> Add two new power management intrinsics, and provide an implementation > in eal/x86 based on UMONITOR/UMWAIT instructions. The instructions > are implemented as raw byte opcodes because there is not yet widespread > compiler support for these instructions. > > The power management instructions provide an architecture-specific > function to either wait until a specified TSC timestamp is reached, or > optionally wait until either a TSC timestamp is reached or a memory > location is written to. The monitor function also provides an optional > comparison, to avoid sleeping when the expected write has already > happened, and no more writes are expected. > > For more details, Please reference Intel SDM Volume 2.
I really would like to see feedbacks from other arch maintainers. Unfortunately they were not Cc'ed. Also please mark the new functions as experimental.