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authorDamjan Marion <damarion@cisco.com>2021-05-14 14:36:23 +0200
committerAndrew Yourtchenko <ayourtch@gmail.com>2021-05-17 11:02:08 +0000
commit3d2c6743f4e0958df3189c9e8e08e7d56f1e0df7 (patch)
tree7f8bc41cf422fbb251133346e69dc8355ebce3e2 /src
parent637c97c7d05813ee2cd60c07746ae6205fbb4202 (diff)
memif: remove barriers
Type: improvement Change-Id: Idef30aee80b654ce424b6f1f1f730574ca68874c Signed-off-by: Damjan Marion <damarion@cisco.com>
Diffstat (limited to 'src')
-rw-r--r--src/plugins/memif/device.c36
-rw-r--r--src/plugins/memif/node.c19
2 files changed, 33 insertions, 22 deletions
diff --git a/src/plugins/memif/device.c b/src/plugins/memif/device.c
index d6d4ae3780b..befc0b50eab 100644
--- a/src/plugins/memif/device.c
+++ b/src/plugins/memif/device.c
@@ -112,6 +112,7 @@ memif_interface_tx_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
memif_copy_op_t *co;
memif_region_index_t last_region = ~0;
void *last_region_shm = 0;
+ u16 head, tail;
ring = mq->ring;
ring_size = 1 << mq->log2_ring_size;
@@ -119,14 +120,20 @@ memif_interface_tx_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
retry:
- free_slots = ring->tail - mq->last_tail;
- mq->last_tail += free_slots;
- slot = (type == MEMIF_RING_S2M) ? ring->head : ring->tail;
-
if (type == MEMIF_RING_S2M)
- free_slots = ring_size - ring->head + mq->last_tail;
+ {
+ slot = head = ring->head;
+ tail = __atomic_load_n (&ring->tail, __ATOMIC_ACQUIRE);
+ mq->last_tail += tail - mq->last_tail;
+ free_slots = ring_size - head + mq->last_tail;
+ }
else
- free_slots = ring->head - ring->tail;
+ {
+ slot = tail = ring->tail;
+ head = __atomic_load_n (&ring->head, __ATOMIC_ACQUIRE);
+ mq->last_tail += tail - mq->last_tail;
+ free_slots = head - tail;
+ }
while (n_left && free_slots)
{
@@ -263,11 +270,10 @@ no_free_slots:
vec_reset_length (ptd->copy_ops);
vec_reset_length (ptd->buffers);
- CLIB_MEMORY_STORE_BARRIER ();
if (type == MEMIF_RING_S2M)
- ring->head = slot;
+ __atomic_store_n (&ring->head, slot, __ATOMIC_RELEASE);
else
- ring->tail = slot;
+ __atomic_store_n (&ring->tail, slot, __ATOMIC_RELEASE);
if (n_left && n_retries--)
goto retry;
@@ -306,9 +312,13 @@ memif_interface_tx_zc_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
u16 mask = ring_size - 1;
int n_retries = 5;
vlib_buffer_t *b0;
+ u16 head, tail;
retry:
- n_free = ring->tail - mq->last_tail;
+ slot = tail = __atomic_load_n (&ring->tail, __ATOMIC_ACQUIRE);
+ head = ring->head;
+
+ n_free = tail - mq->last_tail;
if (n_free >= 16)
{
vlib_buffer_free_from_ring_no_next (vm, mq->buffers,
@@ -317,8 +327,7 @@ retry:
mq->last_tail += n_free;
}
- slot = ring->head;
- free_slots = ring_size - ring->head + mq->last_tail;
+ free_slots = ring_size - head + mq->last_tail;
while (n_left && free_slots)
{
@@ -375,8 +384,7 @@ retry:
}
no_free_slots:
- CLIB_MEMORY_STORE_BARRIER ();
- ring->head = slot;
+ __atomic_store_n (&ring->head, slot, __ATOMIC_RELEASE);
if (n_left && n_retries--)
goto retry;
diff --git a/src/plugins/memif/node.c b/src/plugins/memif/node.c
index 7c4de8b8564..24e8522636e 100644
--- a/src/plugins/memif/node.c
+++ b/src/plugins/memif/node.c
@@ -212,7 +212,12 @@ memif_device_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
/* for S2M rings, we are consumers of packet buffers, and for M2S rings we
are producers of empty buffers */
cur_slot = (type == MEMIF_RING_S2M) ? mq->last_head : mq->last_tail;
- last_slot = (type == MEMIF_RING_S2M) ? ring->head : ring->tail;
+
+ if (type == MEMIF_RING_S2M)
+ last_slot = __atomic_load_n (&ring->head, __ATOMIC_ACQUIRE);
+ else
+ last_slot = __atomic_load_n (&ring->tail, __ATOMIC_ACQUIRE);
+
if (cur_slot == last_slot)
goto refill;
n_slots = last_slot - cur_slot;
@@ -336,8 +341,8 @@ memif_device_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
/* release slots from the ring */
if (type == MEMIF_RING_S2M)
{
- CLIB_MEMORY_STORE_BARRIER ();
- ring->tail = mq->last_head = cur_slot;
+ __atomic_store_n (&ring->tail, cur_slot, __ATOMIC_RELEASE);
+ mq->last_head = cur_slot;
}
else
{
@@ -537,8 +542,7 @@ refill:
d->length = mif->run.buffer_size;
}
- CLIB_MEMORY_STORE_BARRIER ();
- ring->head = head;
+ __atomic_store_n (&ring->head, head, __ATOMIC_RELEASE);
}
return n_rx_packets;
@@ -583,7 +587,7 @@ memif_device_input_zc_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
buffer_length = vlib_buffer_get_default_data_size (vm) - start_offset;
cur_slot = mq->last_tail;
- last_slot = ring->tail;
+ last_slot = __atomic_load_n (&ring->tail, __ATOMIC_ACQUIRE);
if (cur_slot == last_slot)
goto refill;
n_slots = last_slot - cur_slot;
@@ -867,8 +871,7 @@ refill:
n_alloc -= 1;
}
- CLIB_MEMORY_STORE_BARRIER ();
- ring->head = head;
+ __atomic_store_n (&ring->head, head, __ATOMIC_RELEASE);
done:
return n_rx_packets;