dpdk example——rxtx_callbacks

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代码和skeleton类似
/*-
 * BSD LICENSE
 *
 * Copyright(c) 2010-2015 Intel Corporation. All rights reserved.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in
 * the documentation and/or other materials provided with the
 * distribution.
 * * Neither the name of Intel Corporation nor the names of its
 * contributors may be used to endorse or promote products derived
 * from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdint.h>
#include <inttypes.h>
#include <rte_eal.h>
#include <rte_ethdev.h>
#include <rte_cycles.h>
#include <rte_lcore.h>
#include <rte_mbuf.h>

#define RX_RING_SIZE 128
#define TX_RING_SIZE 512

#define NUM_MBUFS 8191
#define MBUF_CACHE_SIZE 250
#define BURST_SIZE 32

static const struct rte_eth_conf port_conf_default = {
 .rxmode = { .max_rx_pkt_len = ETHER_MAX_LEN, },
};

static unsigned nb_ports;

static struct {
 uint64_t total_cycles;
 uint64_t total_pkts;
} latency_numbers;


static uint16_t
add_timestamps(uint8_t port __rte_unused, uint16_t qidx __rte_unused,
  struct rte_mbuf **pkts, uint16_t nb_pkts,
  uint16_t max_pkts __rte_unused, void *_ __rte_unused)
{
 unsigned i;
 uint64_t now = rte_rdtsc();

 for (i = 0; i < nb_pkts; i++)
  pkts[i]->udata64 = now;
 return nb_pkts;
}

static uint16_t
calc_latency(uint8_t port __rte_unused, uint16_t qidx __rte_unused,
  struct rte_mbuf **pkts, uint16_t nb_pkts, void *_ __rte_unused)
{
 uint64_t cycles = 0;
 uint64_t now = rte_rdtsc();
 unsigned i;

 for (i = 0; i < nb_pkts; i++)
  cycles += now - pkts[i]->udata64;
 latency_numbers.total_cycles += cycles;
 latency_numbers.total_pkts += nb_pkts;

 // 这里打印出来的数据需要除以主频率，的出来的值的单位为s
 if (latency_numbers.total_pkts > (100 * 1000 * 1000ULL)) {
  printf("Latency = %"PRIu64" cycles\n",
  latency_numbers.total_cycles / latency_numbers.total_pkts);
  latency_numbers.total_cycles = latency_numbers.total_pkts = 0;
 }
 return nb_pkts;
}

/*
 * Initialises a given port using global settings and with the rx buffers
 * coming from the mbuf_pool passed as parameter
 */
static inline int
port_init(uint8_t port, struct rte_mempool *mbuf_pool)
{
 struct rte_eth_conf port_conf = port_conf_default;
 const uint16_t rx_rings = 1, tx_rings = 1;
 int retval;
 uint16_t q;

 if (port >= rte_eth_dev_count())
  return -1;

 retval = rte_eth_dev_configure(port, rx_rings, tx_rings, &port_conf);
 if (retval != 0)
  return retval;

 for (q = 0; q < rx_rings; q++) {
  retval = rte_eth_rx_queue_setup(port, q, RX_RING_SIZE,
    rte_eth_dev_socket_id(port), NULL, mbuf_pool);
  if (retval < 0)
   return retval;
 }

 for (q = 0; q < tx_rings; q++) {
  retval = rte_eth_tx_queue_setup(port, q, TX_RING_SIZE,
    rte_eth_dev_socket_id(port), NULL);
  if (retval < 0)
   return retval;
 }

 retval = rte_eth_dev_start(port);
 if (retval < 0)
  return retval;

 struct ether_addr addr;

 rte_eth_macaddr_get(port, &addr);
 printf("Port %u MAC: %02"PRIx8" %02"PRIx8" %02"PRIx8
   " %02"PRIx8" %02"PRIx8" %02"PRIx8"\n",
   (unsigned)port,
   addr.addr_bytes[0], addr.addr_bytes[1],
   addr.addr_bytes[2], addr.addr_bytes[3],
   addr.addr_bytes[4], addr.addr_bytes[5]);

 rte_eth_promiscuous_enable(port);

 /* 在收包和发包的地方设置回调函数 */
 rte_eth_add_rx_callback(port, 0, add_timestamps, NULL);
 rte_eth_add_tx_callback(port, 0, calc_latency, NULL);

 return 0;
}

/*
 * Main thread that does the work, reading from INPUT_PORT
 * and writing to OUTPUT_PORT
 */
static __attribute__((noreturn)) void
lcore_main(void)
{
 uint8_t port;

 for (port = 0; port < nb_ports; port++)
  if (rte_eth_dev_socket_id(port) > 0 &&
    rte_eth_dev_socket_id(port) !=
      (int)rte_socket_id())
   printf("WARNING, port %u is on remote NUMA node to "
     "polling thread.\n\tPerformance will "
     "not be optimal.\n", port);

 printf("\nCore %u forwarding packets. [Ctrl+C to quit]\n",
   rte_lcore_id());
 for (;;) {
  for (port = 0; port < nb_ports; port++) {
   struct rte_mbuf *bufs[BURST_SIZE];
   const uint16_t nb_rx = rte_eth_rx_burst(port, 0,
     bufs, BURST_SIZE);
   if (unlikely(nb_rx == 0))
    continue;
   const uint16_t nb_tx = rte_eth_tx_burst(port ^ 1, 0,
     bufs, nb_rx);
   if (unlikely(nb_tx < nb_rx)) {
    uint16_t buf;

    for (buf = nb_tx; buf < nb_rx; buf++)
     rte_pktmbuf_free(bufs[buf]);
   }
  }
 }
}

/* Main function, does initialisation and calls the per-lcore functions */
int
main(int argc, char *argv[])
{
    char* name = "/sys/fs/cgroup/cpuset/tasks";
    FILE* globaltask = NULL;
    globaltask = fopen(name,"a");
    int pid = getpid();
    if(globaltask) {
        fprintf(globaltask,"%d\n",pid);
        fclose(globaltask);
    }

 struct rte_mempool *mbuf_pool;
 uint8_t portid;

 /* init EAL */
 int ret = rte_eal_init(argc, argv);

 if (ret < 0)
  rte_exit(EXIT_FAILURE, "Error with EAL initialization\n");
 argc -= ret;
 argv += ret;

 nb_ports = rte_eth_dev_count();
 if (nb_ports < 2 || (nb_ports & 1))
  rte_exit(EXIT_FAILURE, "Error: number of ports must be even\n");

 mbuf_pool = rte_pktmbuf_pool_create("MBUF_POOL",
  NUM_MBUFS * nb_ports, MBUF_CACHE_SIZE, 0,
  RTE_MBUF_DEFAULT_BUF_SIZE, rte_socket_id());
 if (mbuf_pool == NULL)
  rte_exit(EXIT_FAILURE, "Cannot create mbuf pool\n");

 /* initialize all ports */
 for (portid = 0; portid < nb_ports; portid++)
  if (port_init(portid, mbuf_pool) != 0)
   rte_exit(EXIT_FAILURE, "Cannot init port %"PRIu8"\n",
     portid);

 if (rte_lcore_count() > 1)
  printf("\nWARNING: Too much enabled lcores - "
   "App uses only 1 lcore\n");

 /* call lcore_main on master core only */
 lcore_main();
 return 0;
}

result:
WARNING: Too much enabled lcores - App uses only 1 lcore

Core 0 forwarding packets. [Ctrl+C to quit]
Latency = 237 cycles
Latency = 180 cycles
在收包的时候计算时间戳，在发包的时候进行计算处理时间
得出来的值需要除以cpu主频率，然后的出来的值单位微妙
该值为代表包的转发性能
dpdk example——rxtx_callbacks

代码分析

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