SPDK和DPDK（Data Plane Development Kit）协同工作的代码案例-DPDK中文网

以下是一个使用SPDK和DPDK协同工作的代码案例：

#include <stdio.h>
#include <stdint.h>
#include <string.h>

#include <rte_config.h>
#include <rte_eal.h>
#include <rte_mbuf.h>

#include "spdk/stdinc.h"
#include "spdk/env_dpdk.h"
#include "spdk/nvme.h"

#define MAX_MBUFS 8192
#define MBUF_CACHE_SIZE 256

static struct rte_mempool *mbuf_pool;

static void nvme_read(struct spdk_nvme_qpair *qpair, uint64_t lba,
                      uint32_t lba_count, struct rte_mbuf **mbufs)
{
    int i;
    int rc;
    uint32_t n_reqs = (lba_count + mbuf_pool->elt_size - 1) / mbuf_pool->elt_size;

    for (i = 0; i < n_reqs; ++i) {
        struct rte_mbuf *mbuf = rte_pktmbuf_alloc(mbuf_pool);
        if (!mbuf) {
            fprintf(stderr, "Unable to allocate mbuf\n");
            return;
        }

        mbufs[i] = mbuf;

        rc = spdk_nvme_ns_cmd_read(qpair, rte_pktmbuf_mtod(mbuf, void*),
                                   lba + i*mbuf_pool->elt_size/512,
                                   mbuf_pool->elt_size/512,
                                   NULL, 0, 0);
        if (rc != SPDK_NVME_SC_SUCCESS) {
            fprintf(stderr, "Error %d on read command\n", rc);
            return;
        }
    }

    while (spdk_nvme_qpair_process_completions(qpair, n_reqs) != n_reqs);
}

int main(int argc, char **argv)
{
    int ret;
    struct spdk_env_opts opts;
    struct rte_mbuf *mbufs[MAX_MBUFS];
    uint64_t lba = 0;
    uint32_t lba_count = MAX_MBUFS*MBUF_CACHE_SIZE/512;

    memset(&opts, 0, sizeof(opts));
    opts.name = "spdk_dpdk_test";
    opts.core_mask = "0x1";
    spdk_env_dpdk_init(&opts);

    ret = rte_eal_init(argc, argv);
    if (ret < 0) {
        fprintf(stderr, "Failed to initialize DPDK EAL\n");
        return -1;
   }

   mbuf_pool = rte_pktmbuf_pool_create("mbuf_pool", MAX_MBUFS,
                                       MBUF_CACHE_SIZE, 0,
                                       RTE_MBUF_DEFAULT_BUF_SIZE,
                                       rte_socket_id());
   if (!mbuf_pool) {
       fprintf(stderr, "Failed to create mbuf pool\n");
       return -1;
   }

   struct spdk_nvme_ctrlr *ctrlr;
   ctrlr = spdk_nvme_connect("nvme0", NULL);
   if (!ctrlr) {
       fprintf(stderr, "Unable to connect to NVMe controller\n");
       return -1;
   }

   uint32_t nsid = spdk_nvme_ctrlr_get_first_active_ns(ctrlr);
   struct spdk_nvme_ns *ns = spdk_nvme_ctrlr_get_ns(ctrlr, nsid);

   struct spdk_nvme_qpair *qpair =
           spdk_nvme_ctrlr_alloc_io_qpair(ctrlr, NULL, 0);
   if (!qpair) {
       fprintf(stderr, "Unable to allocate IO queue pair\n");
       return -1;
   }

   while (lba < lba_count) {
       nvme_read(qpair, lba, MBUF_CACHE_SIZE/512, mbufs);

       int i;
       for (i = 0; i < MAX_MBUFS && lba < lba_count; ++i) {
           struct rte_mbuf *mbuf = mbufs[i];

           uint64_t offset = (lba % (MBUF_CACHE_SIZE/512)) *
                             BLOCK_SIZE;

           printf("LBA %lu: %x\n", lba,
                  *(uint32_t*)(rte_pktmbuf_mtod(mbuf, char*) + offset));

           rte_pktmbuf_free(mbuf);
           ++lba;
      }
   }

   spdk_nvme_ctrlr_free_io_qpair(qpair);
   spdk_nvme_detach(ctrlr);

   return 0;
}

该代码案例使用SPDK和DPDK协同工作，从NVMe设备中读取数据。它首先初始化SPDK环境和DPDK环境，并创建一个用于存储网络包的内存池。之后，它连接到NVMe设备控制器并分配一个I/O队列对。然后，它循环执行读操作，每次处理MBUF_CACHE_SIZE逻辑块地址(LBA)，直到处理完整个磁盘的所有LBA。在每次迭代中，它调用nvme_read函数进行一组读操作，并将结果存储在内存池中的mbufs数组中。最后，它遍历mbufs数组并打印出每个逻辑块的内容。

该代码案例演示了如何使用SPDK和DPDK协同工作，并从NVMe设备中读取数据。它还展示了如何使用内存池和网络包来处理数据。