libmemif: perf optimization

Change-Id: Ie3bd75e0e98c7ecb4c66dba701131363e5ec89a2
Signed-off-by: Jakub Grajciar <Jakub.Grajciar@pantheon.tech>

diff --git a/extras/libmemif/src/main.c b/extras/libmemif/src/main.c
index b1176c6..39c18f2 100644 (file)
--- a/extras/libmemif/src/main.c
+++ b/extras/libmemif/src/main.c
@@ -1388,43 +1388,35 @@ memif_buffer_alloc (memif_conn_handle_t conn, uint16_t qid,
   memif_queue_t *mq = &c->tx_queues[qid];
   memif_ring_t *ring = mq->ring;
   memif_buffer_t *b0, *b1;
-  uint8_t chain_buf0, chain_buf1;
+  uint8_t chain_buf = 1;
   uint16_t mask = (1 << mq->log2_ring_size) - 1;
   uint16_t s0, s1, ns;
   *count_out = 0;
   int i, err = MEMIF_ERR_SUCCESS;      /* 0 */
 
-  if (ring->tail != ring->head)
-    {
-      if (ring->head > ring->tail)
-       ns = (1 << mq->log2_ring_size) - ring->head + ring->tail;
-      else
-       ns = ring->tail - ring->head;
-    }
+  if (ring->tail > ring->head)
+    ns = ring->tail - ring->head;
   else
-    ns = (1 << mq->log2_ring_size);
+    ns = (1 << mq->log2_ring_size) - ring->head + ring->tail;
 
   /* (head == tail) ? receive function will asume that no packets are available */
   ns -= 1;
 
+  if (size > ring->desc[0].buffer_length)
+    {
+      chain_buf = size / ring->desc[s0].buffer_length;
+      if (((size % ring->desc[s0].buffer_length) != 0) || (size == 0))
+       chain_buf++;
+    }
+
   while (count && ns)
     {
       while ((count > 2) && (ns > 2))
        {
          s0 = (ring->head + mq->alloc_bufs) & mask;
-         chain_buf0 = size / ring->desc[s0].buffer_length;
-         if (((size % ring->desc[s0].buffer_length) != 0) || (size == 0))
-           chain_buf0++;
+         s1 = (ring->head + mq->alloc_bufs + chain_buf) & mask;
 
-         if (chain_buf0 > ns)
-           break;
-
-         s1 = (ring->head + mq->alloc_bufs + chain_buf0) & mask;
-         chain_buf1 = size / ring->desc[s1].buffer_length;
-         if (((size % ring->desc[s1].buffer_length) != 0) || (size == 0))
-           chain_buf1++;
-
-         if ((chain_buf0 + chain_buf1) > ns)
+         if ((2 * chain_buf) > ns)
            break;
 
          b0 = (bufs + *count_out);
@@ -1434,64 +1426,49 @@ memif_buffer_alloc (memif_conn_handle_t conn, uint16_t qid,
          b1->desc_index = s1;
          ring->desc[s0].flags = 0;
          ring->desc[s1].flags = 0;
-         b0->buffer_len = ring->desc[s0].buffer_length * chain_buf0;
-         b1->buffer_len = ring->desc[s1].buffer_length * chain_buf1;
+         b0->buffer_len = ring->desc[s0].buffer_length * chain_buf;
+         b1->buffer_len = ring->desc[s1].buffer_length * chain_buf;
          /* TODO: support multiple regions -> ring descriptor contains region index */
          b0->data = c->regions->shm + ring->desc[s0].offset;
          b1->data = c->regions->shm + ring->desc[s1].offset;
 
-         for (i = 0; i < (memif_min (chain_buf0, chain_buf1) - 1); i++)
+         for (i = 0; i < (chain_buf - 1); i++)
            {
              ring->desc[(s0 + i) & mask].flags |= MEMIF_DESC_FLAG_NEXT;
              ring->desc[(s1 + i) & mask].flags |= MEMIF_DESC_FLAG_NEXT;
              DBG ("allocating chained buffers");
            }
 
-         if (chain_buf0 > chain_buf1)
-           {
-             for (; i < (chain_buf0 - 1); i++)
-               ring->desc[(s0 + i) & mask].flags |= MEMIF_DESC_FLAG_NEXT;
-           }
-         else
-           {
-             for (; i < (chain_buf1 - 1); i++)
-               ring->desc[(s1 + i) & mask].flags |= MEMIF_DESC_FLAG_NEXT;
-           }
-
-         mq->alloc_bufs += chain_buf0 + chain_buf1;
+         mq->alloc_bufs += 2 * chain_buf;
 
          DBG ("allocated ring slots %u, %u", s0, s1);
          count -= 2;
-         ns -= chain_buf0 + chain_buf1;
+         ns -= (2 * chain_buf);
          *count_out += 2;
        }
       s0 = (ring->head + mq->alloc_bufs) & mask;
 
       b0 = (bufs + *count_out);
 
-      chain_buf0 = size / ring->desc[s0].buffer_length;
-      if (((size % ring->desc[s0].buffer_length) != 0) || (size == 0))
-       chain_buf0++;
-
-      if (chain_buf0 > ns)
+      if (chain_buf > ns)
        break;
 
       b0->desc_index = s0;
       ring->desc[s0].flags = 0;
-      b0->buffer_len = ring->desc[s0].buffer_length * chain_buf0;
+      b0->buffer_len = ring->desc[s0].buffer_length * chain_buf;
       b0->data = c->regions->shm + ring->desc[s0].offset;
 
-      for (i = 0; i < (chain_buf0 - 1); i++)
+      for (i = 0; i < (chain_buf - 1); i++)
        {
          ring->desc[(s0 + i) & mask].flags |= MEMIF_DESC_FLAG_NEXT;
          DBG ("allocating chained buffers");
        }
 
-      mq->alloc_bufs += chain_buf0;
+      mq->alloc_bufs += chain_buf;
 
       DBG ("allocated ring slot %u", s0);
       count--;
-      ns -= chain_buf0;
+      ns -= chain_buf;
       *count_out += 1;
     }
 
@@ -1819,7 +1796,9 @@ memif_rx_burst (memif_conn_handle_t conn, uint16_t qid,
   memif_buffer_t *b0, *b1;
   uint16_t curr_buf = 0;
   *rx = 0;
+#ifdef MEMIF_DBG_SHM
   int i;
+#endif /* MEMIF_DBG_SHM */
 
   uint64_t b;
   ssize_t r = read (mq->int_fd, &b, sizeof (b));
@@ -1836,21 +1815,17 @@ memif_rx_burst (memif_conn_handle_t conn, uint16_t qid,
 
   while (ns && count)
     {
-      DBG ("ns: %u, count: %u", ns, count);
       while ((ns > 2) && (count > 2))
        {
          b0 = (bufs + curr_buf);
          b1 = (bufs + curr_buf + 1);
 
          b0->desc_index = mq->last_head;
-         i = 0;
-         b0->data_len = 0;
-         b0->buffer_len = 0;
-
          b0->data = memif_get_buffer (conn, ring, mq->last_head);
-         b0->data_len += ring->desc[mq->last_head].length;
-         b0->buffer_len += ring->desc[mq->last_head].buffer_length;
+         b0->data_len = ring->desc[mq->last_head].length;
+         b0->buffer_len = ring->desc[mq->last_head].buffer_length;
 #ifdef MEMIF_DBG_SHM
+         i = 0;
          print_bytes (b0->data +
                       ring->desc[b0->desc_index].buffer_length * i++,
                       ring->desc[b0->desc_index].buffer_length, DBG_TX_BUF);
@@ -1875,14 +1850,11 @@ memif_rx_burst (memif_conn_handle_t conn, uint16_t qid,
          mq->last_head = (mq->last_head + 1) & mask;
 
          b1->desc_index = mq->last_head;
-         i = 0;
-         b1->data_len = 0;
-         b1->buffer_len = 0;
-
          b1->data = memif_get_buffer (conn, ring, mq->last_head);
-         b1->data_len += ring->desc[mq->last_head].length;
-         b1->buffer_len += ring->desc[mq->last_head].buffer_length;
+         b1->data_len = ring->desc[mq->last_head].length;
+         b1->buffer_len = ring->desc[mq->last_head].buffer_length;
 #ifdef MEMIF_DBG_SHM
+         i = 0;
          print_bytes (b1->data +
                       ring->desc[b1->desc_index].buffer_length * i++,
                       ring->desc[b1->desc_index].buffer_length, DBG_TX_BUF);
@@ -1912,14 +1884,11 @@ memif_rx_burst (memif_conn_handle_t conn, uint16_t qid,
       b0 = (bufs + curr_buf);
 
       b0->desc_index = mq->last_head;
-      i = 0;
-      b0->data_len = 0;
-      b0->buffer_len = 0;
-
       b0->data = memif_get_buffer (conn, ring, mq->last_head);
-      b0->data_len += ring->desc[mq->last_head].length;
-      b0->buffer_len += ring->desc[mq->last_head].buffer_length;
+      b0->data_len = ring->desc[mq->last_head].length;
+      b0->buffer_len = ring->desc[mq->last_head].buffer_length;
 #ifdef MEMIF_DBG_SHM
+         i = 0;
       print_bytes (b0->data +
                   ring->desc[b0->desc_index].buffer_length * i++,
                   ring->desc[b0->desc_index].buffer_length, DBG_TX_BUF);