Subject: Re: [REGRESSION] 2.6.24-rc7: e1000: Detected Tx Unit Hang

From: Badalian Vyacheslav <[email-masked]>
Date: Wed, 16 Jan 2008 12:02:28 +0300

applied to 2.6.24-rc7-git2
Have messages
Also have regression after apply patch.
System may do above 800mbs traffic before patch. After its "exit polling 
mode?" (4 CPU, 1 cpu get 100% si (process ksoftirqd/0), 3 CPU is IDLE)
After patch system was go to "exit polling mode" at above 600mbs.

Thanks.

> From: Frans Pop <[email-masked]>
> Date: Tue, 15 Jan 2008 06:25:10 +0100
>
>   
>> kernel: e1000: eth0: e1000_clean_tx_irq: Detected Tx Unit Hang
>>     
>
> Does this make the problem go away?
>
> (Note this isn't the final correct patch we should apply.  There
>  is no reason why this revert back to the older ->poll() logic
>  here should have any effect on the TX hang triggering...)
>
> diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c
> index 13d57b0..cada32c 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 work_done = 0;
> +	int tx_work = 0, work_done = 0;
>  
>  	/* Must NOT use netdev_priv macro here. */
>  	adapter = poll_dev->priv;
> @@ -3929,8 +3929,8 @@ 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)) {
> -		e1000_clean_tx_irq(adapter,
> -				   &adapter->tx_ring[0]);
> +		tx_work = e1000_clean_tx_irq(adapter,
> +					     &adapter->tx_ring[0]);
>  		spin_unlock(&adapter->tx_queue_lock);
>  	}
>  
> @@ -3938,7 +3938,7 @@ e1000_clean(struct napi_struct *napi, int budget)
>  	                  &work_done, budget);
>  
>  	/* If budget not fully consumed, exit the polling mode */
> -	if (work_done < budget) {
> +	if (!tx_work && (work_done < budget)) {
>  		if (likely(adapter->itr_setting & 3))
>  			e1000_set_itr(adapter);
>  		netif_rx_complete(poll_dev, napi);
> --
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