Re: [dpdk-dev] [PATCH] net/i40e: i40e FDIR update rate optimization

["Wang, Haiyue" <haiyue.wang@intel.com>]

> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of chenmin.sun@intel.com
> Sent: Saturday, June 13, 2020 02:00
> To: Zhang, Qi Z <qi.z.zhang@intel.com>; Xing, Beilei <beilei.xing@intel.com>; Wu, Jingjing
> <jingjing.wu@intel.com>
> Cc: dev@dpdk.org; Sun, Chenmin <chenmin.sun@intel.com>
> Subject: [dpdk-dev] [PATCH] net/i40e: i40e FDIR update rate optimization
> 
> From: Chenmin Sun <chenmin.sun@intel.com>
> 
> This patch optimized the fdir update rate for i40e PF, by tracking the
> fdir rule will be inserted into guaranteed space or shared space.
> For the flows that are inserted to the guaranteed space, it returns success
> directly without retrieving the result for NIC.
> 
> This patch changes the global register GLQF_CTL. Therefore, when devarg
> ``Support multiple driver`` is set, the patch will not take effect to
> avoid affecting the normal behavior of other i40e drivers, e.g., Linux
> kernel driver.
> 
> Signed-off-by: Chenmin Sun <chenmin.sun@intel.com>
> ---
>  drivers/net/i40e/i40e_ethdev.c  |  96 ++++++++++++++++-
>  drivers/net/i40e/i40e_ethdev.h  |  57 +++++++---
>  drivers/net/i40e/i40e_fdir.c    | 182 +++++++++++++++++++++-----------
>  drivers/net/i40e/i40e_flow.c    | 181 +++++++++++++++++++++++++------
>  drivers/net/i40e/i40e_rxtx.c    |  15 ++-
>  drivers/net/i40e/rte_pmd_i40e.c |   2 +-
>  6 files changed, 417 insertions(+), 116 deletions(-)
> 


> 
> +static
> +uint32_t bin_search(uint64_t data)
> +{
> +	uint32_t pos = 0;
> +
> +	if ((data & 0xFFFFFFFF) == 0) {
> +		data >>= 32;
> +		pos += 32;
> +	}
> +
> +	if ((data & 0xFFFF) == 0) {
> +		data >>= 16;
> +		pos += 16;
> +	}
> +	if ((data & 0xFF) == 0) {
> +		data >>= 8;
> +		pos += 8;
> +	}
> +	if ((data & 0xF) == 0) {
> +		data >>= 4;
> +		pos += 4;
> +	}
> +	if ((data & 0x3) == 0) {
> +		data >>= 2;
> +		pos += 2;
> +	}
> +	if ((data & 0x1) == 0)
> +		pos += 1;
> +
> +	return pos;
> +}
> +

Try " __builtin_ctzll ", DPDK has many examples to use it. ;-)

> --
> 2.17.1