1. 14 Jul, 2011 1 commit
    • Len Brown's avatar
      x86, intel, power: Initialize MSR_IA32_ENERGY_PERF_BIAS · abe48b10
      Len Brown authored
      Since 2.6.36 (23016bf0), Linux prints the existence of "epb" in /proc/cpuinfo,
      Since 2.6.38 (d5532ee7), the x86_energy_perf_policy(8) utility has
      been available in-tree to update MSR_IA32_ENERGY_PERF_BIAS.
      
      However, the typical BIOS fails to initialize the MSR, presumably
      because this is handled by high-volume shrink-wrap operating systems...
      
      Linux distros, on the other hand, do not yet invoke x86_energy_perf_policy(8).
      As a result, WSM-EP, SNB, and later hardware from Intel will run in its
      default hardware power-on state (performance), which assumes that users
      care for performance at all costs and not for energy efficiency.
      While that is fine for performance benchmarks, the hardware's intended default
      operating point is "normal" mode...
      
      Initialize the MSR to the "normal" by default during kernel boot.
      
      x86_energy_perf_policy(8) is available to change the default after boot,
      should the user have a different preference.
      Signed-off-by: default avatarLen Brown <len.brown@intel.com>
      Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1107140051020.18606@x980Acked-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
      Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
      Cc: <stable@kernel.org>
      abe48b10
  2. 11 Jul, 2011 15 commits
  3. 10 Jul, 2011 9 commits
  4. 09 Jul, 2011 15 commits