(adding eas-dev)
On 10/09/2015 01:41 AM, Patrick Bellasi wrote:
The users might not be happy though
so we could favor performance for RT tasks to avoid breaking legacy software and ask users that care about energy to migrate to deadline where we actually know the performance constraints of the tasks.
Given that at the moment RT tasks are treated no differently than CFS tasks w.r.t. cpu frequency I'd expect that we could get away without any sort of perf bias for RT bandwidth, which I think would be cost prohibitive for power.
Are you specifically considering instantaneous power? Because from a power standpoint I cannot see any difference for example w.r.t having a batch CFS task.
From an energy standpoint instead, do not you think that a "race-to-idle" policy could be better at least for RT-BATCH tasks?
Sorry I should have said energy rather than power...
From my experience race to idle has never panned out as an
energy-efficient strategy, presumably due to the nonlinear increase in power cost as performance increases. Because of this I think a policy of increasing the OPP when RT tasks are runnable will cause a net increase in energy consumption, which need not be incurred since RT tasks do not receive this preferential OPP treatment today.