Subject: Re: [PATCH net-next v4 6/6] sfc: add XDP counters to ethtool stats

From: Jesper Dangaard Brouer <[email-masked]>
Date: Thu, 31 Oct 2019 21:13:00 +0100

On Thu, 31 Oct 2019 10:24:23 +0000
Charles McLachlan <[email-masked]> wrote:

> Count XDP packet drops, error drops, transmissions and redirects and
> expose these counters via the ethtool stats command.
> 
> Signed-off-by: Charles McLachlan <[email-masked]>

I'm going to ACK this even-though I don't like these driver specific
counters.  Given we have failed to standardize this, I really cannot
complain.  Hopefully we will get this standardized later

Acked-by: Jesper Dangaard Brouer <[email-masked]>

Left code below, if Ahern want to complain ;-)

>  drivers/net/ethernet/sfc/ethtool.c    | 25 +++++++++++++++++++++++++
>  drivers/net/ethernet/sfc/net_driver.h |  8 ++++++++
>  drivers/net/ethernet/sfc/rx.c         |  9 +++++++++
>  3 files changed, 42 insertions(+)
> 
> diff --git a/drivers/net/ethernet/sfc/ethtool.c b/drivers/net/ethernet/sfc/ethtool.c
> index 86b965875540..8db593fb9699 100644
> --- a/drivers/net/ethernet/sfc/ethtool.c
> +++ b/drivers/net/ethernet/sfc/ethtool.c
> @@ -83,6 +83,10 @@ static const struct efx_sw_stat_desc efx_sw_stat_desc[] = {
>  	EFX_ETHTOOL_UINT_CHANNEL_STAT(rx_frm_trunc),
>  	EFX_ETHTOOL_UINT_CHANNEL_STAT(rx_merge_events),
>  	EFX_ETHTOOL_UINT_CHANNEL_STAT(rx_merge_packets),
> +	EFX_ETHTOOL_UINT_CHANNEL_STAT(rx_xdp_drops),
> +	EFX_ETHTOOL_UINT_CHANNEL_STAT(rx_xdp_bad_drops),
> +	EFX_ETHTOOL_UINT_CHANNEL_STAT(rx_xdp_tx),
> +	EFX_ETHTOOL_UINT_CHANNEL_STAT(rx_xdp_redirect),
>  };
>  
>  #define EFX_ETHTOOL_SW_STAT_COUNT ARRAY_SIZE(efx_sw_stat_desc)
> @@ -399,6 +403,19 @@ static size_t efx_describe_per_queue_stats(struct efx_nic *efx, u8 *strings)
>  			}
>  		}
>  	}
> +	if (efx->xdp_tx_queue_count && efx->xdp_tx_queues) {
> +		unsigned short xdp;
> +
> +		for (xdp = 0; xdp < efx->xdp_tx_queue_count; xdp++) {
> +			n_stats++;
> +			if (strings) {
> +				snprintf(strings, ETH_GSTRING_LEN,
> +					 "tx-xdp-cpu-%hu.tx_packets", xdp);
> +				strings += ETH_GSTRING_LEN;
> +			}
> +		}
> +	}
> +
>  	return n_stats;
>  }
>  
> @@ -509,6 +526,14 @@ static void efx_ethtool_get_stats(struct net_device *net_dev,
>  			data++;
>  		}
>  	}
> +	if (efx->xdp_tx_queue_count && efx->xdp_tx_queues) {
> +		int xdp;
> +
> +		for (xdp = 0; xdp < efx->xdp_tx_queue_count; xdp++) {
> +			data[0] = efx->xdp_tx_queues[xdp]->tx_packets;
> +			data++;
> +		}
> +	}
>  
>  	efx_ptp_update_stats(efx, data);
>  }
> diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h
> index 505ddc060e64..04e49eac7327 100644
> --- a/drivers/net/ethernet/sfc/net_driver.h
> +++ b/drivers/net/ethernet/sfc/net_driver.h
> @@ -453,6 +453,10 @@ enum efx_sync_events_state {
>   *	lack of descriptors
>   * @n_rx_merge_events: Number of RX merged completion events
>   * @n_rx_merge_packets: Number of RX packets completed by merged events
> + * @n_rx_xdp_drops: Count of RX packets intentionally dropped due to XDP
> + * @n_rx_xdp_bad_drops: Count of RX packets dropped due to XDP errors
> + * @n_rx_xdp_tx: Count of RX packets retransmitted due to XDP
> + * @n_rx_xdp_redirect: Count of RX packets redirected to a different NIC by XDP
>   * @rx_pkt_n_frags: Number of fragments in next packet to be delivered by
>   *	__efx_rx_packet(), or zero if there is none
>   * @rx_pkt_index: Ring index of first buffer for next packet to be delivered
> @@ -506,6 +510,10 @@ struct efx_channel {
>  	unsigned int n_rx_nodesc_trunc;
>  	unsigned int n_rx_merge_events;
>  	unsigned int n_rx_merge_packets;
> +	unsigned int n_rx_xdp_drops;
> +	unsigned int n_rx_xdp_bad_drops;
> +	unsigned int n_rx_xdp_tx;
> +	unsigned int n_rx_xdp_redirect;
>  
>  	unsigned int rx_pkt_n_frags;
>  	unsigned int rx_pkt_index;
> diff --git a/drivers/net/ethernet/sfc/rx.c b/drivers/net/ethernet/sfc/rx.c
> index 91f6d5b9ceac..a7d9841105d8 100644
> --- a/drivers/net/ethernet/sfc/rx.c
> +++ b/drivers/net/ethernet/sfc/rx.c
> @@ -677,6 +677,7 @@ static bool efx_do_xdp(struct efx_nic *efx, struct efx_channel *channel,
>  			netif_err(efx, rx_err, efx->net_dev,
>  				  "XDP is not possible with multiple receive fragments (%d)\n",
>  				  channel->rx_pkt_n_frags);
> +		channel->n_rx_xdp_bad_drops++;
>  		return false;
>  	}
>  
> @@ -722,6 +723,9 @@ static bool efx_do_xdp(struct efx_nic *efx, struct efx_channel *channel,
>  			if (net_ratelimit())
>  				netif_err(efx, rx_err, efx->net_dev,
>  					  "XDP TX failed (%d)\n", err);
> +			channel->n_rx_xdp_bad_drops++;
> +		} else {
> +			channel->n_rx_xdp_tx++;
>  		}
>  		break;
>  
> @@ -732,12 +736,16 @@ static bool efx_do_xdp(struct efx_nic *efx, struct efx_channel *channel,
>  			if (net_ratelimit())
>  				netif_err(efx, rx_err, efx->net_dev,
>  					  "XDP redirect failed (%d)\n", err);
> +			channel->n_rx_xdp_bad_drops++;
> +		} else {
> +			channel->n_rx_xdp_redirect++;
>  		}
>  		break;
>  
>  	default:
>  		bpf_warn_invalid_xdp_action(xdp_act);
>  		efx_free_rx_buffers(rx_queue, rx_buf, 1);
> +		channel->n_rx_xdp_bad_drops++;
>  		break;
>  
>  	case XDP_ABORTED:
> @@ -745,6 +753,7 @@ static bool efx_do_xdp(struct efx_nic *efx, struct efx_channel *channel,
>  		/* Fall through */
>  	case XDP_DROP:
>  		efx_free_rx_buffers(rx_queue, rx_buf, 1);
> +		channel->n_rx_xdp_drops++;
>  		break;
>  	}
>  

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer