linux-kernel - Re: [PATCH] net: ethernet: ti: cpsw_ale: optimize cpsw_ale

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Date:   Wed, 9 Nov 2022 19:19:41 -0800
From:   Jakub Kicinski <kuba@...nel.org>
To:     Roger Quadros <rogerq@...nel.org>
Cc:     davem@...emloft.net, edumazet@...gle.com, pabeni@...hat.com,
        vigneshr@...com, srk@...com, linux-omap@...r.kernel.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] net: ethernet: ti: cpsw_ale: optimize
 cpsw_ale_restore()

On Tue,  8 Nov 2022 15:56:43 +0200 Roger Quadros wrote:
> If an entry was FREE then we don't have to restore it.

Motivation? Does it make the restore faster?

> Signed-off-by: Roger Quadros <rogerq@...nel.org>
> ---
> 
> Patch depends on
> https://lore.kernel.org/netdev/20221104132310.31577-3-rogerq@kernel.org/T/
> 
>  drivers/net/ethernet/ti/cpsw_ale.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/ti/cpsw_ale.c b/drivers/net/ethernet/ti/cpsw_ale.c
> index 0c5e783e574c..41bcf34a22f8 100644
> --- a/drivers/net/ethernet/ti/cpsw_ale.c
> +++ b/drivers/net/ethernet/ti/cpsw_ale.c
> @@ -1452,12 +1452,15 @@ void cpsw_ale_dump(struct cpsw_ale *ale, u32 *data)
>  	}
>  }
>  
> +/* ALE table should be cleared (ALE_CLEAR) before cpsw_ale_restore() */

Maybe my tree is old but I see we clear only if there is a netdev that
needs to be opened but then always call ale_restore(). Is that okay?

I'd also s/should/must/ 

>  void cpsw_ale_restore(struct cpsw_ale *ale, u32 *data)
>  {
> -	int i;
> +	int i, type;
>  
>  	for (i = 0; i < ale->params.ale_entries; i++) {
> -		cpsw_ale_write(ale, i, data);
> +		type = cpsw_ale_get_entry_type(data);
> +		if (type != ALE_TYPE_FREE)
> +			cpsw_ale_write(ale, i, data);
>  		data += ALE_ENTRY_WORDS;
>  	}
>  }