RE: [PATCH] e1000e: Disable TSO for buffer overrun workaround

[Brown, Aaron F]

> From: netdev-owner@xxxxxxxxxxxxxxx <netdev-owner@xxxxxxxxxxxxxxx> On
> Behalf Of Kai-Heng Feng
> Sent: Thursday, May 7, 2020 7:21 AM
> To: Kirsher, Jeffrey T <jeffrey.t.kirsher@xxxxxxxxx>
> Cc: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>; David S. Miller
> <davem@xxxxxxxxxxxxx>; Neftin, Sasha <sasha.neftin@xxxxxxxxx>; Dima
> Ruinskiy <dima.ruinskiy@xxxxxxxxx>; Avargil, Raanan
> <raanan.avargil@xxxxxxxxx>; moderated list:INTEL ETHERNET DRIVERS <intel-
> wired-lan@xxxxxxxxxxxxxxxx>; open list:NETWORKING DRIVERS
> <netdev@xxxxxxxxxxxxxxx>; open list <linux-kernel@xxxxxxxxxxxxxxx>
> Subject: [PATCH] e1000e: Disable TSO for buffer overrun workaround
> 
> Commit b10effb92e27 ("e1000e: fix buffer overrun while the I219 is
> processing DMA transactions") imposes roughly 30% performance penalty.
> 
> The commit log states that "Disabling TSO eliminates performance loss
> for TCP traffic without a noticeable impact on CPU performance", so
> let's disable TSO by default to regain the loss.
> 
> Fixes: b10effb92e27 ("e1000e: fix buffer overrun while the I219 is processing
> DMA transactions")
> BugLink: https://bugs.launchpad.net/bugs/1802691
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
> ---
>  drivers/net/ethernet/intel/e1000e/netdev.c | 4 ++++
>  1 file changed, 4 insertions(+)
Tested-by: Aaron Brown <aaron.f.brown@xxxxxxxxx>