From: Maxime Coquelin <maxime.coquelin@redhat.com>
To: tiwei.bie@intel.com, zhihong.wang@intel.com, dev@dpdk.org
Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
Subject: [dpdk-dev] [PATCH v4 1/5] vhost: use shadow used ring in dequeue path
Date: Fri, 6 Jul 2018 09:04:45 +0200 [thread overview]
Message-ID: <20180706070449.1946-2-maxime.coquelin@redhat.com> (raw)
In-Reply-To: <20180706070449.1946-1-maxime.coquelin@redhat.com>
Relax used ring contention by reusing the shadow used
ring feature used by enqueue path.
Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
lib/librte_vhost/virtio_net.c | 50 +++++++++----------------------------------
1 file changed, 10 insertions(+), 40 deletions(-)
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 98ad8e936..741267345 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -1019,35 +1019,6 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq,
return error;
}
-static __rte_always_inline void
-update_used_ring(struct virtio_net *dev, struct vhost_virtqueue *vq,
- uint32_t used_idx, uint32_t desc_idx)
-{
- vq->used->ring[used_idx].id = desc_idx;
- vq->used->ring[used_idx].len = 0;
- vhost_log_cache_used_vring(dev, vq,
- offsetof(struct vring_used, ring[used_idx]),
- sizeof(vq->used->ring[used_idx]));
-}
-
-static __rte_always_inline void
-update_used_idx(struct virtio_net *dev, struct vhost_virtqueue *vq,
- uint32_t count)
-{
- if (unlikely(count == 0))
- return;
-
- rte_smp_wmb();
- rte_smp_rmb();
-
- vhost_log_cache_sync(dev, vq);
-
- vq->used->idx += count;
- vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
- sizeof(vq->used->idx));
- vhost_vring_call(dev, vq);
-}
-
static __rte_always_inline struct zcopy_mbuf *
get_zmbuf(struct vhost_virtqueue *vq)
{
@@ -1115,7 +1086,6 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
struct rte_mbuf *rarp_mbuf = NULL;
struct vhost_virtqueue *vq;
uint32_t desc_indexes[MAX_PKT_BURST];
- uint32_t used_idx;
uint32_t i = 0;
uint16_t free_entries;
uint16_t avail_idx;
@@ -1146,6 +1116,7 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
goto out_access_unlock;
vq->batch_copy_nb_elems = 0;
+ vq->shadow_used_idx = 0;
if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
vhost_user_iotlb_rd_lock(vq);
@@ -1163,9 +1134,7 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
next = TAILQ_NEXT(zmbuf, next);
if (mbuf_is_consumed(zmbuf->mbuf)) {
- used_idx = vq->last_used_idx++ & (vq->size - 1);
- update_used_ring(dev, vq, used_idx,
- zmbuf->desc_idx);
+ update_shadow_used_ring(vq, zmbuf->desc_idx, 0);
nr_updated += 1;
TAILQ_REMOVE(&vq->zmbuf_list, zmbuf, next);
@@ -1176,7 +1145,9 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
}
}
- update_used_idx(dev, vq, nr_updated);
+ flush_shadow_used_ring(dev, vq);
+ vhost_vring_call(dev, vq);
+ vq->shadow_used_idx = 0;
}
/*
@@ -1217,9 +1188,7 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
/* Prefetch available and used ring */
avail_idx = vq->last_avail_idx & (vq->size - 1);
- used_idx = vq->last_used_idx & (vq->size - 1);
rte_prefetch0(&vq->avail->ring[avail_idx]);
- rte_prefetch0(&vq->used->ring[used_idx]);
count = RTE_MIN(count, MAX_PKT_BURST);
count = RTE_MIN(count, free_entries);
@@ -1229,11 +1198,10 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
/* Retrieve all of the head indexes first to avoid caching issues. */
for (i = 0; i < count; i++) {
avail_idx = (vq->last_avail_idx + i) & (vq->size - 1);
- used_idx = (vq->last_used_idx + i) & (vq->size - 1);
desc_indexes[i] = vq->avail->ring[avail_idx];
if (likely(dev->dequeue_zero_copy == 0))
- update_used_ring(dev, vq, used_idx, desc_indexes[i]);
+ update_shadow_used_ring(vq, desc_indexes[i], 0);
}
/* Prefetch descriptor index. */
@@ -1326,8 +1294,10 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
if (likely(dev->dequeue_zero_copy == 0)) {
do_data_copy_dequeue(vq);
- vq->last_used_idx += i;
- update_used_idx(dev, vq, i);
+ if (unlikely(i < count))
+ vq->shadow_used_idx = i;
+ flush_shadow_used_ring(dev, vq);
+ vhost_vring_call(dev, vq);
}
out:
--
2.14.4
next prev parent reply other threads:[~2018-07-06 7:04 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-06 7:04 [dpdk-dev] [PATCH v4 0/5] vhost: generalize buffer vectors Maxime Coquelin
2018-07-06 7:04 ` Maxime Coquelin [this message]
2018-07-06 7:59 ` [dpdk-dev] [PATCH v4 1/5] vhost: use shadow used ring in dequeue path Maxime Coquelin
2018-07-06 7:04 ` [dpdk-dev] [PATCH v4 2/5] vhost: use buffer vectors " Maxime Coquelin
[not found] ` <2DBBFF226F7CF64BAFCA79B681719D953A4EB9E3@SHSMSX101.ccr.corp.intel.com>
[not found] ` <E0CBA5A1980F1F408E1F28F9991B5B1D50D03E40@SHSMSX104.ccr.corp.intel.com>
2018-07-17 7:17 ` Wang, Yinan
2018-07-06 7:04 ` [dpdk-dev] [PATCH v4 3/5] vhost: improve prefetching " Maxime Coquelin
2018-07-06 7:04 ` [dpdk-dev] [PATCH v4 4/5] vhost: prefetch first descriptor " Maxime Coquelin
2018-07-06 7:04 ` [dpdk-dev] [PATCH v4 5/5] vhost: improve prefetching in enqueue path Maxime Coquelin
2018-07-09 1:39 ` [dpdk-dev] [PATCH v4 0/5] vhost: generalize buffer vectors Tiwei Bie
2018-07-09 7:01 ` Tiwei Bie
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