From: Yuanhan Liu <yuanhan.liu@linux.intel.com>
To: dev@dpdk.org
Cc: Maxime Coquelin <maxime.coquelin@redhat.com>,
Yuanhan Liu <yuanhan.liu@linux.intel.com>
Subject: [dpdk-dev] [PATCH v2 3/7] vhost: introduce last avail idx for dequeue
Date: Fri, 23 Sep 2016 12:13:23 +0800 [thread overview]
Message-ID: <1474604007-5221-4-git-send-email-yuanhan.liu@linux.intel.com> (raw)
In-Reply-To: <1474604007-5221-1-git-send-email-yuanhan.liu@linux.intel.com>
So far, we retrieve both the used ring and avail ring idx by the var
last_used_idx; it won't be a problem because the used ring is updated
immediately after those avail entries are consumed.
But that's not true when dequeue zero copy is enabled, that used ring is
updated only when the mbuf is consumed. Thus, we need use another var to
note the last avail ring idx we have consumed.
Therefore, last_avail_idx is introduced.
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
lib/librte_vhost/vhost.h | 2 +-
lib/librte_vhost/vhost_user.c | 6 ++++--
lib/librte_vhost/virtio_net.c | 19 +++++++++++--------
3 files changed, 16 insertions(+), 11 deletions(-)
diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index 2d52987..8565fa1 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -70,7 +70,7 @@ struct vhost_virtqueue {
struct vring_used *used;
uint32_t size;
- /* Last index used on the available ring */
+ uint16_t last_avail_idx;
volatile uint16_t last_used_idx;
#define VIRTIO_INVALID_EVENTFD (-1)
#define VIRTIO_UNINITIALIZED_EVENTFD (-2)
diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index e651912..a92377a 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -343,7 +343,8 @@ vhost_user_set_vring_addr(struct virtio_net *dev, struct vhost_vring_addr *addr)
"last_used_idx (%u) and vq->used->idx (%u) mismatches; "
"some packets maybe resent for Tx and dropped for Rx\n",
vq->last_used_idx, vq->used->idx);
- vq->last_used_idx = vq->used->idx;
+ vq->last_used_idx = vq->used->idx;
+ vq->last_avail_idx = vq->used->idx;
}
vq->log_guest_addr = addr->log_guest_addr;
@@ -367,7 +368,8 @@ static int
vhost_user_set_vring_base(struct virtio_net *dev,
struct vhost_vring_state *state)
{
- dev->virtqueue[state->index]->last_used_idx = state->num;
+ dev->virtqueue[state->index]->last_used_idx = state->num;
+ dev->virtqueue[state->index]->last_avail_idx = state->num;
return 0;
}
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 8a151af..1c2ee47 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -846,16 +846,17 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
}
}
- avail_idx = *((volatile uint16_t *)&vq->avail->idx);
- free_entries = avail_idx - vq->last_used_idx;
+ free_entries = *((volatile uint16_t *)&vq->avail->idx) -
+ vq->last_avail_idx;
if (free_entries == 0)
goto out;
LOG_DEBUG(VHOST_DATA, "(%d) %s\n", dev->vid, __func__);
- /* Prefetch available ring to retrieve head indexes. */
- used_idx = vq->last_used_idx & (vq->size - 1);
- rte_prefetch0(&vq->avail->ring[used_idx]);
+ /* 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);
@@ -865,8 +866,9 @@ 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++) {
- used_idx = (vq->last_used_idx + i) & (vq->size - 1);
- desc_indexes[i] = vq->avail->ring[used_idx];
+ 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];
vq->used->ring[used_idx].id = desc_indexes[i];
vq->used->ring[used_idx].len = 0;
@@ -900,7 +902,8 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
rte_smp_wmb();
rte_smp_rmb();
vq->used->idx += i;
- vq->last_used_idx += i;
+ vq->last_avail_idx += i;
+ vq->last_used_idx += i;
vhost_log_used_vring(dev, vq, offsetof(struct vring_used, idx),
sizeof(vq->used->idx));
--
1.9.0
next prev parent reply other threads:[~2016-09-23 4:13 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-23 8:10 [dpdk-dev] [PATCH 0/6] vhost: add Tx zero copy support Yuanhan Liu
2016-08-23 8:10 ` [dpdk-dev] [PATCH 1/6] vhost: simplify memory regions handling Yuanhan Liu
2016-08-23 9:17 ` Maxime Coquelin
2016-08-24 7:26 ` Xu, Qian Q
2016-08-24 7:40 ` Yuanhan Liu
2016-08-24 7:36 ` Xu, Qian Q
2016-08-23 8:10 ` [dpdk-dev] [PATCH 2/6] vhost: get guest/host physical address mappings Yuanhan Liu
2016-08-23 9:58 ` Maxime Coquelin
2016-08-23 12:32 ` Yuanhan Liu
2016-08-23 13:25 ` Maxime Coquelin
2016-08-23 13:49 ` Yuanhan Liu
2016-08-23 14:05 ` Maxime Coquelin
2016-08-23 8:10 ` [dpdk-dev] [PATCH 3/6] vhost: introduce last avail idx for Tx Yuanhan Liu
2016-08-23 12:27 ` Maxime Coquelin
2016-08-23 8:10 ` [dpdk-dev] [PATCH 4/6] vhost: add Tx zero copy Yuanhan Liu
2016-08-23 14:04 ` Maxime Coquelin
2016-08-23 14:31 ` Yuanhan Liu
2016-08-23 15:40 ` Maxime Coquelin
2016-08-23 8:10 ` [dpdk-dev] [PATCH 5/6] vhost: add a flag to enable " Yuanhan Liu
2016-09-06 9:00 ` Xu, Qian Q
2016-09-06 9:42 ` Xu, Qian Q
2016-09-06 10:02 ` Yuanhan Liu
2016-09-07 2:43 ` Xu, Qian Q
2016-09-06 9:55 ` Yuanhan Liu
2016-09-07 16:00 ` Thomas Monjalon
2016-09-08 7:21 ` Yuanhan Liu
2016-09-08 7:57 ` Thomas Monjalon
2016-08-23 8:10 ` [dpdk-dev] [PATCH 6/6] examples/vhost: add an option " Yuanhan Liu
2016-08-23 9:31 ` Thomas Monjalon
2016-08-23 12:33 ` Yuanhan Liu
2016-08-23 14:14 ` Maxime Coquelin
2016-08-23 14:45 ` Yuanhan Liu
2016-08-23 14:18 ` [dpdk-dev] [PATCH 0/6] vhost: add Tx zero copy support Maxime Coquelin
2016-08-23 14:42 ` Yuanhan Liu
2016-08-23 14:53 ` Yuanhan Liu
2016-08-23 16:41 ` Maxime Coquelin
2016-08-29 8:32 ` Xu, Qian Q
2016-08-29 8:57 ` Xu, Qian Q
2016-09-23 4:11 ` Yuanhan Liu
2016-10-09 15:20 ` Yuanhan Liu
2016-09-23 4:13 ` [dpdk-dev] [PATCH v2 0/7] vhost: add dequeue " Yuanhan Liu
2016-09-23 4:13 ` [dpdk-dev] [PATCH v2 1/7] vhost: simplify memory regions handling Yuanhan Liu
2016-09-23 4:13 ` [dpdk-dev] [PATCH v2 2/7] vhost: get guest/host physical address mappings Yuanhan Liu
2016-09-26 20:17 ` Maxime Coquelin
2016-09-23 4:13 ` Yuanhan Liu [this message]
2016-09-23 4:13 ` [dpdk-dev] [PATCH v2 4/7] vhost: add dequeue zero copy Yuanhan Liu
2016-09-26 20:45 ` Maxime Coquelin
2016-10-06 14:37 ` Xu, Qian Q
2016-10-09 2:03 ` Yuanhan Liu
2016-10-10 10:12 ` Xu, Qian Q
2016-10-10 10:14 ` Maxime Coquelin
2016-10-10 10:22 ` Xu, Qian Q
2016-10-10 10:40 ` Xu, Qian Q
2016-10-10 11:48 ` Maxime Coquelin
2016-09-23 4:13 ` [dpdk-dev] [PATCH v2 5/7] vhost: add a flag to enable " Yuanhan Liu
2016-09-26 20:57 ` Maxime Coquelin
2016-09-23 4:13 ` [dpdk-dev] [PATCH v2 6/7] examples/vhost: add an option " Yuanhan Liu
2016-09-26 21:05 ` Maxime Coquelin
2016-09-23 4:13 ` [dpdk-dev] [PATCH v2 7/7] net/vhost: " Yuanhan Liu
2016-09-26 21:05 ` Maxime Coquelin
2016-10-09 7:27 ` [dpdk-dev] [PATCH v3 0/7] vhost: add dequeue zero copy support Yuanhan Liu
2016-10-09 7:27 ` [dpdk-dev] [PATCH v3 1/7] vhost: simplify memory regions handling Yuanhan Liu
2016-10-09 7:27 ` [dpdk-dev] [PATCH v3 2/7] vhost: get guest/host physical address mappings Yuanhan Liu
2016-11-29 3:10 ` linhaifeng
2016-11-29 13:14 ` linhaifeng
2016-10-09 7:27 ` [dpdk-dev] [PATCH v3 3/7] vhost: introduce last avail idx for dequeue Yuanhan Liu
2016-10-09 7:27 ` [dpdk-dev] [PATCH v3 4/7] vhost: add dequeue zero copy Yuanhan Liu
2016-10-09 7:27 ` [dpdk-dev] [PATCH v3 5/7] vhost: add a flag to enable " Yuanhan Liu
2016-10-09 7:27 ` [dpdk-dev] [PATCH v3 6/7] examples/vhost: add an option " Yuanhan Liu
2016-10-09 7:28 ` [dpdk-dev] [PATCH v3 7/7] net/vhost: " Yuanhan Liu
2016-10-11 13:04 ` [dpdk-dev] [PATCH v3 0/7] vhost: add dequeue zero copy support Xu, Qian Q
2016-10-12 7:48 ` Yuanhan Liu
2016-10-09 10:46 ` [dpdk-dev] [PATCH 0/6] vhost: add Tx " linhaifeng
2016-10-10 8:03 ` Yuanhan Liu
2016-10-14 7:30 ` linhaifeng
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1474604007-5221-4-git-send-email-yuanhan.liu@linux.intel.com \
--to=yuanhan.liu@linux.intel.com \
--cc=dev@dpdk.org \
--cc=maxime.coquelin@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).