On Wednesday, December 10, 2014 12:28:49 PM Kristen Carlson Accardi wrote:
> On Tue, 9 Dec 2014 10:43:19 +0900
> Ethan Zhao <ethan.zhao@xxxxxxxxxx> wrote:
>
> > To force loading on Oracle Sun X86 servers, provide one kernel command line
> > parameter
> >
> > intel_pstate = force
> >
> > For those who be aware of the risk of no power capping capabily working and
> > try to get better performance with this driver.
> >
> > Signed-off-by: Ethan Zhao <ethan.zhao@xxxxxxxxxx>
> > Tested-by: Alexey Kodanev <alexey.kodanev@xxxxxxxxxx>
> > Reviewed-by: Linda Knippers <linda.knippers@xxxxxx>
>
> Acked-by: Kristen Carlson Accardi <kristen@xxxxxxxxxxxxxxx>
Patch applied, but I had to rebase it on top of the HWP changes from Dirk.
Please check my linux-next branch for the result and let me know if there's
anything wrong with it.
> > ---
> > v2: change to hardware vendor specific naming parameter.
> > v4: refine code and doc.
> > v5&v6: fix a typo in doc.
> > v7: change enum PCC to PPC.
> > v8: change the name of kernel command line parameter to generic one.
> > v9: refine doc
> >
> > Documentation/kernel-parameters.txt | 5 +++++
> > drivers/cpufreq/intel_pstate.c | 6 +++++-
> > 2 files changed, 10 insertions(+), 1 deletion(-)
> >
> > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> > index 479f332..7d0983e 100644
> > --- a/Documentation/kernel-parameters.txt
> > +++ b/Documentation/kernel-parameters.txt
> > @@ -1446,6 +1446,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
> > disable
> > Do not enable intel_pstate as the default
> > scaling driver for the supported processors
> > + force
> > + Enable intel_pstate on systems that prohibit it by default
> > + in favor of acpi-cpufreq. Forcing the intel_pstate driver
> > + instead of acpi-cpufreq may disable platform features, such
> > + as thermal controls and power capping, that rely on ACPI
> > + P-States information being indicated to OSPM and therefore
> > + should be used with caution. This option does not work with
> > + processors that aren't supported by the intel_pstate driver
> > + or on platforms that use pcc-cpufreq instead of acpi-cpufreq.
> >
> > intremap= [X86-64, Intel-IOMMU]
> > on enable Interrupt Remapping (default)
> > diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
> > index 1bb62ca..2654e13 100644
> > --- a/drivers/cpufreq/intel_pstate.c
> > +++ b/drivers/cpufreq/intel_pstate.c
> > @@ -866,6 +866,7 @@ static struct cpufreq_driver intel_pstate_driver = {
> > };
> >
> > static int __initdata no_load;
> > +static unsigned int force_load;
> >
> > static int intel_pstate_msrs_not_valid(void)
> > {
> > @@ -1003,7 +1004,8 @@ static bool intel_pstate_platform_pwr_mgmt_exists(void)
> > case PSS:
> > return intel_pstate_no_acpi_pss();
> > case PPC:
> > - return intel_pstate_has_acpi_ppc();
> > + return intel_pstate_has_acpi_ppc() &&
> > + (!force_load);
> > }
> > }
> >
> > @@ -1078,6 +1080,8 @@ static int __init intel_pstate_setup(char *str)
> >
> > if (!strcmp(str, "disable"))
> > no_load = 1;
> > + if (!strcmp(str, "force"))
> > + force_load = 1;
> > return 0;
> > }
> > early_param("intel_pstate", intel_pstate_setup);
>
> --
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--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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