examples/dma: add force minimal copy size parameter

This patch adds force minimal copy size parameter
(-m/--force-min-copy-size), so when do copy by CPU or DMA, the real copy
size will be the maximum of mbuf's data_len and this parameter.

This parameter was designed to compare the performance between CPU copy
and DMA copy. User could send small packets with a high rate to drive
the performance test.

Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Kevin Laatz <kevin.laatz@intel.com>

diff --git a/examples/dma/dmafwd.c b/examples/dma/dmafwd.c
index dd576bcf776de8b5d0fdf3a80cfe03b56eb40ace..67b5a9b22b896edfd166fbeb463fc6d1c35e6def 100644 (file)
--- a/examples/dma/dmafwd.c
+++ b/examples/dma/dmafwd.c
@@ -25,6 +25,7 @@
 #define CMD_LINE_OPT_RING_SIZE "ring-size"
 #define CMD_LINE_OPT_BATCH_SIZE "dma-batch-size"
 #define CMD_LINE_OPT_FRAME_SIZE "max-frame-size"
+#define CMD_LINE_OPT_FORCE_COPY_SIZE "force-min-copy-size"
 #define CMD_LINE_OPT_STATS_INTERVAL "stats-interval"
 
 /* configurable number of RX/TX ring descriptors */
@@ -118,6 +119,7 @@ static volatile bool force_quit;
 
 static uint32_t dma_batch_sz = MAX_PKT_BURST;
 static uint32_t max_frame_size;
+static uint32_t force_min_copy_size;
 
 /* ethernet addresses of ports */
 static struct rte_ether_addr dma_ports_eth_addr[RTE_MAX_ETHPORTS];
@@ -205,7 +207,13 @@ print_stats(char *prgname)
                "Rx Queues = %d, ", nb_queues);
        status_strlen += snprintf(status_string + status_strlen,
                sizeof(status_string) - status_strlen,
-               "Ring Size = %d", ring_size);
+               "Ring Size = %d\n", ring_size);
+       status_strlen += snprintf(status_string + status_strlen,
+               sizeof(status_string) - status_strlen,
+               "Force Min Copy Size = %u Packet Data Room Size = %u",
+               force_min_copy_size,
+               rte_pktmbuf_data_room_size(dma_pktmbuf_pool) -
+               RTE_PKTMBUF_HEADROOM);
 
        memset(&ts, 0, sizeof(struct total_statistics));
 
@@ -303,7 +311,8 @@ static inline void
 pktmbuf_sw_copy(struct rte_mbuf *src, struct rte_mbuf *dst)
 {
        rte_memcpy(rte_pktmbuf_mtod(dst, char *),
-               rte_pktmbuf_mtod(src, char *), src->data_len);
+               rte_pktmbuf_mtod(src, char *),
+               RTE_MAX(src->data_len, force_min_copy_size));
 }
 /* >8 End of perform packet copy there is a user-defined function. */
 
@@ -320,7 +329,9 @@ dma_enqueue_packets(struct rte_mbuf *pkts[], struct rte_mbuf *pkts_copy[],
                ret = rte_dma_copy(dev_id, 0,
                        rte_pktmbuf_iova(pkts[i]),
                        rte_pktmbuf_iova(pkts_copy[i]),
-                       rte_pktmbuf_data_len(pkts[i]), 0);
+                       RTE_MAX(rte_pktmbuf_data_len(pkts[i]),
+                               force_min_copy_size),
+                       0);
 
                if (ret < 0)
                        break;
@@ -572,6 +583,7 @@ dma_usage(const char *prgname)
        printf("%s [EAL options] -- -p PORTMASK [-q NQ]\n"
                "  -b --dma-batch-size: number of requests per DMA batch\n"
                "  -f --max-frame-size: max frame size\n"
+               "  -m --force-min-copy-size: force a minimum copy length, even for smaller packets\n"
                "  -p --portmask: hexadecimal bitmask of ports to configure\n"
                "  -q NQ: number of RX queues per port (default is 1)\n"
                "  --[no-]mac-updating: Enable or disable MAC addresses updating (enabled by default)\n"
@@ -617,6 +629,7 @@ dma_parse_args(int argc, char **argv, unsigned int nb_ports)
                "b:"  /* dma batch size */
                "c:"  /* copy type (sw|hw) */
                "f:"  /* max frame size */
+               "m:"  /* force min copy size */
                "p:"  /* portmask */
                "q:"  /* number of RX queues per port */
                "s:"  /* ring size */
@@ -632,6 +645,7 @@ dma_parse_args(int argc, char **argv, unsigned int nb_ports)
                {CMD_LINE_OPT_RING_SIZE, required_argument, NULL, 's'},
                {CMD_LINE_OPT_BATCH_SIZE, required_argument, NULL, 'b'},
                {CMD_LINE_OPT_FRAME_SIZE, required_argument, NULL, 'f'},
+               {CMD_LINE_OPT_FORCE_COPY_SIZE, required_argument, NULL, 'm'},
                {CMD_LINE_OPT_STATS_INTERVAL, required_argument, NULL, 'i'},
                {NULL, 0, 0, 0}
        };
@@ -666,6 +680,10 @@ dma_parse_args(int argc, char **argv, unsigned int nb_ports)
                        }
                        break;
 
+               case 'm':
+                       force_min_copy_size = atoi(optarg);
+                       break;
+
                /* portmask */
                case 'p':
                        dma_enabled_port_mask = dma_parse_portmask(optarg);
@@ -1064,6 +1082,12 @@ main(int argc, char **argv)
                rte_exit(EXIT_FAILURE, "Cannot init mbuf pool\n");
        /* >8 End of allocates mempool to hold the mbufs. */
 
+       if (force_min_copy_size >
+               (uint32_t)(rte_pktmbuf_data_room_size(dma_pktmbuf_pool) -
+                          RTE_PKTMBUF_HEADROOM))
+               rte_exit(EXIT_FAILURE,
+                        "Force min copy size > packet mbuf size\n");
+
        /* Initialize each port. 8< */
        cfg.nb_ports = 0;
        RTE_ETH_FOREACH_DEV(portid)