linux-kernel - Re: [PATCH v6 net-next 2/5] net: mscc: ocelot: remove unnecessary stat reading from ethtool

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Date:   Thu, 10 Feb 2022 10:34:47 +0000
From:   Vladimir Oltean <vladimir.oltean@....com>
To:     Colin Foster <colin.foster@...advantage.com>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        Jakub Kicinski <kuba@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        "UNGLinuxDriver@...rochip.com" <UNGLinuxDriver@...rochip.com>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Claudiu Manoil <claudiu.manoil@....com>
Subject: Re: [PATCH v6 net-next 2/5] net: mscc: ocelot: remove unnecessary
 stat reading from ethtool

On Wed, Feb 09, 2022 at 08:13:42PM -0800, Colin Foster wrote:
> The ocelot_update_stats function only needs to read from one port, yet it
> was updating the stats for all ports. Update to only read the stats that
> are necessary.
> 
> Signed-off-by: Colin Foster <colin.foster@...advantage.com>
> ---

Reviewed-by: Vladimir Oltean <vladimir.oltean@....com>

>  drivers/net/ethernet/mscc/ocelot.c | 33 +++++++++++++++---------------
>  1 file changed, 16 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
> index 6933dff1dd37..ab36732e7d3f 100644
> --- a/drivers/net/ethernet/mscc/ocelot.c
> +++ b/drivers/net/ethernet/mscc/ocelot.c
> @@ -1738,27 +1738,24 @@ void ocelot_get_strings(struct ocelot *ocelot, int port, u32 sset, u8 *data)
>  EXPORT_SYMBOL(ocelot_get_strings);
>  
>  /* Caller must hold &ocelot->stats_lock */
> -static void ocelot_update_stats(struct ocelot *ocelot)
> +static void ocelot_update_stats_for_port(struct ocelot *ocelot, int port)

If you need to resend, I think a name more consistent with the rest of
the driver would be "ocelot_port_update_stats".

>  {
> -	int i, j;
> +	int j;
>  
> -	for (i = 0; i < ocelot->num_phys_ports; i++) {
> -		/* Configure the port to read the stats from */
> -		ocelot_write(ocelot, SYS_STAT_CFG_STAT_VIEW(i), SYS_STAT_CFG);
> +	/* Configure the port to read the stats from */
> +	ocelot_write(ocelot, SYS_STAT_CFG_STAT_VIEW(port), SYS_STAT_CFG);
>  
> -		for (j = 0; j < ocelot->num_stats; j++) {
> -			u32 val;
> -			unsigned int idx = i * ocelot->num_stats + j;
> +	for (j = 0; j < ocelot->num_stats; j++) {
> +		u32 val;
> +		unsigned int idx = port * ocelot->num_stats + j;
>  
> -			val = ocelot_read_rix(ocelot, SYS_COUNT_RX_OCTETS,
> -					      ocelot->stats_layout[j].offset);
> +		val = ocelot_read_rix(ocelot, SYS_COUNT_RX_OCTETS,
> +				      ocelot->stats_layout[j].offset);
>  
> -			if (val < (ocelot->stats[idx] & U32_MAX))
> -				ocelot->stats[idx] += (u64)1 << 32;
> +		if (val < (ocelot->stats[idx] & U32_MAX))
> +			ocelot->stats[idx] += (u64)1 << 32;
>  
> -			ocelot->stats[idx] = (ocelot->stats[idx] &
> -					      ~(u64)U32_MAX) + val;
> -		}
> +		ocelot->stats[idx] = (ocelot->stats[idx] & ~(u64)U32_MAX) + val;
>  	}
>  }
>  
> @@ -1767,9 +1764,11 @@ static void ocelot_check_stats_work(struct work_struct *work)
>  	struct delayed_work *del_work = to_delayed_work(work);
>  	struct ocelot *ocelot = container_of(del_work, struct ocelot,
>  					     stats_work);
> +	int i;
>  
>  	mutex_lock(&ocelot->stats_lock);
> -	ocelot_update_stats(ocelot);
> +	for (i = 0; i < ocelot->num_phys_ports; i++)
> +		ocelot_update_stats_for_port(ocelot, i);
>  	mutex_unlock(&ocelot->stats_lock);
>  
>  	queue_delayed_work(ocelot->stats_queue, &ocelot->stats_work,
> @@ -1783,7 +1782,7 @@ void ocelot_get_ethtool_stats(struct ocelot *ocelot, int port, u64 *data)
>  	mutex_lock(&ocelot->stats_lock);
>  
>  	/* check and update now */
> -	ocelot_update_stats(ocelot);
> +	ocelot_update_stats_for_port(ocelot, port);
>  
>  	/* Copy all counters */
>  	for (i = 0; i < ocelot->num_stats; i++)
> -- 
> 2.25.1
>