[dpdk-dev] [RFC PATCH 06/13] add vhost fast enqueue flush function

[Marvin Liu]

Vhost fast enqueue function will flush used ring immediately.
Descriptor's flag is pre-calculated by macro.

Signed-off-by: Marvin Liu <yong....@intel.com>

diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index b8198747e..d084fe364 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -39,6 +39,10 @@
 
 #define VHOST_LOG_CACHE_NR 32
 
+/* Pre-calculated packed ring flags */
+#define VIRTIO_RX_FLAG_PACKED  (0ULL | VRING_DESC_F_AVAIL | VRING_DESC_F_USED 
| VRING_DESC_F_WRITE)
+#define VIRTIO_RX_WRAP_FLAG_PACKED (VRING_DESC_F_WRITE)
+
 /* Used in fast packed ring functions */
 #define PACKED_DESC_PER_CACHELINE (RTE_CACHE_LINE_SIZE / sizeof(struct 
vring_packed_desc))
 
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 96f7a8bec..9eeebe642 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -225,6 +225,63 @@ flush_enqueue_used_packed(struct virtio_net *dev,
        vhost_log_cache_sync(dev, vq);
 }
 
+/* flags are same when flushing used ring in fast path */
+static __rte_always_inline void
+flush_used_fast_packed(struct virtio_net *dev, struct vhost_virtqueue *vq,
+               uint64_t len, uint64_t len1, uint64_t len2, uint64_t len3,
+               uint16_t id, uint16_t id1, uint16_t id2, uint16_t id3,
+               uint16_t flags)
+{
+       vq->desc_packed[vq->last_used_idx].id = id;
+       vq->desc_packed[vq->last_used_idx].len = len;
+       vq->desc_packed[vq->last_used_idx + 1].id = id1;
+       vq->desc_packed[vq->last_used_idx + 1].len = len1;
+
+       vq->desc_packed[vq->last_used_idx + 2].id = id2;
+       vq->desc_packed[vq->last_used_idx + 2].len = len2;
+
+       vq->desc_packed[vq->last_used_idx + 3].id = id3;
+       vq->desc_packed[vq->last_used_idx + 3].len = len3;
+
+       rte_smp_wmb();
+       vq->desc_packed[vq->last_used_idx].flags = flags;
+       rte_smp_wmb();
+       vq->desc_packed[vq->last_used_idx + 1].flags = flags;
+       rte_smp_wmb();
+       vq->desc_packed[vq->last_used_idx + 2].flags = flags;
+       rte_smp_wmb();
+       vq->desc_packed[vq->last_used_idx + 3].flags = flags;
+
+       vhost_log_cache_used_vring(dev, vq,
+                               vq->last_used_idx *
+                               sizeof(struct vring_packed_desc),
+                               RTE_CACHE_LINE_SIZE);
+       vhost_log_cache_sync(dev, vq);
+
+       vq->last_used_idx += PACKED_DESC_PER_CACHELINE;
+       if (vq->last_used_idx >= vq->size) {
+               vq->used_wrap_counter ^= 1;
+               vq->last_used_idx -= vq->size;
+       }
+}
+
+static __rte_always_inline void
+flush_enqueue_fast_used_packed(struct virtio_net *dev,
+                       struct vhost_virtqueue *vq, uint64_t len,
+                       uint64_t len1, uint64_t len2, uint64_t len3,
+                       uint16_t id, uint16_t id1, uint16_t id2, uint16_t id3)
+{
+       uint16_t flags = 0;
+
+       if (vq->used_wrap_counter)
+               flags = VIRTIO_RX_FLAG_PACKED;
+       else
+               flags = VIRTIO_RX_WRAP_FLAG_PACKED;
+
+       flush_used_fast_packed(dev, vq, len, len1, len2, len3, id, id1, id2,
+                       id3, flags);
+}
+
 static __rte_always_inline void
 update_enqueue_shadow_used_ring_packed(struct vhost_virtqueue *vq,
                                uint16_t desc_idx, uint32_t len,
@@ -1020,6 +1077,7 @@ virtio_dev_rx_fast_packed(struct virtio_net *dev, struct 
vhost_virtqueue *vq,
                len2, len3;
        struct virtio_net_hdr_mrg_rxbuf *hdr, *hdr1, *hdr2, *hdr3;
        uint32_t buf_offset = dev->vhost_hlen;
+       uint16_t id, id1, id2, id3;
 
        if (unlikely(avail_idx & 0x3))
                return -1;
@@ -1055,6 +1113,11 @@ virtio_dev_rx_fast_packed(struct virtio_net *dev, struct 
vhost_virtqueue *vq,
                (pkts[3]->pkt_len > (len3 - buf_offset))))
                return -1;
 
+       id = descs[avail_idx].id;
+       id1 = descs[avail_idx + 1].id;
+       id2 = descs[avail_idx + 2].id;
+       id3 = descs[avail_idx + 3].id;
+
        desc_addr = vhost_iova_to_vva(dev, vq,
                        descs[avail_idx].addr,
                        &len,
@@ -1115,6 +1178,9 @@ virtio_dev_rx_fast_packed(struct virtio_net *dev, struct 
vhost_virtqueue *vq,
                rte_pktmbuf_mtod_offset(pkts[3], void *, 0),
                pkts[3]->pkt_len);
 
+       flush_enqueue_fast_used_packed(dev, vq, len, len1, len2, len3, id,
+               id1, id2, id3);
+
        return 0;
 }
 
-- 
2.17.1