[ovs-dev] [PATCH v2 0/6] Add OVS DPDK keep-alive functionality

[Ben Pfaff]

On Thu, Apr 27, 2017 at 05:18:04PM -0400, Aaron Conole wrote:
> Bhanuprakash Bodireddy <bhanuprakash.bodireddy at intel.com> writes:
> 
> > This patch is aimed at achieving Fastpath Service Assurance in
> > OVS-DPDK deployments. This commit adds support for monitoring the packet
> > processing cores(pmd thread cores) by dispatching heartbeats at regular
> > intervals. Incase of heartbeat miss the failure shall be detected &
> > reported to higher level fault management systems/frameworks.
> >
> > The implementation uses POSIX shared memory object for storing the
> > events that will be read by monitoring framework. keep-alive feature
> > can be enabled through below OVSDB settings.
> 
> I've been thinking about this design, and I'm concerned - shared memory
> is inflexible, and allows multiple actors to mess with the information.
> Is there a reason to use shared memory?  I am not sure of what
> advantage this form of reporting has vs. simply using a message
> passing interface.  With messages there is clear abstraction, and the
> projects / processes are truly separated.  Shared memory is leads to a
> situation of inextricably coupling two (or more) processes.

Shared memory is great within a process, but it has drawbacks as an
inter-process interface.  Bhanu, is there a reason that we need the same
interface intra- and inter-process?  For example, OVS could have a
dedicated thread that monitors the shared memory interface and, on
failure, reports the problem over a Unix domain socket.