DPDK logo

Elixir Cross Referencer

/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2010-2017 Intel Corporation
 */

#include "test.h"

#include <unistd.h>
#include <string.h>
#include <rte_mempool.h>
#include <rte_cycles.h>
#include <rte_common.h>
#include <rte_mbuf.h>
#include <rte_distributor.h>
#include <rte_pause.h>

#define ITER_POWER_CL 25 /* log 2 of how many iterations  for Cache Line test */
#define ITER_POWER 21 /* log 2 of how many iterations we do when timing. */
#define BURST 64
#define BIG_BATCH 1024

/* static vars - zero initialized by default */
static volatile int quit;
static volatile unsigned worker_idx;

struct worker_stats {
	volatile unsigned handled_packets;
} __rte_cache_aligned;
static struct worker_stats worker_stats[RTE_MAX_LCORE];

/*
 * worker thread used for testing the time to do a round-trip of a cache
 * line between two cores and back again
 */
static int
flip_bit(volatile uint64_t *arg)
{
	uint64_t old_val = 0;
	while (old_val != 2) {
		while (!*arg)
			rte_pause();
		old_val = *arg;
		*arg = 0;
	}
	return 0;
}

/*
 * test case to time the number of cycles to round-trip a cache line between
 * two cores and back again.
 */
static void
time_cache_line_switch(void)
{
	/* allocate a full cache line for data, we use only first byte of it */
	uint64_t data[RTE_CACHE_LINE_SIZE*3 / sizeof(uint64_t)];

	unsigned i, slaveid = rte_get_next_lcore(rte_lcore_id(), 0, 0);
	volatile uint64_t *pdata = &data[0];
	*pdata = 1;
	rte_eal_remote_launch((lcore_function_t *)flip_bit, &data[0], slaveid);
	while (*pdata)
		rte_pause();

	const uint64_t start_time = rte_rdtsc();
	for (i = 0; i < (1 << ITER_POWER_CL); i++) {
		while (*pdata)
			rte_pause();
		*pdata = 1;
	}
	const uint64_t end_time = rte_rdtsc();

	while (*pdata)
		rte_pause();
	*pdata = 2;
	rte_eal_wait_lcore(slaveid);
	printf("==== Cache line switch test ===\n");
	printf("Time for %u iterations = %"PRIu64" ticks\n", (1<<ITER_POWER_CL),
			end_time-start_time);
	printf("Ticks per iteration = %"PRIu64"\n\n",
			(end_time-start_time) >> ITER_POWER_CL);
}

/*
 * returns the total count of the number of packets handled by the worker
 * functions given below.
 */
static unsigned
total_packet_count(void)
{
	unsigned i, count = 0;
	for (i = 0; i < worker_idx; i++)
		count += worker_stats[i].handled_packets;
	return count;
}

/* resets the packet counts for a new test */
static void
clear_packet_count(void)
{
	memset(&worker_stats, 0, sizeof(worker_stats));
}

/*
 * This is the basic worker function for performance tests.
 * it does nothing but return packets and count them.
 */
static int
handle_work(void *arg)
{
	struct rte_distributor *d = arg;
	unsigned int count = 0;
	unsigned int num = 0;
	int i;
	unsigned int id = __atomic_fetch_add(&worker_idx, 1, __ATOMIC_RELAXED);
	struct rte_mbuf *buf[8] __rte_cache_aligned;

	for (i = 0; i < 8; i++)
		buf[i] = NULL;

	num = rte_distributor_get_pkt(d, id, buf, buf, num);
	while (!quit) {
		worker_stats[id].handled_packets += num;
		count += num;
		num = rte_distributor_get_pkt(d, id, buf, buf, num);
	}
	worker_stats[id].handled_packets += num;
	count += num;
	rte_distributor_return_pkt(d, id, buf, num);
	return 0;
}

/*
 * This basic performance test just repeatedly sends in 32 packets at a time
 * to the distributor and verifies at the end that we got them all in the worker
 * threads and finally how long per packet the processing took.
 */
static inline int
perf_test(struct rte_distributor *d, struct rte_mempool *p)
{
	unsigned int i;
	uint64_t start, end;
	struct rte_mbuf *bufs[BURST];

	clear_packet_count();
	if (rte_mempool_get_bulk(p, (void *)bufs, BURST) != 0) {
		printf("Error getting mbufs from pool\n");
		return -1;
	}
	/* ensure we have different hash value for each pkt */
	for (i = 0; i < BURST; i++)
		bufs[i]->hash.usr = i;

	start = rte_rdtsc();
	for (i = 0; i < (1<<ITER_POWER); i++)
		rte_distributor_process(d, bufs, BURST);
	end = rte_rdtsc();

	do {
		usleep(100);
		rte_distributor_process(d, NULL, 0);
	} while (total_packet_count() < (BURST << ITER_POWER));

	rte_distributor_clear_returns(d);

	printf("Time per burst:  %"PRIu64"\n", (end - start) >> ITER_POWER);
	printf("Time per packet: %"PRIu64"\n\n",
			((end - start) >> ITER_POWER)/BURST);
	rte_mempool_put_bulk(p, (void *)bufs, BURST);

	for (i = 0; i < rte_lcore_count() - 1; i++)
		printf("Worker %u handled %u packets\n", i,
				worker_stats[i].handled_packets);
	printf("Total packets: %u (%x)\n", total_packet_count(),
			total_packet_count());
	printf("=== Perf test done ===\n\n");

	return 0;
}

/* Useful function which ensures that all worker functions terminate */
static void
quit_workers(struct rte_distributor *d, struct rte_mempool *p)
{
	const unsigned int num_workers = rte_lcore_count() - 1;
	unsigned int i;
	struct rte_mbuf *bufs[RTE_MAX_LCORE];

	rte_mempool_get_bulk(p, (void *)bufs, num_workers);

	quit = 1;
	for (i = 0; i < num_workers; i++)
		bufs[i]->hash.usr = i << 1;
	rte_distributor_process(d, bufs, num_workers);

	rte_mempool_put_bulk(p, (void *)bufs, num_workers);

	rte_distributor_process(d, NULL, 0);
	rte_eal_mp_wait_lcore();
	quit = 0;
	worker_idx = 0;
}

static int
test_distributor_perf(void)
{
	static struct rte_distributor *ds;
	static struct rte_distributor *db;
	static struct rte_mempool *p;

	if (rte_lcore_count() < 2) {
		printf("Not enough cores for distributor_perf_autotest, expecting at least 2\n");
		return TEST_SKIPPED;
	}

	/* first time how long it takes to round-trip a cache line */
	time_cache_line_switch();

	if (ds == NULL) {
		ds = rte_distributor_create("Test_perf", rte_socket_id(),
				rte_lcore_count() - 1,
				RTE_DIST_ALG_SINGLE);
		if (ds == NULL) {
			printf("Error creating distributor\n");
			return -1;
		}
	} else {
		rte_distributor_clear_returns(ds);
	}

	if (db == NULL) {
		db = rte_distributor_create("Test_burst", rte_socket_id(),
				rte_lcore_count() - 1,
				RTE_DIST_ALG_BURST);
		if (db == NULL) {
			printf("Error creating burst distributor\n");
			return -1;
		}
	} else {
		rte_distributor_clear_returns(db);
	}

	const unsigned nb_bufs = (511 * rte_lcore_count()) < BIG_BATCH ?
			(BIG_BATCH * 2) - 1 : (511 * rte_lcore_count());
	if (p == NULL) {
		p = rte_pktmbuf_pool_create("DPT_MBUF_POOL", nb_bufs, BURST,
			0, RTE_MBUF_DEFAULT_BUF_SIZE, rte_socket_id());
		if (p == NULL) {
			printf("Error creating mempool\n");
			return -1;
		}
	}

	printf("=== Performance test of distributor (single mode) ===\n");
	rte_eal_mp_remote_launch(handle_work, ds, SKIP_MASTER);
	if (perf_test(ds, p) < 0)
		return -1;
	quit_workers(ds, p);

	printf("=== Performance test of distributor (burst mode) ===\n");
	rte_eal_mp_remote_launch(handle_work, db, SKIP_MASTER);
	if (perf_test(db, p) < 0)
		return -1;
	quit_workers(db, p);

	return 0;
}

REGISTER_TEST_COMMAND(distributor_perf_autotest, test_distributor_perf);