On 2/1/23 01:55, Thomas Monjalon wrote:
31/01/2023 19:14, Jerin Jacob:
On Wed, Jan 18, 2023 at 9:15 PM Rongwei Liu <rongw...@nvidia.com> wrote:
When a DPDK application must be upgraded,
the traffic downtime should be shortened as much as possible.
During the migration time, the old application may stay alive
while the new application is starting and being configured.
In order to optimize the switch to the new application,
the old application may need to be aware of the presence
of the new application being prepared.
This is achieved with a new API allowing the user to change the
new application state to standby and active later.
The added function is trying to apply the new state to all probed
ethdev ports. To make this API simple and easy to use,
the same flags have to be accepted by all devices.
This is the scenario of operations in the old and new applications:
. device: already configured by the old application
. new: start as active
. new: probe the same device
How to probe same device if is already bind to another application?
vfio-pci wont allow this.
I missed that part.
There is no way to share a VFIO device between 2 applications?
As I understand multi-process shares an VFIO device between
many application. As far as I remember it is just required to
pass corresponding file descriptor to another application.
Anyway I fully agree that the patch requires more documentation
in doc/guides/ with the description of live migration theory of
operations.
. new: set as standby
. new: configure the device
. device: has configurations from old and new applications
. old: clear its device configuration
. device: has only 1 configuration from new application
. new: set as active
. device: downtime for connecting all to the new application
. old: shutdown
