[v3,1/5] net/virtio: implement rte_power_monitor API

  This patch implements rte_power_monitor API in virtio PMD to reduce
power consumption when no packet come in. According to current semantics
of power monitor, this commit adds a callback function to decide whether
aborts the sleep by checking current value against the expected value and
virtio_get_monitor_addr to provide address to monitor. When no packet come
in, the value of address will not be changed and the running core will
sleep. Once packets arrive, the value of address will be changed and the
running core will wakeup.

Signed-off-by: Miao Li <miao.li@intel.com>
---
 drivers/net/virtio/virtio_ethdev.c | 56 ++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
  

> -----Original Message-----
> From: Li, Miao <miao.li@intel.com>
> Sent: Friday, September 24, 2021 6:23 PM
> To: dev@dpdk.org
> Cc: Xia, Chenbo <chenbo.xia@intel.com>; maxime.coquelin@redhat.com; Li, Miao
> <miao.li@intel.com>
> Subject: [PATCH v3 1/5] net/virtio: implement rte_power_monitor API
> 
> This patch implements rte_power_monitor API in virtio PMD to reduce
> power consumption when no packet come in. According to current semantics
> of power monitor, this commit adds a callback function to decide whether
> aborts the sleep by checking current value against the expected value and
> virtio_get_monitor_addr to provide address to monitor. When no packet come
> in, the value of address will not be changed and the running core will
> sleep. Once packets arrive, the value of address will be changed and the
> running core will wakeup.
> 
> Signed-off-by: Miao Li <miao.li@intel.com>
> ---
>  drivers/net/virtio/virtio_ethdev.c | 56 ++++++++++++++++++++++++++++++
>  1 file changed, 56 insertions(+)
> 
> diff --git a/drivers/net/virtio/virtio_ethdev.c
> b/drivers/net/virtio/virtio_ethdev.c
> index e58085a2c9..63b2d8cb8d 100644
> --- a/drivers/net/virtio/virtio_ethdev.c
> +++ b/drivers/net/virtio/virtio_ethdev.c
> @@ -73,6 +73,8 @@ static int virtio_mac_addr_set(struct rte_eth_dev *dev,
>  				struct rte_ether_addr *mac_addr);
> 
>  static int virtio_intr_disable(struct rte_eth_dev *dev);
> +static int virtio_get_monitor_addr(void *rx_queue,
> +				struct rte_power_monitor_cond *pmc);
> 
>  static int virtio_dev_queue_stats_mapping_set(
>  	struct rte_eth_dev *eth_dev,
> @@ -975,6 +977,7 @@ static const struct eth_dev_ops virtio_eth_dev_ops = {
>  	.mac_addr_add            = virtio_mac_addr_add,
>  	.mac_addr_remove         = virtio_mac_addr_remove,
>  	.mac_addr_set            = virtio_mac_addr_set,
> +	.get_monitor_addr        = virtio_get_monitor_addr,
>  };
> 
>  /*
> @@ -1306,6 +1309,59 @@ virtio_mac_addr_set(struct rte_eth_dev *dev, struct
> rte_ether_addr *mac_addr)
>  	return 0;
>  }
> 
> +#define CLB_VAL_IDX 0
> +#define CLB_MSK_IDX 1
> +#define CLB_MATCH_IDX 2
> +static int
> +virtio_monitor_callback(const uint64_t value,
> +		const uint64_t opaque[RTE_POWER_MONITOR_OPAQUE_SZ])
> +{
> +	const uint64_t m = opaque[CLB_MSK_IDX];
> +	const uint64_t v = opaque[CLB_VAL_IDX];
> +	const uint64_t c = opaque[CLB_MATCH_IDX];
> +
> +	if (c)
> +		return (value & m) == v ? -1 : 0;
> +	else
> +		return (value & m) == v ? 0 : -1;
> +}
> +
> +static int
> +virtio_get_monitor_addr(void *rx_queue, struct rte_power_monitor_cond *pmc)
> +{
> +	struct virtnet_rx *rxvq = rx_queue;
> +	struct virtqueue *vq = virtnet_rxq_to_vq(rxvq);
> +	struct virtio_hw *hw;
> +
> +	if (vq == NULL)
> +		return -EINVAL;
> +
> +	hw = vq->hw;
> +	if (virtio_with_packed_queue(hw)) {
> +		struct vring_packed_desc *desc;
> +		desc = vq->vq_packed.ring.desc;
> +		pmc->addr = &desc[vq->vq_used_cons_idx].flags;
> +		if (vq->vq_packed.used_wrap_counter)
> +			pmc->opaque[CLB_VAL_IDX] =
> +						VRING_PACKED_DESC_F_AVAIL_USED;
> +		else
> +			pmc->opaque[CLB_VAL_IDX] = 0;
> +		pmc->opaque[CLB_MSK_IDX] = VRING_PACKED_DESC_F_AVAIL_USED;
> +		pmc->opaque[CLB_MATCH_IDX] = 1;
> +		pmc->size = sizeof(desc[vq->vq_used_cons_idx].flags);
> +	} else {
> +		pmc->addr = &vq->vq_split.ring.used->idx;
> +		pmc->opaque[CLB_VAL_IDX] = vq->vq_used_cons_idx
> +					& (vq->vq_nentries - 1);
> +		pmc->opaque[CLB_MSK_IDX] = vq->vq_nentries - 1;
> +		pmc->opaque[CLB_MATCH_IDX] = 0;
> +		pmc->size = sizeof(vq->vq_split.ring.used->idx);
> +	}
> +	pmc->fn = virtio_monitor_callback;
> +
> +	return 0;
> +}
> +
>  static int
>  virtio_vlan_filter_set(struct rte_eth_dev *dev, uint16_t vlan_id, int on)
>  {
> --
> 2.25.1

Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>