Re: [dpdk-dev] [PATCH] i40e: workaround for XL710 performance

[Neil Horman <nhorman@tuxdriver.com>]

On Wed, Dec 24, 2014 at 03:14:08PM +0800, Helin Zhang wrote:
> on XL710, performance number is far from the expectation on recent
> firmware versions, if promiscuous mode is disabled, or promiscuous
> mode is enabled and port MAC address is equal to the packet
> destination MAC address. The fix for this issue may not be integrated
> in the following firmware version. So the workaround in software
> driver is needed. It needs to modify the initial values of 2 internal
> only registers which is the same 2 of 3 registers of it did for X710.
> Note that the workaround can be removed when it is fixed in firmware
> in the future.
> 
> Signed-off-by: Helin Zhang <helin.zhang@intel.com>
> ---
>  lib/librte_pmd_i40e/i40e_ethdev.c | 35 ++++++++++++++++++++++-------------
>  1 file changed, 22 insertions(+), 13 deletions(-)
> 
> diff --git a/lib/librte_pmd_i40e/i40e_ethdev.c b/lib/librte_pmd_i40e/i40e_ethdev.c
> index b47a3d2..3bb75d8 100644
> --- a/lib/librte_pmd_i40e/i40e_ethdev.c
> +++ b/lib/librte_pmd_i40e/i40e_ethdev.c
> @@ -5327,21 +5327,30 @@ i40e_debug_read_register(struct i40e_hw *hw, uint32_t addr, uint64_t *val)
>  
>  /*
>   * On X710, performance number is far from the expectation on recent firmware
> - * versions. The fix for this issue may not be integrated in the following
> + * versions; on XL710, performance number is also far from the expectation on
> + * recent firmware versions, if promiscuous mode is disabled, or promiscuous
> + * mode is enabled and port MAC address is equal to the packet destination MAC
> + * address. The fix for this issue may not be integrated in the following
>   * firmware version. So the workaround in software driver is needed. It needs
> - * to modify the initial values of 3 internal only registers. Note that the
> - * workaround can be removed when it is fixed in firmware in the future.
> + * to modify the initial values of 3 internal only registers for X710, and the
> + * same 2 internal registers for XL710. Note that the workaround can be removed
> + * when it is fixed in firmware in the future.

Wouldn't it be preferable to add a firmware version check to this code so that a
single driver can handle both cards with old and 'fixed' firmware?  That way
nothing needs to be removed and all i40e cards will have a consistent behavior
Neil

>   */
> -static void
> -i40e_configure_registers(struct i40e_hw *hw)
> -{
> -#define I40E_GL_SWR_PRI_JOIN_MAP_0       0x26CE00
> -#define I40E_GL_SWR_PRI_JOIN_MAP_2       0x26CE08
> -#define I40E_GL_SWR_PM_UP_THR            0x269FBC
> +
> +/* For both X710 and XL710 */
>  #define I40E_GL_SWR_PRI_JOIN_MAP_0_VALUE 0x10000200
> +#define I40E_GL_SWR_PRI_JOIN_MAP_0       0x26CE00
> +
>  #define I40E_GL_SWR_PRI_JOIN_MAP_2_VALUE 0x011f0200
> +#define I40E_GL_SWR_PRI_JOIN_MAP_2       0x26CE08
> +
> +/* For X710 only */
>  #define I40E_GL_SWR_PM_UP_THR_VALUE      0x03030303
> +#define I40E_GL_SWR_PM_UP_THR            0x269FBC
>  
> +static void
> +i40e_configure_registers(struct i40e_hw *hw)
> +{
>  	static const struct {
>  		uint32_t addr;
>  		uint64_t val;
> @@ -5354,11 +5363,11 @@ i40e_configure_registers(struct i40e_hw *hw)
>  	uint32_t i;
>  	int ret;
>  
> -	/* Below fix is for X710 only */
> -	if (i40e_is_40G_device(hw->device_id))
> -		return;
> -
>  	for (i = 0; i < RTE_DIM(reg_table); i++) {
> +		if ((i40e_is_40G_device(hw->device_id)) &&
> +			(reg_table[i].addr == I40E_GL_SWR_PM_UP_THR))
> +			continue;
> +
>  		ret = i40e_debug_read_register(hw, reg_table[i].addr, &reg);
>  		if (ret < 0) {
>  			PMD_DRV_LOG(ERR, "Failed to read from 0x%"PRIx32,
> -- 
> 1.9.3
> 
>