[Xen-devel] [PATCH v4 00/11] Porting the intel_pstate driver to Xen

[Wei Wang <wei.w.wang@xxxxxxxxx>]

V4 changes:
1) introduce a new struct, internal_governor, to "cpufreq_policy";
2) add a new header file, xen/include/asm-x86/cpufreq.h;
3) remove the APERF/MPERF feature detection code in cpufreq.c and powernow.c;
4) coding style changes.

Please check each patch's commit message for details.

V3 Changes:
1) coding style changes based on Jan's comments;
2) remove the function - unregister_cpu_notifier();
3) solve a bug in the CPU offline code (Patch 0007);
4) move the perf_limits struct into the per-CPU policy struct, so that
each CPU can be managed individually;
5) "load_intel_pstate" is changed local to the intel_pstate.c file, and
add its description to the xen-command-line.markdown.

V2 Changes:
1) The intel_pstate driver can be controlled via two ways:
A. min_perf_pct and max_perf_pct
   The user directly adjusts min_perf_pct and max_perf_pct to get what 
   they want. For example, if min_perf_pct=max_perf_pct=60%, then the 
   user is asking for something similar to a userspace governor with 
   setting the requested performance=60%.
B. set-scaling-governor
   This one is functionally redundant, since A. can achieve all the
   governor functions. It is remained to give people time to get
   familiar with method A.
   Users can choose from the four governors: Powersave, Ondemand,
   Powersave, Performance. The driver achieves the functionality of 
   the selected governor via adjusting the min_perf_pct and max_perf_pct
   itself.
2) The xenpm "get-cpufreq-para" displays the following things:
cpu id               : 10
affected_cpus        : 10
cpuinfo frequency    : max [3700000] min [1200000] cur [1400000]
scaling_driver       : intel_pstate
scaling_avail_gov    : performance powersave userspace ondemand
current_governor     : ondemand
max_perf_pct         : 100
min_perf_pct         : 32
turbo_pct            : 54
turbo mode           : enabled
3) Changed "intel_pstate=disable" to "intel_pstate=enable". 
If "intel_pstate=enable" is added, but the CPU does not support the
intel_pstate driver, the old P-state driver (acpi-cpufreq) will be loaded.
4) Moved the declarations under xen/include/acpi to an x86-specific header.

V1:
This patch series ports the intel_pstate driver from the Linux kernel to
Xen. The intel_pstate driver is used to tune P states for SandyBridge+
processors. It needs to be enabled by adding "intel_pstate=enable" to the
booting parameter list.

The intel_pstate.c file under xen/arch/x86/acpi/cpufreq/
contains all the logic for selecting the current P-state. It follows its
implementation in the kernel. In order to better support future Intel CPUs
(e.g. the HWP feature on Skylake+), intel_pstate changes to tune P-state
based on percentage values.

The xenpm tool is also upgraded to support the intel_pstate driver. If
intel_pstate is used, "get-cpufreq-para" displays percentage value based
feedback. If the intel_pstate driver is not enabled, xenpm will work in
the old style.

Wei Wang (11):
  x86/acpi: add a common interface for x86 cpu matching
  x86/intel_pstate: add some calculation related support
  x86/intel_pstate: add new policy fields and a new driver interface
  x86/intel_pstate: avoid calling cpufreq_add_cpu() twice
  x86/intel_pstate: relocate the driver register function
  x86/intel_pstate: APERF/MPERF feature detect
  x86/intel_pstate: the main boby of the intel_pstate driver
  x86/intel_pstate: changes in cpufreq_del_cpu for CPU offline
  x86/intel_pstate: add a booting param to select the driver to load
  x86/intel_pstate: support the use of intel_pstate in pmstat.c
  tools: enable xenpm to control the intel_pstate driver

 docs/misc/xen-command-line.markdown      |   7 +
 tools/libxc/include/xenctrl.h            |  14 +-
 tools/libxc/xc_pm.c                      |  17 +-
 tools/misc/xenpm.c                       | 116 +++-
 xen/arch/x86/acpi/cpufreq/Makefile       |   1 +
 xen/arch/x86/acpi/cpufreq/cpufreq.c      |  15 +-
 xen/arch/x86/acpi/cpufreq/intel_pstate.c | 876 +++++++++++++++++++++++++++++++
 xen/arch/x86/acpi/cpufreq/powernow.c     |   6 +-
 xen/arch/x86/cpu/common.c                |  41 ++
 xen/arch/x86/cpu/mwait-idle.c            |  28 +-
 xen/drivers/acpi/pmstat.c                | 148 +++++-
 xen/drivers/cpufreq/cpufreq.c            |  22 +-
 xen/drivers/cpufreq/utility.c            |   3 +
 xen/include/acpi/cpufreq/cpufreq.h       |  54 +-
 xen/include/asm-x86/cpufeature.h         |   1 +
 xen/include/asm-x86/cpufreq.h            |  34 ++
 xen/include/asm-x86/div64.h              |  78 +++
 xen/include/asm-x86/msr-index.h          |   3 +
 xen/include/asm-x86/processor.h          |  10 +
 xen/include/public/sysctl.h              |  16 +-
 xen/include/xen/kernel.h                 |  12 +
 21 files changed, 1380 insertions(+), 122 deletions(-)
 create mode 100644 xen/arch/x86/acpi/cpufreq/intel_pstate.c
 create mode 100644 xen/include/asm-x86/cpufreq.h

-- 
1.9.1


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