diff options
Diffstat (limited to 'src/vnet/devices/virtio')
| -rw-r--r-- | src/vnet/devices/virtio/device.c | 103 | ||||
| -rw-r--r-- | src/vnet/devices/virtio/pci.c | 1 | ||||
| -rw-r--r-- | src/vnet/devices/virtio/virtio.c | 5 | ||||
| -rw-r--r-- | src/vnet/devices/virtio/virtio.h | 1 |
4 files changed, 102 insertions, 8 deletions
diff --git a/src/vnet/devices/virtio/device.c b/src/vnet/devices/virtio/device.c index ecc8b8c1aa7..588c84b7275 100644 --- a/src/vnet/devices/virtio/device.c +++ b/src/vnet/devices/virtio/device.c @@ -33,7 +33,8 @@ _(NO_FREE_SLOTS, "no free tx slots") \ _(TRUNC_PACKET, "packet > buffer size -- truncated in tx ring") \ _(PENDING_MSGS, "pending msgs in tx ring") \ -_(NO_TX_QUEUES, "no tx queues") +_(NO_TX_QUEUES, "no tx queues") \ +_(OUT_OF_ORDER, "out-of-order buffers in used ring") typedef enum { @@ -73,13 +74,31 @@ format_virtio_tx_trace (u8 * s, va_list * args) } static_always_inline void -virtio_free_used_device_desc (vlib_main_t * vm, virtio_vring_t * vring) +virtio_memset_ring_u32 (u32 * ring, u32 start, u32 ring_size, u32 n_buffers) +{ + ASSERT (n_buffers <= ring_size); + + if (PREDICT_TRUE (start + n_buffers <= ring_size)) + { + clib_memset_u32 (ring + start, ~0, n_buffers); + } + else + { + clib_memset_u32 (ring + start, ~0, ring_size - start); + clib_memset_u32 (ring, ~0, n_buffers - (ring_size - start)); + } +} + +static_always_inline void +virtio_free_used_device_desc (vlib_main_t * vm, virtio_vring_t * vring, + uword node_index) { u16 used = vring->desc_in_use; u16 sz = vring->size; u16 mask = sz - 1; u16 last = vring->last_used_idx; u16 n_left = vring->used->idx - last; + u16 out_of_order_count = 0; if (n_left == 0) return; @@ -90,7 +109,7 @@ virtio_free_used_device_desc (vlib_main_t * vm, virtio_vring_t * vring) u16 slot, n_buffers; slot = n_buffers = e->id; - while (e->id == n_buffers) + while (e->id == (n_buffers & mask)) { n_left--; last++; @@ -101,18 +120,29 @@ virtio_free_used_device_desc (vlib_main_t * vm, virtio_vring_t * vring) } vlib_buffer_free_from_ring (vm, vring->buffers, slot, sz, (n_buffers - slot)); + virtio_memset_ring_u32 (vring->buffers, slot, sz, (n_buffers - slot)); used -= (n_buffers - slot); if (n_left > 0) { - slot = e->id; - - vlib_buffer_free (vm, &vring->buffers[slot], 1); + vlib_buffer_free (vm, &vring->buffers[e->id], 1); + vring->buffers[e->id] = ~0; used--; last++; n_left--; + out_of_order_count++; + vring->flags |= VRING_TX_OUT_OF_ORDER; } } + + /* + * Some vhost-backends give buffers back in out-of-order fashion in used ring. + * It impacts the overall virtio-performance. + */ + if (out_of_order_count) + vlib_error_count (vm, node_index, VIRTIO_TX_ERROR_OUT_OF_ORDER, + out_of_order_count); + vring->desc_in_use = used; vring->last_used_idx = last; } @@ -302,6 +332,42 @@ add_buffer_to_slot (vlib_main_t * vm, virtio_if_t * vif, return n_added; } +static_always_inline void +virtio_find_free_desc (virtio_vring_t * vring, u16 size, u16 mask, + u16 req, u16 next, u32 * first_free_desc_index, + u16 * free_desc_count) +{ + u16 start = 0; + /* next is used as hint: from where to start looking */ + for (u16 i = 0; i < size; i++, next++) + { + if (vring->buffers[next & mask] == ~0) + { + if (*first_free_desc_index == ~0) + { + *first_free_desc_index = (next & mask); + start = i; + (*free_desc_count)++; + req--; + if (req == 0) + break; + } + else + { + if (start + *free_desc_count == i) + { + (*free_desc_count)++; + req--; + if (req == 0) + break; + } + else + break; + } + } + } +} + static_always_inline uword virtio_interface_tx_inline (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame, virtio_if_t * vif, @@ -314,6 +380,7 @@ virtio_interface_tx_inline (vlib_main_t * vm, vlib_node_runtime_t * node, u16 used, next, avail; u16 sz = vring->size; u16 mask = sz - 1; + u16 retry_count = 2; u32 *buffers = vlib_frame_vector_args (frame); clib_spinlock_lock_if_init (&vring->lockp); @@ -322,14 +389,30 @@ virtio_interface_tx_inline (vlib_main_t * vm, vlib_node_runtime_t * node, (vring->last_kick_avail_idx != vring->avail->idx)) virtio_kick (vm, vring, vif); +retry: /* free consumed buffers */ - virtio_free_used_device_desc (vm, vring); + virtio_free_used_device_desc (vm, vring, node->node_index); used = vring->desc_in_use; next = vring->desc_next; avail = vring->avail->idx; - while (n_left && used < sz) + u16 free_desc_count = 0; + + if (PREDICT_FALSE (vring->flags & VRING_TX_OUT_OF_ORDER)) + { + u32 first_free_desc_index = ~0; + + virtio_find_free_desc (vring, sz, mask, n_left, next, + &first_free_desc_index, &free_desc_count); + + if (free_desc_count) + next = first_free_desc_index; + } + else + free_desc_count = sz - used; + + while (n_left && free_desc_count) { u16 n_added = 0; n_added = @@ -342,6 +425,7 @@ virtio_interface_tx_inline (vlib_main_t * vm, vlib_node_runtime_t * node, used += n_added; buffers++; n_left--; + free_desc_count--; } if (n_left != frame->n_vectors) @@ -356,6 +440,9 @@ virtio_interface_tx_inline (vlib_main_t * vm, vlib_node_runtime_t * node, if (n_left) { + if (retry_count--) + goto retry; + vlib_error_count (vm, node->node_index, VIRTIO_TX_ERROR_NO_FREE_SLOTS, n_left); vlib_buffer_free (vm, buffers, n_left); diff --git a/src/vnet/devices/virtio/pci.c b/src/vnet/devices/virtio/pci.c index c956e7b75fa..65dab0ae769 100644 --- a/src/vnet/devices/virtio/pci.c +++ b/src/vnet/devices/virtio/pci.c @@ -823,6 +823,7 @@ virtio_pci_vring_init (vlib_main_t * vm, virtio_if_t * vif, u16 queue_num) { virtio_log_debug (vif, "tx-queue: number %u, size %u", queue_num, queue_size); + clib_memset_u32 (vring->buffers, ~0, queue_size); } else { diff --git a/src/vnet/devices/virtio/virtio.c b/src/vnet/devices/virtio/virtio.c index 2b353a6a53d..d78c9114e5c 100644 --- a/src/vnet/devices/virtio/virtio.c +++ b/src/vnet/devices/virtio/virtio.c @@ -113,6 +113,11 @@ virtio_vring_init (vlib_main_t * vm, virtio_if_t * vif, u16 idx, u16 sz) ASSERT (vring->buffers == 0); vec_validate_aligned (vring->buffers, sz, CLIB_CACHE_LINE_BYTES); + if (idx & 1) + { + clib_memset_u32 (vring->buffers, ~0, sz); + } + vring->size = sz; vring->call_fd = eventfd (0, EFD_NONBLOCK | EFD_CLOEXEC); vring->kick_fd = eventfd (0, EFD_NONBLOCK | EFD_CLOEXEC); diff --git a/src/vnet/devices/virtio/virtio.h b/src/vnet/devices/virtio/virtio.h index 4b8662699da..e28922bf654 100644 --- a/src/vnet/devices/virtio/virtio.h +++ b/src/vnet/devices/virtio/virtio.h @@ -112,6 +112,7 @@ typedef struct u8 buffer_pool_index; u16 size; u16 queue_id; +#define VRING_TX_OUT_OF_ORDER 1 u16 flags; u32 call_file_index; u32 *buffers; |