net/i40e: fix statistics

  From: Chenmin Sun <chenmin.sun@intel.com>

1. Fix the lldp stop condition check - for firmware
versions 6.01(for X710)/3.33(for X722) or later we need stop the lldp
2. Doucment known issue for tx bytes decreasing due to link status chage

Fixes: 044846f071cc ("net/i40e: stop LLDP before setting local LLDP MIB")
Cc: stable@dpdk.org
Cc: qi.z.zhang@intel.com

Signed-off-by: Chenmin Sun <chenmin.sun@intel.com>
---
 doc/guides/nics/i40e.rst       |  7 +++++++
 drivers/net/i40e/i40e_ethdev.c | 38 +++++++++++++++++++++++++++-------
 2 files changed, 37 insertions(+), 8 deletions(-)
  

> -----Original Message-----
> From: Sun, Chenmin
> Sent: Wednesday, January 23, 2019 9:30 PM
> To: dev@dpdk.org
> Cc: stable@dpdk.org; Sun, Chenmin <chenmin.sun@intel.com>; Zhang, Qi Z
> <qi.z.zhang@intel.com>
> Subject: [PATCH] net/i40e: fix statistics
> 
> From: Chenmin Sun <chenmin.sun@intel.com>
> 
> 1. Fix the lldp stop condition check - for firmware versions 6.01(for X710)/3.33(for
> X722) or later we need stop the lldp 2. Doucment known issue for tx bytes
> decreasing due to link status chage

s/Doucment/Document
s/chage/change

Also add
3. deferred stats reset in dev_init to avoid some noise be counted.

> 
> Fixes: 044846f071cc ("net/i40e: stop LLDP before setting local LLDP MIB")
> Cc: stable@dpdk.org
> Cc: qi.z.zhang@intel.com
> 
> Signed-off-by: Chenmin Sun <chenmin.sun@intel.com>

Acked-by: Qi Zhang <qi.z.zhang@intel.com>

Applied into dpdk-next-net-intel with above commit log change and below minor fix.

Thanks
Qi
> ---
>  doc/guides/nics/i40e.rst       |  7 +++++++
>  drivers/net/i40e/i40e_ethdev.c | 38 +++++++++++++++++++++++++++-------
>  2 files changed, 37 insertions(+), 8 deletions(-)
> 
> diff --git a/doc/guides/nics/i40e.rst b/doc/guides/nics/i40e.rst index
> 6aceb53ea..d9ec07e12 100644
> --- a/doc/guides/nics/i40e.rst
> +++ b/doc/guides/nics/i40e.rst
> @@ -698,3 +698,10 @@ See :numref:`figure_intel_perf_test_setup` for the
> performance test setup.
>     * Start creating a stream on packet generator.
> 
>     * Set the Ethernet II type to 0x0800.
> +
> +Tx bytes affected by the link status change
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +For firmware versions prior to 6.01 for X710 series and 3.33 for X722
> +series, the tx_bytes statsistics data is affected by the link down event. Each

s/statsistics/statistics

> time the link status changes to down, the tx_bytes decreases 110 bytes.
> +

Empty line at end of file

> diff --git a/drivers/net/i40e/i40e_ethdev.c b/drivers/net/i40e/i40e_ethdev.c
> index a6b97e164..181efbac0 100644
> --- a/drivers/net/i40e/i40e_ethdev.c
> +++ b/drivers/net/i40e/i40e_ethdev.c
> @@ -1493,9 +1493,6 @@ eth_i40e_dev_init(struct rte_eth_dev *dev, void
> *init_params __rte_unused)
>  		goto err_setup_pf_switch;
>  	}
> 
> -	/* reset all stats of the device, including pf and main vsi */
> -	i40e_dev_stats_reset(dev);
> -
>  	vsi = pf->main_vsi;
> 
>  	/* Disable double vlan by default */
> @@ -1590,6 +1587,9 @@ eth_i40e_dev_init(struct rte_eth_dev *dev, void
> *init_params __rte_unused)
>  	memset(&pf->rss_info, 0,
>  		sizeof(struct i40e_rte_flow_rss_conf));
> 
> +	/* reset all stats of the device, including pf and main vsi */
> +	i40e_dev_stats_reset(dev);
> +
>  	return 0;
> 
>  err_init_fdir_filter_list:
> @@ -3454,12 +3454,38 @@ i40e_fw_version_get(struct rte_eth_dev *dev, char
> *fw_version, size_t fw_size)
>  		 ver, build, patch);
> 
>  	ret += 1; /* add the size of '\0' */
> +

Unnecessary change.

>  	if (fw_size < (u32)ret)
>  		return ret;
>  	else
>  		return 0;
>  }
> 
> +/*
> + * When using NVM 6.01(for X710 XL710 XXV710)/3.33(for X722) or later,
> + * the Rx data path does not hang if the FW LLDP is stopped.
> + * return true if lldp need to stop
> + * return false if we cannot disable the LLDP to avoid Rx data path blocking.
> + */
> +static bool
> +i40e_need_stop_lldp(struct rte_eth_dev *dev) {
> +	double nvm_ver;
> +	char ver_str[64] = {0};
> +	struct i40e_hw *hw =
> I40E_DEV_PRIVATE_TO_HW(dev->data->dev_private);
> +
> +	i40e_fw_version_get(dev, ver_str, 64);
> +	nvm_ver = atof(ver_str);
> +	if ((hw->mac.type == I40E_MAC_X722 ||
> +	     hw->mac.type == I40E_MAC_X722_VF) &&
> +	     ((uint32_t)(nvm_ver * 1000) >= (uint32_t)(3.33 * 1000)))
> +		return true;
> +	else if ((uint32_t)(nvm_ver * 1000) >= (uint32_t)(6.01 * 1000))
> +		return true;
> +
> +	return false;
> +}
> +
>  static void
>  i40e_dev_info_get(struct rte_eth_dev *dev, struct rte_eth_dev_info
> *dev_info)  { @@ -11425,11 +11451,7 @@ i40e_dcb_init_configure(struct
> rte_eth_dev *dev, bool sw_dcb)
>  	 * LLDP MIB change event.
>  	 */
>  	if (sw_dcb == TRUE) {
> -		/* When using NVM 6.01 or later, the RX data path does
> -		 * not hang if the FW LLDP is stopped.
> -		 */
> -		if (((hw->nvm.version >> 12) & 0xf) >= 6 &&
> -		    ((hw->nvm.version >> 4) & 0xff) >= 1) {
> +		if (i40e_need_stop_lldp(dev)) {
>  			ret = i40e_aq_stop_lldp(hw, TRUE, NULL);
>  			if (ret != I40E_SUCCESS)
>  				PMD_INIT_LOG(DEBUG, "Failed to stop lldp");
> --
> 2.17.1