Subject: Re: [PATCH 7/7]: [NET]: Make ->poll() breakout consistent in Intel ethernet drivers.

From: "Kok, Auke" <[email-masked]>
Date: Tue, 08 Jan 2008 11:04:59 -0800

David Miller wrote:
> [NET]: Make ->poll() breakout consistent in Intel ethernet drivers.
> 
> This makes the ->poll() routines of the E100, E1000, E1000E, IXGB, and
> IXGBE drivers complete ->poll() consistently.
> 
> Now they will all break out when the amount of RX work done is less
> than 'budget'.
> 
> At a later time, we may want put back code to include the TX work as
> well (as at least one other NAPI driver does, but by in large NAPI
> drivers do not do this).  But if so, it should be done consistently
> across the board to all of these drivers.
> 
> Signed-off-by: David S. Miller <[email-masked]>

this is exactly the change I was eyeballing and indeed this seems to be the
general use case in most drivers anyway.

I'll try to see how this impacts the (especially 4-port) TX performance issue with
e1000e, but this should be just fine for now, and we can address later anyway.

Acked-by: Auke Kok <[email-masked]>

Auke

> ---
>  drivers/net/e100.c             |    7 +++----
>  drivers/net/e1000/e1000_main.c |   10 +++++-----
>  drivers/net/e1000e/netdev.c    |    8 ++++----
>  drivers/net/ixgb/ixgb_main.c   |    7 +++----
>  drivers/net/ixgbe/ixgbe_main.c |    8 ++++----
>  5 files changed, 19 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/net/e100.c b/drivers/net/e100.c
> index 68316f1..b87402b 100644
> --- a/drivers/net/e100.c
> +++ b/drivers/net/e100.c
> @@ -1991,13 +1991,12 @@ static int e100_poll(struct napi_struct *napi, int budget)
>  	struct nic *nic = container_of(napi, struct nic, napi);
>  	struct net_device *netdev = nic->netdev;
>  	unsigned int work_done = 0;
> -	int tx_cleaned;
>  
>  	e100_rx_clean(nic, &work_done, budget);
> -	tx_cleaned = e100_tx_clean(nic);
> +	e100_tx_clean(nic);
>  
> -	/* If no Rx and Tx cleanup work was done, exit polling mode. */
> -	if((!tx_cleaned && (work_done == 0))) {
> +	/* If budget not fully consumed, exit the polling mode */
> +	if (work_done < budget) {
>  		netif_rx_complete(netdev, napi);
>  		e100_enable_irq(nic);
>  	}
> diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c
> index 9de7144..13d57b0 100644
> --- a/drivers/net/e1000/e1000_main.c
> +++ b/drivers/net/e1000/e1000_main.c
> @@ -3919,7 +3919,7 @@ e1000_clean(struct napi_struct *napi, int budget)
>  {
>  	struct e1000_adapter *adapter = container_of(napi, struct e1000_adapter, napi);
>  	struct net_device *poll_dev = adapter->netdev;
> -	int tx_cleaned = 0, work_done = 0;
> +	int work_done = 0;
>  
>  	/* Must NOT use netdev_priv macro here. */
>  	adapter = poll_dev->priv;
> @@ -3929,16 +3929,16 @@ e1000_clean(struct napi_struct *napi, int budget)
>  	 * simultaneously.  A failure obtaining the lock means
>  	 * tx_ring[0] is currently being cleaned anyway. */
>  	if (spin_trylock(&adapter->tx_queue_lock)) {
> -		tx_cleaned = e1000_clean_tx_irq(adapter,
> -		                                &adapter->tx_ring[0]);
> +		e1000_clean_tx_irq(adapter,
> +				   &adapter->tx_ring[0]);
>  		spin_unlock(&adapter->tx_queue_lock);
>  	}
>  
>  	adapter->clean_rx(adapter, &adapter->rx_ring[0],
>  	                  &work_done, budget);
>  
> -	/* If no Tx and not enough Rx work done, exit the polling mode */
> -	if ((!tx_cleaned && (work_done == 0))) {
> +	/* If budget not fully consumed, exit the polling mode */
> +	if (work_done < budget) {
>  		if (likely(adapter->itr_setting & 3))
>  			e1000_set_itr(adapter);
>  		netif_rx_complete(poll_dev, napi);
> diff --git a/drivers/net/e1000e/netdev.c b/drivers/net/e1000e/netdev.c
> index dd9698c..4a6fc74 100644
> --- a/drivers/net/e1000e/netdev.c
> +++ b/drivers/net/e1000e/netdev.c
> @@ -1384,7 +1384,7 @@ static int e1000_clean(struct napi_struct *napi, int budget)
>  {
>  	struct e1000_adapter *adapter = container_of(napi, struct e1000_adapter, napi);
>  	struct net_device *poll_dev = adapter->netdev;
> -	int tx_cleaned = 0, work_done = 0;
> +	int work_done = 0;
>  
>  	/* Must NOT use netdev_priv macro here. */
>  	adapter = poll_dev->priv;
> @@ -1394,14 +1394,14 @@ static int e1000_clean(struct napi_struct *napi, int budget)
>  	 * simultaneously.  A failure obtaining the lock means
>  	 * tx_ring is currently being cleaned anyway. */
>  	if (spin_trylock(&adapter->tx_queue_lock)) {
> -		tx_cleaned = e1000_clean_tx_irq(adapter);
> +		e1000_clean_tx_irq(adapter);
>  		spin_unlock(&adapter->tx_queue_lock);
>  	}
>  
>  	adapter->clean_rx(adapter, &work_done, budget);
>  
> -	/* If no Tx and not enough Rx work done, exit the polling mode */
> -	if ((!tx_cleaned && (work_done < budget))) {
> +	/* If budget not fully consumed, exit the polling mode */
> +	if (work_done < budget) {
>  		if (adapter->itr_setting & 3)
>  			e1000_set_itr(adapter);
>  		netif_rx_complete(poll_dev, napi);
> diff --git a/drivers/net/ixgb/ixgb_main.c b/drivers/net/ixgb/ixgb_main.c
> index a8bef52..d2fb88d 100644
> --- a/drivers/net/ixgb/ixgb_main.c
> +++ b/drivers/net/ixgb/ixgb_main.c
> @@ -1787,14 +1787,13 @@ ixgb_clean(struct napi_struct *napi, int budget)
>  {
>  	struct ixgb_adapter *adapter = container_of(napi, struct ixgb_adapter, napi);
>  	struct net_device *netdev = adapter->netdev;
> -	int tx_cleaned;
>  	int work_done = 0;
>  
> -	tx_cleaned = ixgb_clean_tx_irq(adapter);
> +	ixgb_clean_tx_irq(adapter);
>  	ixgb_clean_rx_irq(adapter, &work_done, budget);
>  
> -	/* if no Tx and not enough Rx work done, exit the polling mode */
> -	if((!tx_cleaned && (work_done == 0))) {
> +	/* If budget not fully consumed, exit the polling mode */
> +	if (work_done < budget) {
>  		netif_rx_complete(netdev, napi);
>  		ixgb_irq_enable(adapter);
>  	}
> diff --git a/drivers/net/ixgbe/ixgbe_main.c b/drivers/net/ixgbe/ixgbe_main.c
> index 7c31930..a564916 100644
> --- a/drivers/net/ixgbe/ixgbe_main.c
> +++ b/drivers/net/ixgbe/ixgbe_main.c
> @@ -1468,15 +1468,15 @@ static int ixgbe_clean(struct napi_struct *napi, int budget)
>  	struct ixgbe_adapter *adapter = container_of(napi,
>  					struct ixgbe_adapter, napi);
>  	struct net_device *netdev = adapter->netdev;
> -	int tx_cleaned = 0, work_done = 0;
> +	int work_done = 0;
>  
>  	/* In non-MSIX case, there is no multi-Tx/Rx queue */
> -	tx_cleaned = ixgbe_clean_tx_irq(adapter, adapter->tx_ring);
> +	ixgbe_clean_tx_irq(adapter, adapter->tx_ring);
>  	ixgbe_clean_rx_irq(adapter, &adapter->rx_ring[0], &work_done,
>  			   budget);
>  
> -	/* If no Tx and not enough Rx work done, exit the polling mode */
> -	if ((!tx_cleaned && (work_done < budget))) {
> +	/* If budget not fully consumed, exit the polling mode */
> +	if (work_done < budget) {
>  		netif_rx_complete(netdev, napi);
>  		ixgbe_irq_enable(adapter);
>  	}