* [dpdk-dev] [PATCH 1/2] vhost: unify Rx mergeable and non-mergeable paths
2018-05-28 16:23 [dpdk-dev] [PATCH 0/2] Vhost: unitfy receive paths Maxime Coquelin
@ 2018-05-28 16:23 ` Maxime Coquelin
2018-05-28 18:33 ` Maxime Coquelin
2018-05-28 16:23 ` [dpdk-dev] [PATCH 2/2] vhost: improve batched copies performance Maxime Coquelin
1 sibling, 1 reply; 4+ messages in thread
From: Maxime Coquelin @ 2018-05-28 16:23 UTC (permalink / raw)
To: dev, tiwei.bie, zhihong.wang; +Cc: Maxime Coquelin
This patch reworks the vhost enqueue path so that a single
code path is used for both Rx mergeable or non-mergeable cases.
Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
lib/librte_vhost/virtio_net.c | 337 +++---------------------------------------
1 file changed, 18 insertions(+), 319 deletions(-)
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 76ec5f089..c5237f853 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -25,6 +25,12 @@
#define MAX_BATCH_LEN 256
+static __rte_always_inline bool
+rxvq_is_mergeable(struct virtio_net *dev)
+{
+ return dev->features && (1ULL << VIRTIO_NET_F_MRG_RXBUF);
+}
+
static bool
is_valid_virt_queue_idx(uint32_t idx, int is_tx, uint32_t nr_vring)
{
@@ -154,7 +160,7 @@ do_data_copy_dequeue(struct vhost_virtqueue *vq)
(var) = (val); \
} while (0)
-static void
+static __rte_always_inline void
virtio_enqueue_offload(struct rte_mbuf *m_buf, struct virtio_net_hdr *net_hdr)
{
uint64_t csum_l4 = m_buf->ol_flags & PKT_TX_L4_MASK;
@@ -215,317 +221,6 @@ virtio_enqueue_offload(struct rte_mbuf *m_buf, struct virtio_net_hdr *net_hdr)
}
}
-static __rte_always_inline int
-copy_mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
- struct vring_desc *descs, struct rte_mbuf *m,
- uint16_t desc_idx, uint32_t size)
-{
- uint32_t desc_avail, desc_offset;
- uint32_t mbuf_avail, mbuf_offset;
- uint32_t cpy_len;
- uint64_t desc_chunck_len;
- struct vring_desc *desc;
- uint64_t desc_addr, desc_gaddr;
- /* A counter to avoid desc dead loop chain */
- uint16_t nr_desc = 1;
- struct batch_copy_elem *batch_copy = vq->batch_copy_elems;
- uint16_t copy_nb = vq->batch_copy_nb_elems;
- int error = 0;
-
- desc = &descs[desc_idx];
- desc_chunck_len = desc->len;
- desc_gaddr = desc->addr;
- desc_addr = vhost_iova_to_vva(dev, vq, desc_gaddr,
- &desc_chunck_len, VHOST_ACCESS_RW);
- /*
- * Checking of 'desc_addr' placed outside of 'unlikely' macro to avoid
- * performance issue with some versions of gcc (4.8.4 and 5.3.0) which
- * otherwise stores offset on the stack instead of in a register.
- */
- if (unlikely(desc->len < dev->vhost_hlen) || !desc_addr) {
- error = -1;
- goto out;
- }
-
- rte_prefetch0((void *)(uintptr_t)desc_addr);
-
- if (likely(desc_chunck_len >= dev->vhost_hlen)) {
- virtio_enqueue_offload(m,
- (struct virtio_net_hdr *)(uintptr_t)desc_addr);
- PRINT_PACKET(dev, (uintptr_t)desc_addr, dev->vhost_hlen, 0);
- vhost_log_cache_write(dev, vq, desc_gaddr, dev->vhost_hlen);
- } else {
- struct virtio_net_hdr vnet_hdr;
- uint64_t remain = dev->vhost_hlen;
- uint64_t len;
- uint64_t src = (uint64_t)(uintptr_t)&vnet_hdr, dst;
- uint64_t guest_addr = desc_gaddr;
-
- virtio_enqueue_offload(m, &vnet_hdr);
-
- while (remain) {
- len = remain;
- dst = vhost_iova_to_vva(dev, vq, guest_addr,
- &len, VHOST_ACCESS_RW);
- if (unlikely(!dst || !len)) {
- error = -1;
- goto out;
- }
-
- rte_memcpy((void *)(uintptr_t)dst,
- (void *)(uintptr_t)src, len);
-
- PRINT_PACKET(dev, (uintptr_t)dst, (uint32_t)len, 0);
- vhost_log_cache_write(dev, vq, guest_addr, len);
- remain -= len;
- guest_addr += len;
- src += len;
- }
- }
-
- desc_avail = desc->len - dev->vhost_hlen;
- if (unlikely(desc_chunck_len < dev->vhost_hlen)) {
- desc_chunck_len = desc_avail;
- desc_gaddr = desc->addr + dev->vhost_hlen;
- desc_addr = vhost_iova_to_vva(dev,
- vq, desc_gaddr,
- &desc_chunck_len,
- VHOST_ACCESS_RW);
- if (unlikely(!desc_addr)) {
- error = -1;
- goto out;
- }
-
- desc_offset = 0;
- } else {
- desc_offset = dev->vhost_hlen;
- desc_chunck_len -= dev->vhost_hlen;
- }
-
- mbuf_avail = rte_pktmbuf_data_len(m);
- mbuf_offset = 0;
- while (mbuf_avail != 0 || m->next != NULL) {
- /* done with current mbuf, fetch next */
- if (mbuf_avail == 0) {
- m = m->next;
-
- mbuf_offset = 0;
- mbuf_avail = rte_pktmbuf_data_len(m);
- }
-
- /* done with current desc buf, fetch next */
- if (desc_avail == 0) {
- if ((desc->flags & VRING_DESC_F_NEXT) == 0) {
- /* Room in vring buffer is not enough */
- error = -1;
- goto out;
- }
- if (unlikely(desc->next >= size || ++nr_desc > size)) {
- error = -1;
- goto out;
- }
-
- desc = &descs[desc->next];
- desc_chunck_len = desc->len;
- desc_gaddr = desc->addr;
- desc_addr = vhost_iova_to_vva(dev, vq, desc_gaddr,
- &desc_chunck_len,
- VHOST_ACCESS_RW);
- if (unlikely(!desc_addr)) {
- error = -1;
- goto out;
- }
-
- desc_offset = 0;
- desc_avail = desc->len;
- } else if (unlikely(desc_chunck_len == 0)) {
- desc_chunck_len = desc_avail;
- desc_gaddr += desc_offset;
- desc_addr = vhost_iova_to_vva(dev,
- vq, desc_gaddr,
- &desc_chunck_len, VHOST_ACCESS_RW);
- if (unlikely(!desc_addr)) {
- error = -1;
- goto out;
- }
- desc_offset = 0;
- }
-
- cpy_len = RTE_MIN(desc_chunck_len, mbuf_avail);
- if (likely(cpy_len > MAX_BATCH_LEN || copy_nb >= vq->size)) {
- rte_memcpy((void *)((uintptr_t)(desc_addr +
- desc_offset)),
- rte_pktmbuf_mtod_offset(m, void *, mbuf_offset),
- cpy_len);
- vhost_log_cache_write(dev, vq, desc_gaddr + desc_offset,
- cpy_len);
- PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset),
- cpy_len, 0);
- } else {
- batch_copy[copy_nb].dst =
- (void *)((uintptr_t)(desc_addr + desc_offset));
- batch_copy[copy_nb].src =
- rte_pktmbuf_mtod_offset(m, void *, mbuf_offset);
- batch_copy[copy_nb].log_addr = desc_gaddr + desc_offset;
- batch_copy[copy_nb].len = cpy_len;
- copy_nb++;
- }
-
- mbuf_avail -= cpy_len;
- mbuf_offset += cpy_len;
- desc_avail -= cpy_len;
- desc_offset += cpy_len;
- desc_chunck_len -= cpy_len;
- }
-
-out:
- vq->batch_copy_nb_elems = copy_nb;
-
- return error;
-}
-
-/**
- * This function adds buffers to the virtio devices RX virtqueue. Buffers can
- * be received from the physical port or from another virtio device. A packet
- * count is returned to indicate the number of packets that are successfully
- * added to the RX queue. This function works when the mbuf is scattered, but
- * it doesn't support the mergeable feature.
- */
-static __rte_always_inline uint32_t
-virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
- struct rte_mbuf **pkts, uint32_t count)
-{
- struct vhost_virtqueue *vq;
- uint16_t avail_idx, free_entries, start_idx;
- uint16_t desc_indexes[MAX_PKT_BURST];
- struct vring_desc *descs;
- uint16_t used_idx;
- uint32_t i, sz;
-
- VHOST_LOG_DEBUG(VHOST_DATA, "(%d) %s\n", dev->vid, __func__);
- if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->nr_vring))) {
- RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid virtqueue idx %d.\n",
- dev->vid, __func__, queue_id);
- return 0;
- }
-
- vq = dev->virtqueue[queue_id];
-
- rte_spinlock_lock(&vq->access_lock);
-
- if (unlikely(vq->enabled == 0))
- goto out_access_unlock;
-
- if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
- vhost_user_iotlb_rd_lock(vq);
-
- if (unlikely(vq->access_ok == 0)) {
- if (unlikely(vring_translate(dev, vq) < 0)) {
- count = 0;
- goto out;
- }
- }
-
- avail_idx = *((volatile uint16_t *)&vq->avail->idx);
- start_idx = vq->last_used_idx;
- free_entries = avail_idx - start_idx;
- count = RTE_MIN(count, free_entries);
- count = RTE_MIN(count, (uint32_t)MAX_PKT_BURST);
- if (count == 0)
- goto out;
-
- VHOST_LOG_DEBUG(VHOST_DATA, "(%d) start_idx %d | end_idx %d\n",
- dev->vid, start_idx, start_idx + count);
-
- vq->batch_copy_nb_elems = 0;
-
- /* Retrieve all of the desc indexes first to avoid caching issues. */
- rte_prefetch0(&vq->avail->ring[start_idx & (vq->size - 1)]);
- for (i = 0; i < count; i++) {
- used_idx = (start_idx + i) & (vq->size - 1);
- desc_indexes[i] = vq->avail->ring[used_idx];
- vq->used->ring[used_idx].id = desc_indexes[i];
- vq->used->ring[used_idx].len = pkts[i]->pkt_len +
- dev->vhost_hlen;
- vhost_log_cache_used_vring(dev, vq,
- offsetof(struct vring_used, ring[used_idx]),
- sizeof(vq->used->ring[used_idx]));
- }
-
- rte_prefetch0(&vq->desc[desc_indexes[0]]);
- for (i = 0; i < count; i++) {
- struct vring_desc *idesc = NULL;
- uint16_t desc_idx = desc_indexes[i];
- int err;
-
- if (vq->desc[desc_idx].flags & VRING_DESC_F_INDIRECT) {
- uint64_t dlen = vq->desc[desc_idx].len;
- descs = (struct vring_desc *)(uintptr_t)
- vhost_iova_to_vva(dev,
- vq, vq->desc[desc_idx].addr,
- &dlen, VHOST_ACCESS_RO);
- if (unlikely(!descs)) {
- count = i;
- break;
- }
-
- if (unlikely(dlen < vq->desc[desc_idx].len)) {
- /*
- * The indirect desc table is not contiguous
- * in process VA space, we have to copy it.
- */
- idesc = alloc_copy_ind_table(dev, vq,
- &vq->desc[desc_idx]);
- if (unlikely(!idesc))
- break;
-
- descs = idesc;
- }
-
- desc_idx = 0;
- sz = vq->desc[desc_idx].len / sizeof(*descs);
- } else {
- descs = vq->desc;
- sz = vq->size;
- }
-
- err = copy_mbuf_to_desc(dev, vq, descs, pkts[i], desc_idx, sz);
- if (unlikely(err)) {
- count = i;
- free_ind_table(idesc);
- break;
- }
-
- if (i + 1 < count)
- rte_prefetch0(&vq->desc[desc_indexes[i+1]]);
-
- if (unlikely(!!idesc))
- free_ind_table(idesc);
- }
-
- do_data_copy_enqueue(dev, vq);
-
- rte_smp_wmb();
-
- vhost_log_cache_sync(dev, vq);
-
- *(volatile uint16_t *)&vq->used->idx += count;
- vq->last_used_idx += count;
- vhost_log_used_vring(dev, vq,
- offsetof(struct vring_used, idx),
- sizeof(vq->used->idx));
-
- vhost_vring_call(dev, vq);
-out:
- if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
- vhost_user_iotlb_rd_unlock(vq);
-
-out_access_unlock:
- rte_spinlock_unlock(&vq->access_lock);
-
- return count;
-}
-
static __rte_always_inline int
fill_vec_buf(struct virtio_net *dev, struct vhost_virtqueue *vq,
uint32_t avail_idx, uint32_t *vec_idx,
@@ -602,7 +297,7 @@ reserve_avail_buf_mergeable(struct virtio_net *dev, struct vhost_virtqueue *vq,
{
uint16_t cur_idx;
uint32_t vec_idx = 0;
- uint16_t tries = 0;
+ uint16_t max_tries, tries = 0;
uint16_t head_idx = 0;
uint16_t len = 0;
@@ -610,6 +305,11 @@ reserve_avail_buf_mergeable(struct virtio_net *dev, struct vhost_virtqueue *vq,
*num_buffers = 0;
cur_idx = vq->last_avail_idx;
+ if (rxvq_is_mergeable(dev))
+ max_tries = vq->size;
+ else
+ max_tries = 1;
+
while (size > 0) {
if (unlikely(cur_idx == avail_head))
return -1;
@@ -630,7 +330,7 @@ reserve_avail_buf_mergeable(struct virtio_net *dev, struct vhost_virtqueue *vq,
* can't get enough buf, it means something abnormal
* happened.
*/
- if (unlikely(tries >= vq->size))
+ if (unlikely(tries > max_tries))
return -1;
}
@@ -748,7 +448,9 @@ copy_mbuf_to_desc_mergeable(struct virtio_net *dev, struct vhost_virtqueue *vq,
if (hdr_addr) {
virtio_enqueue_offload(hdr_mbuf, &hdr->hdr);
- ASSIGN_UNLESS_EQUAL(hdr->num_buffers, num_buffers);
+ if (rxvq_is_mergeable(dev))
+ ASSIGN_UNLESS_EQUAL(hdr->num_buffers,
+ num_buffers);
if (unlikely(hdr == &tmp_hdr)) {
uint64_t len;
@@ -923,10 +625,7 @@ rte_vhost_enqueue_burst(int vid, uint16_t queue_id,
return 0;
}
- if (dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF))
- return virtio_dev_merge_rx(dev, queue_id, pkts, count);
- else
- return virtio_dev_rx(dev, queue_id, pkts, count);
+ return virtio_dev_merge_rx(dev, queue_id, pkts, count);
}
static inline bool
--
2.14.3
^ permalink raw reply [flat|nested] 4+ messages in thread* [dpdk-dev] [PATCH 2/2] vhost: improve batched copies performance
2018-05-28 16:23 [dpdk-dev] [PATCH 0/2] Vhost: unitfy receive paths Maxime Coquelin
2018-05-28 16:23 ` [dpdk-dev] [PATCH 1/2] vhost: unify Rx mergeable and non-mergeable paths Maxime Coquelin
@ 2018-05-28 16:23 ` Maxime Coquelin
1 sibling, 0 replies; 4+ messages in thread
From: Maxime Coquelin @ 2018-05-28 16:23 UTC (permalink / raw)
To: dev, tiwei.bie, zhihong.wang; +Cc: Maxime Coquelin
Instead of copying batch_copy_nb_elems into the stack,
this patch uses it directly.
Small performance gain of 3% is seen when running PVP
benchmark.
Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
lib/librte_vhost/virtio_net.c | 29 ++++++++++++++---------------
1 file changed, 14 insertions(+), 15 deletions(-)
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index c5237f853..d29c61ff8 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -352,7 +352,6 @@ copy_mbuf_to_desc_mergeable(struct virtio_net *dev, struct vhost_virtqueue *vq,
struct rte_mbuf *hdr_mbuf;
struct batch_copy_elem *batch_copy = vq->batch_copy_elems;
struct virtio_net_hdr_mrg_rxbuf tmp_hdr, *hdr = NULL;
- uint16_t copy_nb = vq->batch_copy_nb_elems;
int error = 0;
if (unlikely(m == NULL)) {
@@ -493,7 +492,8 @@ copy_mbuf_to_desc_mergeable(struct virtio_net *dev, struct vhost_virtqueue *vq,
cpy_len = RTE_MIN(desc_chunck_len, mbuf_avail);
- if (likely(cpy_len > MAX_BATCH_LEN || copy_nb >= vq->size)) {
+ if (likely(cpy_len > MAX_BATCH_LEN ||
+ vq->batch_copy_nb_elems >= vq->size)) {
rte_memcpy((void *)((uintptr_t)(desc_addr +
desc_offset)),
rte_pktmbuf_mtod_offset(m, void *, mbuf_offset),
@@ -503,13 +503,14 @@ copy_mbuf_to_desc_mergeable(struct virtio_net *dev, struct vhost_virtqueue *vq,
PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset),
cpy_len, 0);
} else {
- batch_copy[copy_nb].dst =
+ batch_copy[vq->batch_copy_nb_elems].dst =
(void *)((uintptr_t)(desc_addr + desc_offset));
- batch_copy[copy_nb].src =
+ batch_copy[vq->batch_copy_nb_elems].src =
rte_pktmbuf_mtod_offset(m, void *, mbuf_offset);
- batch_copy[copy_nb].log_addr = desc_gaddr + desc_offset;
- batch_copy[copy_nb].len = cpy_len;
- copy_nb++;
+ batch_copy[vq->batch_copy_nb_elems].log_addr =
+ desc_gaddr + desc_offset;
+ batch_copy[vq->batch_copy_nb_elems].len = cpy_len;
+ vq->batch_copy_nb_elems++;
}
mbuf_avail -= cpy_len;
@@ -520,7 +521,6 @@ copy_mbuf_to_desc_mergeable(struct virtio_net *dev, struct vhost_virtqueue *vq,
}
out:
- vq->batch_copy_nb_elems = copy_nb;
return error;
}
@@ -766,7 +766,6 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq,
/* A counter to avoid desc dead loop chain */
uint32_t nr_desc = 1;
struct batch_copy_elem *batch_copy = vq->batch_copy_elems;
- uint16_t copy_nb = vq->batch_copy_nb_elems;
int error = 0;
desc = &descs[desc_idx];
@@ -905,7 +904,7 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq,
mbuf_avail = cpy_len;
} else {
if (likely(cpy_len > MAX_BATCH_LEN ||
- copy_nb >= vq->size ||
+ vq->batch_copy_nb_elems >= vq->size ||
(hdr && cur == m) ||
desc->len != desc_chunck_len)) {
rte_memcpy(rte_pktmbuf_mtod_offset(cur, void *,
@@ -914,14 +913,15 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq,
desc_offset)),
cpy_len);
} else {
- batch_copy[copy_nb].dst =
+ batch_copy[vq->batch_copy_nb_elems].dst =
rte_pktmbuf_mtod_offset(cur, void *,
mbuf_offset);
- batch_copy[copy_nb].src =
+ batch_copy[vq->batch_copy_nb_elems].src =
(void *)((uintptr_t)(desc_addr +
desc_offset));
- batch_copy[copy_nb].len = cpy_len;
- copy_nb++;
+ batch_copy[vq->batch_copy_nb_elems].len =
+ cpy_len;
+ vq->batch_copy_nb_elems++;
}
}
@@ -1015,7 +1015,6 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq,
vhost_dequeue_offload(hdr, m);
out:
- vq->batch_copy_nb_elems = copy_nb;
return error;
}
--
2.14.3
^ permalink raw reply [flat|nested] 4+ messages in thread