I think part of the problem is that from where I stand, there's no way to tell my programming language (java) "Hey, this thing doesn't need horsepower so prefer to schedule it on little cores." Or conversely "Hey, this thing is CPU sensitive, don't put it on a LITTLE core."
I don't think (but could be wrong) that C++ has a platform independent way of doing this either. I'm not even sure if such an API is exposed from the Windows or linux kernel (though I'd imagine it is).
That to me is the bigger issue here. I can specify which core a thread should run on, but I can't specify what type of core it should run on.
Windows has an API for that, I don't think it's widely used though:
> On platforms with heterogeneous processors, the QoS of a thread may restrict scheduling to a subset of processors, or indicate a preference for a particular class of processor.
POSIX threads, used by C/C++ and a lot of other language runtimes is somewhat platform independent and provides for affinity, priority and policy controls.
None of the standard attributes (AFAIK) are directly "put me on a tiny core", but they frequently work hand in hand with those decisions. Lower your priority and the scheduler dumps you on some low clocked small core kinds of effects when its not busy. Or if you have machine knowledge just set your core affinity with pthread_setaffinity_np() which as the extension states is non-portable but can directly translate to "run me on a tiny core" if the right mask is provided.
At least in C/C++ most if not all modern platforms provide these kinds of controls and metadata and while the API might change a bit writing a couple versions of schedule_me_on_a_tiny_core() for each target platform is fairly trivial.
I don't think (but could be wrong) that C++ has a platform independent way of doing this either. I'm not even sure if such an API is exposed from the Windows or linux kernel (though I'd imagine it is).
That to me is the bigger issue here. I can specify which core a thread should run on, but I can't specify what type of core it should run on.