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From: patrick.fu@intel.com
To: dev@dpdk.org, maxime.coquelin@redhat.com, chenbo.xia@intel.com
Cc: patrick.fu@intel.com, yinan.wang@intel.com
Subject: [dpdk-dev] [PATCH v2] vhost: support async copy free segmentations
Date: Wed, 15 Jul 2020 19:15:20 +0800
Message-ID: <20200715111520.2755307-1-patrick.fu@intel.com> (raw)
In-Reply-To: <20200715074650.2375332-1-patrick.fu@intel.com>

From: Patrick Fu <patrick.fu@intel.com>

Vhost async enqueue assumes that all async copies should break at packet
boundary. i.e. if a packet is splited into multiple copy segments, the
async engine should always report copy completion when entire packet is
finished. This patch removes the assumption.

Fixes: cd6760da1076 ("vhost: introduce async enqueue for split ring")

Signed-off-by: Patrick Fu <patrick.fu@intel.com>
---
v2:
 - fix an issue that can stuck async poll when packets buffer is full
 - rename a local variable to better reflect its usage

 lib/librte_vhost/vhost.h      |  3 +++
 lib/librte_vhost/virtio_net.c | 17 ++++++++++++-----
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index 8c01cee42..0f7212f88 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -46,6 +46,8 @@
 
 #define MAX_PKT_BURST 32
 
+#define ASYNC_MAX_POLL_SEG 255
+
 #define VHOST_MAX_ASYNC_IT (MAX_PKT_BURST * 2)
 #define VHOST_MAX_ASYNC_VEC (BUF_VECTOR_MAX * 2)
 
@@ -225,6 +227,7 @@ struct vhost_virtqueue {
 	uint64_t	*async_pending_info;
 	uint16_t	async_pkts_idx;
 	uint16_t	async_pkts_inflight_n;
+	uint16_t	async_last_seg_n;
 
 	/* vq async features */
 	bool		async_inorder;
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 1d0be3dd4..17808ab29 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -1633,6 +1633,7 @@ uint16_t rte_vhost_poll_enqueue_completed(int vid, uint16_t queue_id,
 	struct vhost_virtqueue *vq;
 	uint16_t n_pkts_cpl, n_pkts_put = 0, n_descs = 0;
 	uint16_t start_idx, pkts_idx, vq_size;
+	uint16_t n_inflight;
 	uint64_t *async_pending_info;
 
 	VHOST_LOG_DATA(DEBUG, "(%d) %s\n", dev->vid, __func__);
@@ -1646,28 +1647,32 @@ uint16_t rte_vhost_poll_enqueue_completed(int vid, uint16_t queue_id,
 
 	rte_spinlock_lock(&vq->access_lock);
 
+	n_inflight = vq->async_pkts_inflight_n;
 	pkts_idx = vq->async_pkts_idx;
 	async_pending_info = vq->async_pending_info;
 	vq_size = vq->size;
 	start_idx = virtio_dev_rx_async_get_info_idx(pkts_idx,
 		vq_size, vq->async_pkts_inflight_n);
 
-	n_pkts_cpl =
-		vq->async_ops.check_completed_copies(vid, queue_id, 0, count);
+	n_pkts_cpl = vq->async_ops.check_completed_copies(vid, queue_id,
+		0, ASYNC_MAX_POLL_SEG - vq->async_last_seg_n) +
+		vq->async_last_seg_n;
 
 	rte_smp_wmb();
 
-	while (likely(((start_idx + n_pkts_put) & (vq_size - 1)) != pkts_idx)) {
+	while (likely((n_pkts_put < count) && n_inflight)) {
 		uint64_t info = async_pending_info[
 			(start_idx + n_pkts_put) & (vq_size - 1)];
 		uint64_t n_segs;
 		n_pkts_put++;
+		n_inflight--;
 		n_descs += info & ASYNC_PENDING_INFO_N_MSK;
 		n_segs = info >> ASYNC_PENDING_INFO_N_SFT;
 
 		if (n_segs) {
-			if (!n_pkts_cpl || n_pkts_cpl < n_segs) {
+			if (unlikely(n_pkts_cpl < n_segs)) {
 				n_pkts_put--;
+				n_inflight++;
 				n_descs -= info & ASYNC_PENDING_INFO_N_MSK;
 				if (n_pkts_cpl) {
 					async_pending_info[
@@ -1684,8 +1689,10 @@ uint16_t rte_vhost_poll_enqueue_completed(int vid, uint16_t queue_id,
 		}
 	}
 
+	vq->async_last_seg_n = n_pkts_cpl;
+
 	if (n_pkts_put) {
-		vq->async_pkts_inflight_n -= n_pkts_put;
+		vq->async_pkts_inflight_n = n_inflight;
 		__atomic_add_fetch(&vq->used->idx, n_descs, __ATOMIC_RELEASE);
 
 		vhost_vring_call_split(dev, vq);
-- 
2.18.4


  reply	other threads:[~2020-07-15 11:16 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-15  7:46 [dpdk-dev] [PATCH v1] " patrick.fu
2020-07-15 11:15 ` patrick.fu [this message]
2020-07-17  3:21   ` [dpdk-dev] [PATCH v2] " Xia, Chenbo
2020-07-17 11:52     ` Ferruh Yigit
2020-07-20 14:58   ` Maxime Coquelin
2020-07-20 16:49     ` Ferruh Yigit
2020-07-21  5:52     ` Fu, Patrick
2020-07-21  5:47 ` [dpdk-dev] [PATCH v3] vhost: fix wrong async completion of multi-seg packets patrick.fu
2020-07-21  8:40   ` Maxime Coquelin
2020-07-21 14:57     ` Ferruh Yigit

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