avf: avoid placeholder buffer alloc in datapath
Type: improvement
Change-Id: I0ad0fa42f056b5797ba71d6972a44273c13bb97e
Signed-off-by: Damjan Marion <damarion@cisco.com>
diff --git a/src/plugins/avf/avf.h b/src/plugins/avf/avf.h
index f7ea407..ea931dc 100644
--- a/src/plugins/avf/avf.h
+++ b/src/plugins/avf/avf.h
@@ -182,7 +182,7 @@
volatile u32 *qtx_tail;
u16 next;
u16 size;
- u32 ctx_desc_placeholder_bi;
+ u32 *ph_bufs;
clib_spinlock_t lock;
avf_tx_desc_t *descs;
u32 *bufs;
diff --git a/src/plugins/avf/device.c b/src/plugins/avf/device.c
index e0c3c99..70ea446 100644
--- a/src/plugins/avf/device.c
+++ b/src/plugins/avf/device.c
@@ -295,6 +295,7 @@
{
clib_error_t *err;
avf_txq_t *txq;
+ u16 n;
u8 bpi = vlib_buffer_pool_get_default_for_numa (vm,
ad->numa_node);
@@ -313,11 +314,15 @@
txq->size = txq_size;
txq->next = 0;
- /* Prepare a placeholder buffer to maintain a 1-1
- relationship between bufs and descs when a context
- descriptor is added in descs */
- if (!vlib_buffer_alloc_from_pool
- (vm, &txq->ctx_desc_placeholder_bi, 1, bpi))
+ /* Prepare a placeholder buffer(s) to maintain a 1-1 relationship between
+ * bufs and descs when a context descriptor is added in descs. Worst case
+ * every second descriptor is context descriptor and due to b->ref_count
+ * being u8 we need one for each block of 510 descriptors */
+
+ n = (txq->size / 510) + 1;
+ vec_validate_aligned (txq->ph_bufs, n, CLIB_CACHE_LINE_BYTES);
+
+ if (!vlib_buffer_alloc_from_pool (vm, txq->ph_bufs, n, bpi))
return clib_error_return (0, "buffer allocation error");
txq->descs = vlib_physmem_alloc_aligned_on_numa (vm, txq->size *
@@ -1518,7 +1523,8 @@
txq->n_enqueued);
}
/* Free the placeholder buffer */
- vlib_buffer_free_one(vm, txq->ctx_desc_placeholder_bi);
+ vlib_buffer_free (vm, txq->ph_bufs, vec_len (txq->ph_bufs));
+ vec_free (txq->ph_bufs);
vec_free (txq->bufs);
clib_ring_free (txq->rs_slots);
vec_free (txq->tmp_bufs);
diff --git a/src/plugins/avf/output.c b/src/plugins/avf/output.c
index 3f361f0..8c932cc 100644
--- a/src/plugins/avf/output.c
+++ b/src/plugins/avf/output.c
@@ -129,28 +129,19 @@
return flags;
}
-static_always_inline int
-avf_tx_fill_ctx_desc (vlib_main_t * vm, avf_txq_t * txq, avf_tx_desc_t * d,
- vlib_buffer_t * b)
+static_always_inline u32
+avf_tx_fill_ctx_desc (vlib_main_t *vm, avf_txq_t *txq, avf_tx_desc_t *d,
+ vlib_buffer_t *b)
{
- vlib_buffer_t *ctx_ph = vlib_get_buffer (vm, txq->ctx_desc_placeholder_bi);
+ vlib_buffer_t *ctx_ph;
+ u32 *bi = txq->ph_bufs;
+
+next:
+ ctx_ph = vlib_get_buffer (vm, bi[0]);
if (PREDICT_FALSE (ctx_ph->ref_count == 255))
{
- /* We need a new placeholder buffer */
- u32 new_bi;
- u8 bpi = vlib_buffer_pool_get_default_for_numa (vm, vm->numa_node);
- if (PREDICT_TRUE
- (vlib_buffer_alloc_from_pool (vm, &new_bi, 1, bpi) == 1))
- {
- /* Remove our own reference on the current placeholder buffer */
- ctx_ph->ref_count--;
- /* Replace with the new placeholder buffer */
- txq->ctx_desc_placeholder_bi = new_bi;
- ctx_ph = vlib_get_buffer (vm, new_bi);
- }
- else
- /* Impossible to enqueue a ctx descriptor, fail */
- return 1;
+ bi++;
+ goto next;
}
/* Acquire a reference on the placeholder buffer */
@@ -163,7 +154,7 @@
d[0].qword[1] = AVF_TXD_DTYP_CTX | AVF_TXD_CTX_CMD_TSO
| AVF_TXD_CTX_SEG_MSS (vnet_buffer2 (b)->gso_size) |
AVF_TXD_CTX_SEG_TLEN (tlen);
- return 0;
+ return bi[0];
}
static_always_inline void
@@ -334,11 +325,8 @@
/* Enqueue a context descriptor if needed */
if (PREDICT_FALSE (is_tso))
{
- if (avf_tx_fill_ctx_desc (vm, txq, d, b[0]))
- /* Failure to acquire ref on ctx placeholder */
- break;
tb[1] = tb[0];
- tb[0] = txq->ctx_desc_placeholder_bi;
+ tb[0] = avf_tx_fill_ctx_desc (vm, txq, d, b[0]);
n_desc += 1;
n_desc_left -= 1;
d += 1;