Re: [Intel-wired-lan] [PATCH net v2] e1000e: Disable TSO on i219-LM card to increase speed

[Tony Nguyen <anthony.l.nguyen@intel.com>]

On 12/21/2022 5:25 AM, Mateusz Palczewski wrote:
> While using i219-LM card currently it was only possible to achieve
> about 60% of maximum speed due to regression introduced in Linux 5.8-rc1.
> This was caused by TSO not being disabled by default despite commit
> f29801030ac6 implementation. Fix that by moving the part of the code
> responsible for this outside of adapter->flags & FLAG_TSO_FORCE check.

Have you looked into changing the initial netdev features to prevent 
this? Seems like it would be more effective to have it off fixed for 
this MAC over turning it off in the watchdog every time.

> 
> Fixes: f29801030ac6 ("e1000e: Disable TSO for buffer overrun workaround")
> Signed-off-by: Mateusz Palczewski <mateusz.palczewski@intel.com>
> ---
>   v2: Fixed commit message and comment inside the code
> ---
>   drivers/net/ethernet/intel/e1000e/netdev.c | 12 ++++++++----
>   1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
> index 04acd1a992fa..2f5cf125ff77 100644
> --- a/drivers/net/ethernet/intel/e1000e/netdev.c
> +++ b/drivers/net/ethernet/intel/e1000e/netdev.c
> @@ -5307,10 +5307,6 @@ static void e1000_watchdog_task(struct work_struct *work)
>   					/* oops */
>   					break;
>   				}
> -				if (hw->mac.type == e1000_pch_spt) {
> -					netdev->features &= ~NETIF_F_TSO;
> -					netdev->features &= ~NETIF_F_TSO6;
> -				}
>   			}
>   
>   			/* enable transmits in the hardware, need to do this
> @@ -5326,6 +5322,14 @@ static void e1000_watchdog_task(struct work_struct *work)
>   			if (phy->ops.cfg_on_link_up)
>   				phy->ops.cfg_on_link_up(hw);
>   
> +			/* Disable TSO for i219 to avoid transfer speed
> +			 * being capped at 60%.
> +			 */
> +			if (hw->mac.type == e1000_pch_spt) {
> +					netdev->features &= ~NETIF_F_TSO;
> +					netdev->features &= ~NETIF_F_TSO6;
> +			}
> +
>   			netif_wake_queue(netdev);
>   			netif_carrier_on(netdev);
>   
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