Re: [PATCH net] e1000e: Change wthresh to 1 to avoid possible Tx stalls.

[Jeff Kirsher <jeffrey.t.kirsher@intel.com>]

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On Wed, 2012-06-06 at 01:43 -0700, Hiroaki SHIMODA wrote:
> Denys Fedoryshchenko reported Tx stalls on e1000e with BQL enabled.
> 
> e1000e has WTHRESH which determines when Tx descripters are written
> back and successive Tx interrupts are generated, and setting WTHRESH
> to 5 gives efficient bus utilization but this cause possible Tx
> stalls,
> especially on BQL enabled system.
> 
> To avoid possible Tx stalls, change WTHRESH to 1.
> 
> Reported-by: Denys Fedoryshchenko <denys@visp.net.lb>
> Tested-by: Denys Fedoryshchenko <denys@visp.net.lb>
> Signed-off-by: Hiroaki SHIMODA <shimoda.hiroaki@gmail.com>
> ---
>  drivers/net/ethernet/intel/e1000e/e1000.h  |    6 +++---
>  drivers/net/ethernet/intel/e1000e/netdev.c |    2 +-
>  2 files changed, 4 insertions(+), 4 deletions(-) 

After further internal review, NACK.

This patch will cause unacceptable performance issues with non-ESB2
parts.

I am dropping this patch from my queue.


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