Big.little instrumentation

Meta:
Headline:
Acceptance:
Roadmap id: KWG2012-BIG-LITTLE-MIGRATION

[david-rusling] Trace events should be
       {start migration, end migration} for each CPU pair
       Appropriate cpu-freq, cpu-idle events that initiate migration
       Debug / Test events that initiate migration

[david-rusling] Statistics - I'd like to be able to graph battery life / current drawn against migration events over time

[jakub-pavelek 2012-11-09] Is this blueprint still alive? No updates for half a year, I would like to get rid of Essentiel blueprint that is stale and showing in my team's backlog. Consider this an eviction notice :)

[davem] 2012-11-28] I think this blueprint should be considered stale/obsolete. Active b.L switcher work is being tracked in a separate planning spreadsheet, which overrides what is here. Performance measurement related work has been preempted by more recent benchmarking activities.

Work items:
[dave-martin-arm] Investigate tracepoint suitability for extracting big.LITTLE statistics: DONE
[dave-martin-arm] Itemize required instrumentation metrics: DONE
[vishalbhoj] Enable cpufreq stats: DONE
[dave-martin-arm] Add trace events for switching latency measurement: DONE
[dave-martin-arm] Enable instrumentation for test builds: DONE
Specify tests to track switch times across builds: TODO
Implement tests to track switch times across builds: TODO
Specify tests to track switching when running combinations of governors and payloads: TODO
Implement tests to track switching when running combinations of governors and payloads: TODO