[PATCHv3 0/4] Update cpupower and make it more accurate

["Natarajan, Janakarajan" <Janakarajan.Natarajan@amd.com>]

This patchset updates cpupower to make it more accurate by removing
the userspace to kernel transition and read_msr initiated IPI delays.

The first patch does a little re-arrangement of variables in the
cpuidle_monitor struct to prepare for a new flag.

The second patch introduces a per_cpu_schedule flag which, when set,
will allow cpupower to move to each of the cpus in the system. The
advantage of this is that the IPI latency is removed when reading the
APERF/MPERF registers, since an IPI is not generate for rdmsrs when
the source and destination cpus are the same for the IPI.

The third patch introduces the RDPRU instruction, which will allow
cpupower to not use the msr module for APERF/MPERF register reads.
This will remove the userspace to kernel transition delays when
reading the APERF/MPERF registers.

The fourth patch updates the ToDo file with ideas for further improving
the code handling the per_cpu_schedule flag.

v1->v2:
* Added cover letter.
* Used bind_cpu instead of rewriting the same code.
* Move needs_root to flag sub-struct.
* Introduce per_cpu_schedule flag.

v2->v3:
* Added ToDo patch to this set.
* Fix checkpatch warnings.

Janakarajan Natarajan (4):
  cpupower: Move needs_root variable into a sub-struct
  cpupower: mperf_monitor: Introduce per_cpu_schedule flag
  cpupower: mperf_monitor: Update cpupower to use the RDPRU instruction
  cpupower: ToDo: Update ToDo with ideas for per_cpu_schedule handling

 tools/power/cpupower/ToDo                     | 14 ++++
 tools/power/cpupower/utils/helpers/cpuid.c    |  4 ++
 tools/power/cpupower/utils/helpers/helpers.h  |  1 +
 .../utils/idle_monitor/amd_fam14h_idle.c      |  2 +-
 .../utils/idle_monitor/cpuidle_sysfs.c        |  2 +-
 .../utils/idle_monitor/cpupower-monitor.c     |  2 +-
 .../utils/idle_monitor/cpupower-monitor.h     |  5 +-
 .../utils/idle_monitor/hsw_ext_idle.c         |  2 +-
 .../utils/idle_monitor/mperf_monitor.c        | 64 +++++++++++++++----
 .../cpupower/utils/idle_monitor/nhm_idle.c    |  2 +-
 .../cpupower/utils/idle_monitor/snb_idle.c    |  2 +-
 11 files changed, 82 insertions(+), 18 deletions(-)

-- 
2.17.1