Re: [next-queue v2 2/4] i40e: Record number TXes cleaned during NAPI

["Samudrala, Sridhar" <sridhar.samudrala@intel.com>]

On 10/5/2022 4:21 PM, Joe Damato wrote:
> Update i40e_clean_tx_irq to take an out parameter (tx_cleaned) which stores
> the number TXs cleaned.
>
> Likewise, update i40e_clean_xdp_tx_irq and i40e_xmit_zc to do the same.
>
> Care has been taken to avoid changing the control flow of any functions
> involved.
>
> Signed-off-by: Joe Damato <jdamato@fastly.com>
> ---
>   drivers/net/ethernet/intel/i40e/i40e_txrx.c | 16 +++++++++++-----
>   drivers/net/ethernet/intel/i40e/i40e_xsk.c  | 15 +++++++++++----
>   drivers/net/ethernet/intel/i40e/i40e_xsk.h  |  3 ++-
>   3 files changed, 24 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
> index b97c95f..a2cc98e 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
> +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
> @@ -923,11 +923,13 @@ void i40e_detect_recover_hung(struct i40e_vsi *vsi)
>    * @vsi: the VSI we care about
>    * @tx_ring: Tx ring to clean
>    * @napi_budget: Used to determine if we are in netpoll
> + * @tx_cleaned: Out parameter set to the number of TXes cleaned
>    *
>    * Returns true if there's any budget left (e.g. the clean is finished)
>    **/
>   static bool i40e_clean_tx_irq(struct i40e_vsi *vsi,
> -			      struct i40e_ring *tx_ring, int napi_budget)
> +			      struct i40e_ring *tx_ring, int napi_budget,
> +			      unsigned int *tx_cleaned)
>   {
>   	int i = tx_ring->next_to_clean;
>   	struct i40e_tx_buffer *tx_buf;
> @@ -1026,7 +1028,7 @@ static bool i40e_clean_tx_irq(struct i40e_vsi *vsi,
>   	i40e_arm_wb(tx_ring, vsi, budget);
>   
>   	if (ring_is_xdp(tx_ring))
> -		return !!budget;
> +		goto out;
>   
>   	/* notify netdev of completed buffers */
>   	netdev_tx_completed_queue(txring_txq(tx_ring),
> @@ -1048,6 +1050,8 @@ static bool i40e_clean_tx_irq(struct i40e_vsi *vsi,
>   		}
>   	}
>   
> +out:
> +	*tx_cleaned = total_packets;
>   	return !!budget;
>   }
>   
> @@ -2689,10 +2693,12 @@ int i40e_napi_poll(struct napi_struct *napi, int budget)
>   			       container_of(napi, struct i40e_q_vector, napi);
>   	struct i40e_vsi *vsi = q_vector->vsi;
>   	struct i40e_ring *ring;
> +	bool tx_clean_complete = true;
>   	bool clean_complete = true;
>   	bool arm_wb = false;
>   	int budget_per_ring;
>   	int work_done = 0;
> +	unsigned int tx_cleaned = 0;
>   
>   	if (test_bit(__I40E_VSI_DOWN, vsi->state)) {
>   		napi_complete(napi);
> @@ -2704,11 +2710,11 @@ int i40e_napi_poll(struct napi_struct *napi, int budget)
>   	 */
>   	i40e_for_each_ring(ring, q_vector->tx) {
>   		bool wd = ring->xsk_pool ?
> -			  i40e_clean_xdp_tx_irq(vsi, ring) :
> -			  i40e_clean_tx_irq(vsi, ring, budget);
> +			  i40e_clean_xdp_tx_irq(vsi, ring, &tx_cleaned) :
> +			  i40e_clean_tx_irq(vsi, ring, budget, &tx_cleaned);
>   
>   		if (!wd) {
> -			clean_complete = false;
> +			clean_complete = tx_clean_complete = false;
>   			continue;
>   		}
>   		arm_wb |= ring->arm_wb;
> diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.c b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
> index 790aaeff..f98ce7e4 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c
> +++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
> @@ -530,18 +530,22 @@ static void i40e_set_rs_bit(struct i40e_ring *xdp_ring)
>    * i40e_xmit_zc - Performs zero-copy Tx AF_XDP
>    * @xdp_ring: XDP Tx ring
>    * @budget: NAPI budget
> + * @tx_cleaned: Out parameter of the TX packets processed
>    *
>    * Returns true if the work is finished.
>    **/
> -static bool i40e_xmit_zc(struct i40e_ring *xdp_ring, unsigned int budget)
> +static bool i40e_xmit_zc(struct i40e_ring *xdp_ring, unsigned int budget,
> +			 unsigned int *tx_cleaned)
>   {
>   	struct xdp_desc *descs = xdp_ring->xsk_pool->tx_descs;
>   	u32 nb_pkts, nb_processed = 0;
>   	unsigned int total_bytes = 0;
>   
>   	nb_pkts = xsk_tx_peek_release_desc_batch(xdp_ring->xsk_pool, budget);
> -	if (!nb_pkts)
> +	if (!nb_pkts) {
> +		*tx_cleaned = 0;
>   		return true;
> +	}
>   
>   	if (xdp_ring->next_to_use + nb_pkts >= xdp_ring->count) {
>   		nb_processed = xdp_ring->count - xdp_ring->next_to_use;
> @@ -558,6 +562,7 @@ static bool i40e_xmit_zc(struct i40e_ring *xdp_ring, unsigned int budget)
>   
>   	i40e_update_tx_stats(xdp_ring, nb_pkts, total_bytes);
>   
> +	*tx_cleaned = nb_pkts;

With XDP, I don't think we should count these as tx_cleaned packets. These are transmitted
packets. The tx_cleaned would be the xsk_frames counter in i40e_clean_xdp_tx_irq
May be we need 2 counters for xdp.


>   	return nb_pkts < budget;
>   }
>   
> @@ -581,10 +586,12 @@ static void i40e_clean_xdp_tx_buffer(struct i40e_ring *tx_ring,
>    * i40e_clean_xdp_tx_irq - Completes AF_XDP entries, and cleans XDP entries
>    * @vsi: Current VSI
>    * @tx_ring: XDP Tx ring
> + * @tx_cleaned: out parameter of number of TXes cleaned
>    *
>    * Returns true if cleanup/tranmission is done.
>    **/
> -bool i40e_clean_xdp_tx_irq(struct i40e_vsi *vsi, struct i40e_ring *tx_ring)
> +bool i40e_clean_xdp_tx_irq(struct i40e_vsi *vsi, struct i40e_ring *tx_ring,
> +			   unsigned int *tx_cleaned)
>   {
>   	struct xsk_buff_pool *bp = tx_ring->xsk_pool;
>   	u32 i, completed_frames, xsk_frames = 0;
> @@ -634,7 +641,7 @@ bool i40e_clean_xdp_tx_irq(struct i40e_vsi *vsi, struct i40e_ring *tx_ring)
>   	if (xsk_uses_need_wakeup(tx_ring->xsk_pool))
>   		xsk_set_tx_need_wakeup(tx_ring->xsk_pool);
>   
> -	return i40e_xmit_zc(tx_ring, I40E_DESC_UNUSED(tx_ring));
> +	return i40e_xmit_zc(tx_ring, I40E_DESC_UNUSED(tx_ring), tx_cleaned);
>   }
>   
>   /**
> diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.h b/drivers/net/ethernet/intel/i40e/i40e_xsk.h
> index 821df24..396ed11 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_xsk.h
> +++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.h
> @@ -30,7 +30,8 @@ int i40e_xsk_pool_setup(struct i40e_vsi *vsi, struct xsk_buff_pool *pool,
>   bool i40e_alloc_rx_buffers_zc(struct i40e_ring *rx_ring, u16 cleaned_count);
>   int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, int budget);
>   
> -bool i40e_clean_xdp_tx_irq(struct i40e_vsi *vsi, struct i40e_ring *tx_ring);
> +bool i40e_clean_xdp_tx_irq(struct i40e_vsi *vsi, struct i40e_ring *tx_ring,
> +			   unsigned int *tx_cleaned);
>   int i40e_xsk_wakeup(struct net_device *dev, u32 queue_id, u32 flags);
>   int i40e_realloc_rx_bi_zc(struct i40e_vsi *vsi, bool zc);
>   void i40e_clear_rx_bi_zc(struct i40e_ring *rx_ring);