[ovs-dev] [Patch] Documentation for DPDK IVSHMEM VM Communications

[Polehn, Mike A]

The setup for packet transfer between the switch and VM by shared memory (IVSHMEM) is moderately complex and most details are not easily found.  Also this is a different transfer method than user side vhost which copies between the separate memory spaces at a cost of slower packet rate or higher CPU core load(s). Shared memory transfer is much more efficient transfer method since it is only copying packet pointers and not packet data. However lacks security since the VM can see all the packet buffer memory space at all times. However efficiency vs security is something only the user of the system can determine since they know if the system is a closed environment or not.

I put in enough details to allow someone, who has not been intimately involved in doing IVSHMEM packet processing work to setup and get the shared memory transfer working in a short time given today's current build state. Including the system packages to allow a proper build (qemu in particular) maybe over kill, but figuring out these required packages can be very time consuming. Unless it is working, you cannot experiment with or test the IVSHMEM shared memory operation or even move the method forward as an alternative setup, the correct information is just not readily available, weeks can easily be spent (only if you are very determined to get it to work).

The INSTALL.DPDK also needs to be update for DPDK 1.7 ...

Would you like to have this put in as separate doc, INSTALL.DPDK.IVSHMEM?

Mike

-----Original Message-----
From: Pravin Shelar [mailto:pshelar at nicira.com] 
Sent: Friday, August 29, 2014 3:54 PM
To: Polehn, Mike A
Cc: dev at openvswitch.com
Subject: Re: [ovs-dev] [Patch] Documentation for DPDK IVSHMEM VM Communications

On Fri, Aug 15, 2014 at 7:07 AM, Polehn, Mike A <mike.a.polehn at intel.com> wrote:
> Adds documentation on how to run IVSHMEM communication through VM.
>
I think INSTALL.DPDK is getting rather large and hard to understand with all details.
so I dropped "Alternative method to get QEMU, download and build from OVDK" section.
We can add this documentation to separate file once vhost support is added.

Thanks.