[dpdk-dev] [DPDK] net/e1000: fix buffer overrun while i219 processing DMA transactions

[Zhang, Qi Z]

> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Xiao Zhang
> Sent: Monday, July 8, 2019 9:37 PM
> To: dev at dpdk.org
> Cc: Lu, Wenzhuo <wenzhuo.lu at intel.com>; Zhao1, Wei
> <wei.zhao1 at intel.com>; Zhang, Xiao <xiao.zhang at intel.com>
> Subject: [dpdk-dev] [DPDK] net/e1000: fix buffer overrun while i219
> processing DMA transactions
> 
> Intel® 100/200 Series Chipset platforms reduced the round-trip latency for the
> LAN Controller DMA accesses, causing in some high performance cases a buffer
> overrun while the I219 LAN Connected Device is processing the DMA
> transactions. I219LM and I219V devices can fall into unrecovered Tx hang
> under very stressfully UDP traffic and multiple reconnection of Ethernet cable.
> This Tx hang of the LAN Controller is only recovered if the system is rebooted.
> Slightly slow down DMA access by reducing the number of outstanding
> requests.
> This workaround could have an impact on TCP traffic performance on the
> platform. Disabling TSO eliminates performance loss for TCP traffic without a
> noticeable impact on CPU performance.
> 
> Please, refer to I218/I219 specification update:
> https://www.intel.com/content/www/us/en/embedded/products/networking
> /
> ethernet-connection-i218-family-documentation.html
> 
> Signed-off-by: Xiao Zhang <xiao.zhang at intel.com>

Acked-by: Qi Zhang <qi.z.zhang at intel.com>

Applied to dpdk-next-net-intel.

Thanks
Qi