[dpdk-dev] [PATCH v4 0/11] add json power policy interface for containers

[David Hunt <david.hunt@intel.com>]

The current vm_power_manager example app has the capability to accept power
policies from virtual machines via virtio-serial channels. These power
policies  allow a virtual machine to give information to the power manager
to allow the power manager take care of the power management of the virtual
machine based on the information in the policy.

This power policy functionality is limited to virtual machines sending
the policies to the power manager (which runs in the Host OS), and a solution
was needed for additional methods of sending power policies to the power
manager app.

The main use-case for this modification is for containers and host
applications that wish to send polices to the power manager.

This patchset adds the capability to send power polices and power commands
to the vm_power_manager app via JSON strings through a fifo on the file
system.
For example, given the following file, policy.json:

{"policy": {
  "name": "ubuntu2",
  "command": "create",
  "policy_type": "TIME",
  "busy_hours":[ 17, 18, 19, 20, 21, 22, 23 ],
  "quiet_hours":[ 2, 3, 4, 5, 6 ],
  "core_list":[ 11, 12, 13 ]
}}

Then running the command:

cat policy.json >/tmp/powermonitor/fifo

The policy is sent to the vm_power_manager. The power manager app then parses
the JSON data, and inserts the policy into the array of policies.

Part of the patch series contains documentation updates to give all the
details of the valid name-value pairs, the data types, etc.

Patch v2:
  * Fixed review comments from Stephen Hemminger and Lei A Yao.
  * Added a check in the Makefile for libjansson-dev. Will Warn user and build
    without JSON functionality if not present, will build including JSON
    functionality if it is present.

Patch v3:
  * Added meson/ninja support for vm_power_manager and guest_cli apps
  * Fixed compilation issue with guest_cli app

Patch v4:
  * Split out some unrelated changes to separate patches in the set
  * Some changes out of review by Anatoly (Thanks!)

[01/11] examples/power: add checks around hypervisor
[02/11] examples/power: allow for number of vms to be zero
[03/11] lib/power: add changes for host commands/policies
[04/11] examples/power: add necessary changes to guest app
[05/11] examples/power: add host channel to power manager
[06/11] examples/power: increase allowed number of clients
[07/11] examples/power: add json string handling
[08/11] examples/power: clean up verbose messages
[09/11] examples/power: add meson/ninja build support
[10/11] doc/vm_power_manager: add JSON interface API info
[11/11] examples/power: add json example files