max_round_ns;
>>> +	uint64_t min_round_ns;
>>> +	uint64_t rounds;
>>> +	uint64_t timeouts;
>>> +	double avg_round_ns;
>>> +	unsigned int hist_size;
>>> +	/* each slot is 10us */
>>> +	uint64_t *hist;
>>> +	struct timespec time_start;
>>> +};
>>> +
>>> +/* size of each histogram bucket in usec */
>>> +extern unsigned int hist_bucket_usec;
>>> +extern struct stats record;
>>> +extern char *hist_filename;
>>> +
>>> +void
>>> +init_record(void);
>>> +void
>>> +cleanup_record(void);
>>> +
>>> +void
>>> +l2reflect_stats_loop(void);
>>> +
>>> +/*
>>> + * Write the histogram to file / stdio without any locking.
>>> + * When called during the measurement, values are approximations
>>> + * (racy reads).
>>> + */
>>> +void
>>> +output_histogram_snapshot(void);
>>> +
>>> +/* Print out statistics on packets dropped */
>>> +void
>>> +print_stats(void);
>>> +
>>> +/*
>>> + * get a JSON representation of the record
>>> + */
>>> +char *
>>> +serialize_histogram(const struct stats *record);
>>> +
>>> +/*
>>> + * get a string representation of the current runstate
>>> + */
>>> +const char *
>>> +runstate_tostring(int s);
>>> +
>>> +#endif /* _L2REFLECT_STATS_H_ */
>>> diff --git a/app/l2reflect/utils.c b/app/l2reflect/utils.c
>>> new file mode 100644
>>> index 0000000000..4116b986d2
>>> --- /dev/null
>>> +++ b/app/l2reflect/utils.c
>>> @@ -0,0 +1,67 @@
>>> +/* SPDX-License-Identifier: BSD-3-Clause
>>> + * Copyright(c) 2021 Siemens AG
>>> + */
>>> +
>>> +#include <rte_ethdev.h>
>>> +#include <rte_log.h>
>>> +#include <rte_ethdev.h>
>>> +
>>> +#include "utils.h"
>>> +#include "l2reflect.h"
>>> +
>>> +void
>>> +assert_link_status(int port_id)
>>> +{
>>> +	struct rte_eth_link link;
>>> +	uint8_t rep_cnt = MAX_REPEAT_TIMES;
>>> +	int link_get_err = -EINVAL;
>>> +
>>> +	memset(&link, 0, sizeof(link));
>>> +	do {
>>> +		link_get_err = rte_eth_link_get_nowait(port_id, &link);
>>> +		if (link_get_err == 0 && link.link_status == RTE_ETH_LINK_UP)
>>> +			break;
>>> +		rte_delay_ms(CHECK_INTERVAL);
>>> +		RTE_LOG(INFO, L2REFLECT, "Link not ready yet, try again...\n");
>>> +	} while (--rep_cnt && (l2reflect_state != S_LOCAL_TERM));
>>> +
>>> +	if (link_get_err < 0)
>>> +		rte_exit(EXIT_FAILURE, "error: link get is failing: %s\n",
>>> +			 rte_strerror(-link_get_err));
>>> +	if (link.link_status == RTE_ETH_LINK_DOWN)
>>> +		rte_exit(EXIT_FAILURE, "error: link is still down\n");
>>> +
>>> +	const char *linkspeed_str = rte_eth_link_speed_to_str(link.link_speed);
>>> +	RTE_LOG(INFO, L2REFLECT,
>>> +		"Link status on port %d: speed: %s, duplex: %s\n",
>>> +		port_id, linkspeed_str,
>>> +		link.link_duplex == RTE_ETH_LINK_FULL_DUPLEX ? "full" :
>> "half");
>>> +}
>>> +
>>> +uint32_t
>>> +eth_dev_get_overhead_len(uint32_t max_rx_pktlen, uint16_t max_mtu)
>>> +{
>>> +	uint32_t overhead_len;
>>> +	if (max_mtu != UINT16_MAX && max_rx_pktlen > max_mtu)
>>> +		overhead_len = max_rx_pktlen - max_mtu;
>>> +	else
>>> +		overhead_len = RTE_ETHER_HDR_LEN + RTE_ETHER_CRC_LEN;
>>> +	return overhead_len;
>>> +}
>>> +
>>> +int
>>> +config_port_max_pkt_len(struct rte_eth_conf *conf,
>>> +						struct rte_eth_dev_info
>> *dev_info)
>>> +{
>>> +	uint32_t overhead_len;
>>> +	if (l2reflect_pkt_bytes < RTE_ETHER_MIN_LEN ||
>>> +		l2reflect_pkt_bytes > MAX_JUMBO_PKT_LEN)
>>> +		return -1;
>>> +	overhead_len = eth_dev_get_overhead_len(dev_info->max_rx_pktlen,
>>> +		dev_info->max_mtu);
>>> +	conf->rxmode.mtu = MAX(l2reflect_pkt_bytes - overhead_len,
>>> +			       dev_info->min_mtu);
>>> +	if (conf->rxmode.mtu > RTE_ETHER_MTU)
>>> +		conf->txmode.offloads |=
>> RTE_ETH_TX_OFFLOAD_MULTI_SEGS;
>>> +	return 0;
>>> +}
>>> diff --git a/app/l2reflect/utils.h b/app/l2reflect/utils.h
>>> new file mode 100644
>>> index 0000000000..177ad8cda6
>>> --- /dev/null
>>> +++ b/app/l2reflect/utils.h
>>> @@ -0,0 +1,20 @@
>>> +/* SPDX-License-Identifier: BSD-3-Clause
>>> + * Copyright(c) 2021 Siemens AG
>>> + */
>>> +
>>> +#ifndef _L2REFLECT_UTILS_H_
>>> +#define _L2REFLECT_UTILS_H_
>>> +
>>> +#define MAX_REPEAT_TIMES 30
>>> +#define CHECK_INTERVAL 2000
>>> +
>>> +void assert_link_status(int port_id);
>>> +
>>> +uint32_t
>>> +eth_dev_get_overhead_len(uint32_t max_rx_pktlen, uint16_t max_mtu);
>>> +
>>> +int
>>> +config_port_max_pkt_len(struct rte_eth_conf *conf,
>>> +			struct rte_eth_dev_info *dev_info);
>>> +
>>> +#endif /* _L2REFLECT_UTILS_H_ */
>>> diff --git a/app/meson.build b/app/meson.build
>>> index 0ea04cadeb..3593322ab2 100644
>>> --- a/app/meson.build
>>> +++ b/app/meson.build
>>> @@ -3,6 +3,7 @@
>>>
>>>    apps = [
>>>            'dumpcap',
>>> +        'l2reflect',
>>>            'pdump',
>>>            'proc-info',
>>>            'test-acl',
>