> -----Original Message----- > From: Maxime Coquelin [mailto:maxime.coque...@redhat.com] > Sent: Wednesday, October 16, 2019 6:36 PM > To: Liu, Yong <yong....@intel.com>; Bie, Tiwei <tiwei....@intel.com>; Wang, > Zhihong <zhihong.w...@intel.com>; step...@networkplumber.org; > gavin...@arm.com > Cc: dev@dpdk.org > Subject: Re: [PATCH v6 06/13] vhost: add packed ring batch dequeue > > > > On 10/15/19 6:07 PM, Marvin Liu wrote: > > Add batch dequeue function like enqueue function for packed ring, batch > > dequeue function will not support chained descritpors, single packet > > dequeue function will handle it. > > > > Signed-off-by: Marvin Liu <yong....@intel.com> > > > > diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h > > index 18d01cb19..96bf763b1 100644 > > --- a/lib/librte_vhost/vhost.h > > +++ b/lib/librte_vhost/vhost.h > > @@ -39,6 +39,9 @@ > > > > #define VHOST_LOG_CACHE_NR 32 > > > > +#define PACKED_DESC_SINGLE_DEQUEUE_FLAG (VRING_DESC_F_NEXT | \ > > + VRING_DESC_F_INDIRECT) > > + > > #define PACKED_BATCH_SIZE (RTE_CACHE_LINE_SIZE / \ > > sizeof(struct vring_packed_desc)) > > #define PACKED_BATCH_MASK (PACKED_BATCH_SIZE - 1) > > diff --git a/lib/librte_vhost/virtio_net.c > b/lib/librte_vhost/virtio_net.c > > index e1b06c1ce..274a28f99 100644 > > --- a/lib/librte_vhost/virtio_net.c > > +++ b/lib/librte_vhost/virtio_net.c > > @@ -1551,6 +1551,113 @@ virtio_dev_tx_split(struct virtio_net *dev, > struct vhost_virtqueue *vq, > > return i; > > } > > > > +static __rte_always_inline int > > +vhost_reserve_avail_batch_packed(struct virtio_net *dev, > > + struct vhost_virtqueue *vq, > > + struct rte_mempool *mbuf_pool, > > + struct rte_mbuf **pkts, > > + uint16_t avail_idx, > > + uintptr_t *desc_addrs, > > + uint16_t *ids) > > +{ > > + bool wrap = vq->avail_wrap_counter; > > + struct vring_packed_desc *descs = vq->desc_packed; > > + struct virtio_net_hdr *hdr; > > + uint64_t lens[PACKED_BATCH_SIZE]; > > + uint64_t buf_lens[PACKED_BATCH_SIZE]; > > + uint32_t buf_offset = dev->vhost_hlen; > > + uint16_t flags, i; > > + > > + if (unlikely(avail_idx & PACKED_BATCH_MASK)) > > + return -1; > > + if (unlikely((avail_idx + PACKED_BATCH_SIZE) > vq->size)) > > + return -1; > > + > > + for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) { > > + flags = descs[avail_idx + i].flags; > > + if (unlikely((wrap != !!(flags & VRING_DESC_F_AVAIL)) || > > + (wrap == !!(flags & VRING_DESC_F_USED)) || > > + (flags & PACKED_DESC_SINGLE_DEQUEUE_FLAG))) > > + return -1; > > + } > > + > > + rte_smp_rmb(); > > + > > + for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) > > + lens[i] = descs[avail_idx + i].len; > > + > > + for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) { > > + desc_addrs[i] = vhost_iova_to_vva(dev, vq, > > + descs[avail_idx + i].addr, > > + &lens[i], VHOST_ACCESS_RW); > > + } > > + > > + for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) { > > + if (unlikely((lens[i] != descs[avail_idx + i].len))) > > + return -1; > > + } > > + > > + if (rte_pktmbuf_alloc_bulk(mbuf_pool, pkts, PACKED_BATCH_SIZE)) > > + return -1; > > + > > + for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) > > + buf_lens[i] = pkts[i]->buf_len - pkts[i]->data_off; > > + > > + for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) { > > + if (unlikely(buf_lens[i] < (lens[i] - buf_offset))) > > + goto free_buf; > > + } > > + > > + for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) { > > + pkts[i]->pkt_len = descs[avail_idx + i].len - buf_offset; > > + pkts[i]->data_len = pkts[i]->pkt_len; > > + ids[i] = descs[avail_idx + i].id; > > + } > > + > > + if (virtio_net_with_host_offload(dev)) { > > + for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) { > > + hdr = (struct virtio_net_hdr *)(desc_addrs[i]); > > + vhost_dequeue_offload(hdr, pkts[i]); > > + } > > + } > > + > > + return 0; > > + > > +free_buf: > > + for (i = 0; i < PACKED_BATCH_SIZE; i++) > > + rte_pktmbuf_free(pkts[i]); > > + > > + return -1; > > +} > > + > > +static __rte_unused int > > +virtio_dev_tx_batch_packed(struct virtio_net *dev, > > + struct vhost_virtqueue *vq, > > + struct rte_mempool *mbuf_pool, > > + struct rte_mbuf **pkts) > > +{ > > + uint16_t avail_idx = vq->last_avail_idx; > > + uint32_t buf_offset = dev->vhost_hlen; > > + uintptr_t desc_addrs[PACKED_BATCH_SIZE]; > > + uint16_t ids[PACKED_BATCH_SIZE]; > > + uint16_t i; > > + > > + if (vhost_reserve_avail_batch_packed(dev, vq, mbuf_pool, pkts, > > + avail_idx, desc_addrs, ids)) > > + return -1; > > + > > + for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) { > > + rte_prefetch0((void *)(uintptr_t)desc_addrs[i]); > > Wouldn't we have better performance with a dedicated unroll loop for the > prefetches, so that desc_addrs[i+1] is being prefetched while the > desc_addr[i] memcpy is done? > Thanks, Maxime. It will be slightly better. Will have dedicated unroll loop in next version.
Regards, marvin > > + rte_memcpy(rte_pktmbuf_mtod_offset(pkts[i], void *, 0), > > + (void *)(uintptr_t)(desc_addrs[i] + buf_offset), > > + pkts[i]->pkt_len); > > + } > > + > > + vq_inc_last_avail_packed(vq, PACKED_BATCH_SIZE); > > + > > + return 0; > > +} > > + > > static __rte_always_inline int > > vhost_dequeue_single_packed(struct virtio_net *dev, > > struct vhost_virtqueue *vq, > >
