Re: [Xen-devel] [PATCH v2 0/9] Porting the intel_pstate driver to Xen

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

Hi Jan,

> On 28/04/2015 16:37, Wei Wang wrote
> > Changes:
> > *NO.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.
> >
> > *NO.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
> >
> > *NO.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.
> >
> > *NO.4 Moved the declarations under xen/include/acpi to an x86-specific
> > header.
> >
> > ** Basic Description **
> > 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 (9):
> >   x86/acpi: add a common interface for x86 cpu matching
> >   x86/intel_pstate: add some calculation related support
> >   x86/cpu_hotplug: add the unregister_cpu_notifier function to support
> >     CPU hotplug
> >   x86/intel_pstate: add new policy fields and a new driver interface
> >   x86/intel_pstate: relocate the driver register/unregister function
> >   x86/intel_pstate: the main boby of the intel_pstate driver
> >   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
> >   x86/intel_pstate: enable xenpm to control the intel_pstate driver
> >
> >  tools/libxc/include/xenctrl.h            |  14 +-
> >  tools/libxc/xc_pm.c                      |  17 +-
> >  tools/misc/xenpm.c                       | 104 +++-
> >  xen/arch/x86/acpi/cpufreq/Makefile       |   1 +
> >  xen/arch/x86/acpi/cpufreq/cpufreq.c      |   9 +-
> >  xen/arch/x86/acpi/cpufreq/intel_pstate.c | 869
> > +++++++++++++++++++++++++++++++
> >  xen/arch/x86/cpu/common.c                |  39 ++
> >  xen/arch/x86/cpu/mwait-idle.c            |  30 +-
> >  xen/common/cpu.c                         |   7 +
> >  xen/drivers/acpi/pmstat.c                | 106 +++-
> >  xen/drivers/cpufreq/cpufreq.c            |  27 +-
> >  xen/drivers/cpufreq/utility.c            |   5 +
> >  xen/include/acpi/cpufreq/cpufreq.h       |  45 +-
> >  xen/include/asm-x86/acpi.h               |   4 +
> >  xen/include/asm-x86/cpufeature.h         |   1 +
> >  xen/include/asm-x86/div64.h              |  68 +++
> >  xen/include/asm-x86/msr-index.h          |   3 +
> >  xen/include/asm-x86/processor.h          |  10 +
> >  xen/include/public/sysctl.h              |  16 +-
> >  xen/include/xen/cpu.h                    |   1 +
> >  xen/include/xen/kernel.h                 |  30 ++
> >  21 files changed, 1300 insertions(+), 106 deletions(-)  create mode
> > 100644 xen/arch/x86/acpi/cpufreq/intel_pstate.c
> >
> > --
> > 1.9.1

Do you have any comments on this version?

Best,
Wei


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