RE: [PATCH net-next,v4] hyperv: Add support for virtual Receive Side Scaling (vRSS)

[Haiyang Zhang]

> -----Original Message-----
> From: Sharat Masetty [mailto:sharat04@xxxxxxxxx]
> Sent: Monday, April 7, 2014 6:13 PM
> To: David Miller
> Cc: Haiyang Zhang; Linux Netdev List; KY Srinivasan; olaf@xxxxxxxxx;
> jasowang@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; driverdev-
> devel@xxxxxxxxxxxxxxxxxxxxxx
> Subject: Re: [PATCH net-next,v4] hyperv: Add support for virtual Receive Side
> Scaling (vRSS)
> 
> Hi Zhang,
> 
> How is this beneficial when compared to RPS(receive packet steering)?
> Can you please provide more details on what this patch does?

This patch supports the virtual RSS feature provided by Hyper-V hosts. Currently,
the interrupts are received on only one CPU per vNIC. With this feature, we can 
receive interrupts from multiple CPUs and VMBus channels for one vNIC. Outgoing 
packets are put into multiple channels as well. So the network throughput can 
scale up with the number of CPUs for a VM.

RPS is basically a software implementation of RSS. This is an online doc about 
these features:
https://www.kernel.org/doc/Documentation/networking/scaling.txt

Thanks,
- Haiyang