By comparing the traffic information in the complete napi processes,
let the virtio-net driver automatically adjust the coalescing
moderation parameters of each receive queue.
Signed-off-by: Heng Qi <hen...@linux.alibaba.com>
---
v7->v8:
- Add select DIMLIB
v6->v7:
- Drop the patch titled "spin lock for ctrl cmd access"
- Use rtnl_trylock to avoid the deadlock.
v5->v6:
- Use spin lock and cancel_work_sync to synchronize
v4->v5:
- Fix possible synchronization issues using cancel_work().
- Reduce if/else nesting levels
v2->v3:
- Some minor modifications.
v1->v2:
- Improved the judgment of dim switch conditions.
- Cancel the work when vq reset.
drivers/net/Kconfig | 1 +
drivers/net/virtio_net.c | 176 +++++++++++++++++++++++++++++++++++----
2 files changed, 163 insertions(+), 14 deletions(-)
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index af0da4bb429b..8ca0bc223b30 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -434,6 +434,7 @@ config VIRTIO_NET
tristate "Virtio network driver"
depends on VIRTIO
select NET_FAILOVER
+ select DIMLIB
help
This is the virtual network driver for virtio. It can be used with
QEMU based VMMs (like KVM or Xen). Say Y or M.
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 69fe09e99b3c..10614e9f7cad 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -19,6 +19,7 @@
#include <linux/average.h>
#include <linux/filter.h>
#include <linux/kernel.h>
+#include <linux/dim.h>
#include <net/route.h>
#include <net/xdp.h>
#include <net/net_failover.h>
@@ -172,6 +173,17 @@ struct receive_queue {
struct virtnet_rq_stats stats;
+ /* The number of rx notifications */
+ u16 calls;
+
+ /* Is dynamic interrupt moderation enabled? */
+ bool dim_enabled;
+
+ /* Dynamic Interrupt Moderation */
+ struct dim dim;
+
+ u32 packets_in_napi;
+
struct virtnet_interrupt_coalesce intr_coal;
/* Chain pages by the private ptr. */
@@ -305,6 +317,9 @@ struct virtnet_info {
u8 duplex;
u32 speed;
+ /* Is rx dynamic interrupt moderation enabled? */
+ bool rx_dim_enabled;
+
/* Interrupt coalescing settings */
struct virtnet_interrupt_coalesce intr_coal_tx;
struct virtnet_interrupt_coalesce intr_coal_rx;
@@ -2001,6 +2016,7 @@ static void skb_recv_done(struct virtqueue *rvq)
struct virtnet_info *vi = rvq->vdev->priv;
struct receive_queue *rq = &vi->rq[vq2rxq(rvq)];
+ rq->calls++;
virtqueue_napi_schedule(&rq->napi, rvq);
}
@@ -2141,6 +2157,24 @@ static void virtnet_poll_cleantx(struct receive_queue
*rq)
}
}
+static void virtnet_rx_dim_update(struct virtnet_info *vi, struct
receive_queue *rq)
+{
+ struct dim_sample cur_sample = {};
+
+ if (!rq->packets_in_napi)
+ return;
+
+ u64_stats_update_begin(&rq->stats.syncp);
+ dim_update_sample(rq->calls,
+ u64_stats_read(&rq->stats.packets),
+ u64_stats_read(&rq->stats.bytes),
+ &cur_sample);
+ u64_stats_update_end(&rq->stats.syncp);
+
+ net_dim(&rq->dim, cur_sample);
+ rq->packets_in_napi = 0;
+}
+
static int virtnet_poll(struct napi_struct *napi, int budget)
{
struct receive_queue *rq =
@@ -2149,17 +2183,22 @@ static int virtnet_poll(struct napi_struct *napi, int
budget)
struct send_queue *sq;
unsigned int received;
unsigned int xdp_xmit = 0;
+ bool napi_complete;
virtnet_poll_cleantx(rq);
received = virtnet_receive(rq, budget, &xdp_xmit);
+ rq->packets_in_napi += received;
if (xdp_xmit & VIRTIO_XDP_REDIR)
xdp_do_flush();
/* Out of packets? */
- if (received < budget)
- virtqueue_napi_complete(napi, rq->vq, received);
+ if (received < budget) {
+ napi_complete = virtqueue_napi_complete(napi, rq->vq, received);
+ if (napi_complete && rq->dim_enabled)
+ virtnet_rx_dim_update(vi, rq);
+ }
if (xdp_xmit & VIRTIO_XDP_TX) {
sq = virtnet_xdp_get_sq(vi);
@@ -2230,8 +2269,11 @@ static int virtnet_open(struct net_device *dev)
disable_delayed_refill(vi);
cancel_delayed_work_sync(&vi->refill);
- for (i--; i >= 0; i--)
+ for (i--; i >= 0; i--) {
virtnet_disable_queue_pair(vi, i);
+ cancel_work_sync(&vi->rq[i].dim.work);
+ }
+
return err;
}
@@ -2393,8 +2435,10 @@ static int virtnet_rx_resize(struct virtnet_info *vi,
qindex = rq - vi->rq;
- if (running)
+ if (running) {
napi_disable(&rq->napi);
+ cancel_work_sync(&rq->dim.work);
+ }
err = virtqueue_resize(rq->vq, ring_num, virtnet_rq_free_unused_buf);
if (err)
@@ -2641,8 +2685,10 @@ static int virtnet_close(struct net_device *dev)
/* Make sure refill_work doesn't re-enable napi! */
cancel_delayed_work_sync(&vi->refill);
- for (i = 0; i < vi->max_queue_pairs; i++)
+ for (i = 0; i < vi->max_queue_pairs; i++) {
virtnet_disable_queue_pair(vi, i);
+ cancel_work_sync(&vi->rq[i].dim.work);
+ }
return 0;
}
@@ -2914,9 +2960,6 @@ static void virtnet_get_ringparam(struct net_device *dev,
ring->tx_pending = virtqueue_get_vring_size(vi->sq[0].vq);
}
-static int virtnet_send_ctrl_coal_vq_cmd(struct virtnet_info *vi,
- u16 vqn, u32 max_usecs, u32
max_packets);
-
static int virtnet_set_ringparam(struct net_device *dev,
struct ethtool_ringparam *ring,
struct kernel_ethtool_ringparam *kernel_ring,
@@ -3327,7 +3370,6 @@ static int virtnet_send_tx_notf_coal_cmds(struct
virtnet_info *vi,
&sgs_tx))
return -EINVAL;
- /* Save parameters */
vi->intr_coal_tx.max_usecs = ec->tx_coalesce_usecs;
vi->intr_coal_tx.max_packets = ec->tx_max_coalesced_frames;
for (i = 0; i < vi->max_queue_pairs; i++) {
@@ -3341,9 +3383,34 @@ static int virtnet_send_tx_notf_coal_cmds(struct
virtnet_info *vi,
static int virtnet_send_rx_notf_coal_cmds(struct virtnet_info *vi,
struct ethtool_coalesce *ec)
{
+ bool rx_ctrl_dim_on = !!ec->use_adaptive_rx_coalesce;
struct scatterlist sgs_rx;
int i;
+ if (rx_ctrl_dim_on && !virtio_has_feature(vi->vdev,
VIRTIO_NET_F_VQ_NOTF_COAL))
+ return -EOPNOTSUPP;
+
+ if (rx_ctrl_dim_on && (ec->rx_coalesce_usecs !=
vi->intr_coal_rx.max_usecs ||
+ ec->rx_max_coalesced_frames !=
vi->intr_coal_rx.max_packets))
+ return -EINVAL;
+
+ if (rx_ctrl_dim_on && !vi->rx_dim_enabled) {
+ vi->rx_dim_enabled = true;
+ for (i = 0; i < vi->max_queue_pairs; i++)
+ vi->rq[i].dim_enabled = true;
+ return 0;
+ }
+
+ if (!rx_ctrl_dim_on && vi->rx_dim_enabled) {
+ vi->rx_dim_enabled = false;
+ for (i = 0; i < vi->max_queue_pairs; i++)
+ vi->rq[i].dim_enabled = false;
+ }
+
+ /* Since the per-queue coalescing params can be set,
+ * we need apply the global new params even if they
+ * are not updated.
+ */
vi->ctrl->coal_rx.rx_usecs = cpu_to_le32(ec->rx_coalesce_usecs);
vi->ctrl->coal_rx.rx_max_packets =
cpu_to_le32(ec->rx_max_coalesced_frames);
sg_init_one(&sgs_rx, &vi->ctrl->coal_rx, sizeof(vi->ctrl->coal_rx));
@@ -3353,7 +3420,6 @@ static int virtnet_send_rx_notf_coal_cmds(struct
virtnet_info *vi,
&sgs_rx))
return -EINVAL;
- /* Save parameters */
vi->intr_coal_rx.max_usecs = ec->rx_coalesce_usecs;
vi->intr_coal_rx.max_packets = ec->rx_max_coalesced_frames;
for (i = 0; i < vi->max_queue_pairs; i++) {
@@ -3380,18 +3446,52 @@ static int virtnet_send_notf_coal_cmds(struct
virtnet_info *vi,
return 0;
}
-static int virtnet_send_notf_coal_vq_cmds(struct virtnet_info *vi,
- struct ethtool_coalesce *ec,
- u16 queue)
+static int virtnet_send_rx_notf_coal_vq_cmds(struct virtnet_info *vi,
+ struct ethtool_coalesce *ec,
+ u16 queue)
{
+ bool rx_ctrl_dim_on = !!ec->use_adaptive_rx_coalesce;
+ bool cur_rx_dim = vi->rq[queue].dim_enabled;
+ u32 max_usecs, max_packets;
int err;
+ max_usecs = vi->rq[queue].intr_coal.max_usecs;
+ max_packets = vi->rq[queue].intr_coal.max_packets;
+
+ if (rx_ctrl_dim_on && (ec->rx_coalesce_usecs != max_usecs ||
+ ec->rx_max_coalesced_frames != max_packets))
+ return -EINVAL;
+
+ if (rx_ctrl_dim_on && !cur_rx_dim) {
+ vi->rq[queue].dim_enabled = true;
+ return 0;
+ }
+
+ if (!rx_ctrl_dim_on && cur_rx_dim)
+ vi->rq[queue].dim_enabled = false;
+
+ /* If no params are updated, userspace ethtool will
+ * reject the modification.
+ */
err = virtnet_send_rx_ctrl_coal_vq_cmd(vi, queue,
ec->rx_coalesce_usecs,
ec->rx_max_coalesced_frames);
if (err)
return err;
+ return 0;
+}
+
+static int virtnet_send_notf_coal_vq_cmds(struct virtnet_info *vi,
+ struct ethtool_coalesce *ec,
+ u16 queue)
+{
+ int err;
+
+ err = virtnet_send_rx_notf_coal_vq_cmds(vi, ec, queue);
+ if (err)
+ return err;
+
err = virtnet_send_tx_ctrl_coal_vq_cmd(vi, queue,
ec->tx_coalesce_usecs,
ec->tx_max_coalesced_frames);
@@ -3401,6 +3501,49 @@ static int virtnet_send_notf_coal_vq_cmds(struct
virtnet_info *vi,
return 0;
}
+static void virtnet_rx_dim_work(struct work_struct *work)
+{
+ struct dim *dim = container_of(work, struct dim, work);
+ struct receive_queue *rq = container_of(dim,
+ struct receive_queue, dim);
+ struct virtnet_info *vi = rq->vq->vdev->priv;
+ struct net_device *dev = vi->dev;
+ struct dim_cq_moder update_moder;
+ int i, qnum, err;
+
+ if (!rtnl_trylock())
+ return;
+
+ /* Each rxq's work is queued by "net_dim()->schedule_work()"
+ * in response to NAPI traffic changes. Note that dim->profile_ix
+ * for each rxq is updated prior to the queuing action.
+ * So we only need to traverse and update profiles for all rxqs
+ * in the work which is holding rtnl_lock.
+ */
+ for (i = 0; i < vi->curr_queue_pairs; i++) {
+ rq = &vi->rq[i];
+ dim = &rq->dim;
+ qnum = rq - vi->rq;
+
+ if (!rq->dim_enabled)
+ continue;
+
+ update_moder = net_dim_get_rx_moderation(dim->mode,
dim->profile_ix);
+ if (update_moder.usec != rq->intr_coal.max_usecs ||
+ update_moder.pkts != rq->intr_coal.max_packets) {
+ err = virtnet_send_rx_ctrl_coal_vq_cmd(vi, qnum,
+
update_moder.usec,
+
update_moder.pkts);
+ if (err)
+ pr_debug("%s: Failed to send dim parameters on
rxq%d\n",
+ dev->name, qnum);
+ dim->state = DIM_START_MEASURE;
+ }
+ }
+
+ rtnl_unlock();
+}
+
static int virtnet_coal_params_supported(struct ethtool_coalesce *ec)
{
/* usecs coalescing is supported only if VIRTIO_NET_F_NOTF_COAL
@@ -3482,6 +3625,7 @@ static int virtnet_get_coalesce(struct net_device *dev,
ec->tx_coalesce_usecs = vi->intr_coal_tx.max_usecs;
ec->tx_max_coalesced_frames = vi->intr_coal_tx.max_packets;
ec->rx_max_coalesced_frames = vi->intr_coal_rx.max_packets;
+ ec->use_adaptive_rx_coalesce = vi->rx_dim_enabled;
} else {
ec->rx_max_coalesced_frames = 1;
@@ -3539,6 +3683,7 @@ static int virtnet_get_per_queue_coalesce(struct
net_device *dev,
ec->tx_coalesce_usecs = vi->sq[queue].intr_coal.max_usecs;
ec->tx_max_coalesced_frames =
vi->sq[queue].intr_coal.max_packets;
ec->rx_max_coalesced_frames =
vi->rq[queue].intr_coal.max_packets;
+ ec->use_adaptive_rx_coalesce = vi->rq[queue].dim_enabled;
} else {
ec->rx_max_coalesced_frames = 1;
@@ -3664,7 +3809,7 @@ static int virtnet_set_rxnfc(struct net_device *dev,
struct ethtool_rxnfc *info)
static const struct ethtool_ops virtnet_ethtool_ops = {
.supported_coalesce_params = ETHTOOL_COALESCE_MAX_FRAMES |
- ETHTOOL_COALESCE_USECS,
+ ETHTOOL_COALESCE_USECS | ETHTOOL_COALESCE_USE_ADAPTIVE_RX,
.get_drvinfo = virtnet_get_drvinfo,
.get_link = ethtool_op_get_link,
.get_ringparam = virtnet_get_ringparam,
@@ -4254,6 +4399,9 @@ static int virtnet_alloc_queues(struct virtnet_info *vi)
virtnet_poll_tx,
napi_tx ? napi_weight : 0);
+ INIT_WORK(&vi->rq[i].dim.work, virtnet_rx_dim_work);
+ vi->rq[i].dim.mode = DIM_CQ_PERIOD_MODE_START_FROM_EQE;
+
sg_init_table(vi->rq[i].sg, ARRAY_SIZE(vi->rq[i].sg));
ewma_pkt_len_init(&vi->rq[i].mrg_avg_pkt_len);
sg_init_table(vi->sq[i].sg, ARRAY_SIZE(vi->sq[i].sg));
--
2.19.1.6.gb485710b
