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 <[email protected]>
Tested-by: Alexey Kodanev <[email protected]>
Reviewed-by: Linda Knippers <[email protected]>
---
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);
--
1.8.3.1
On Tue, 9 Dec 2014 10:43:19 +0900
Ethan Zhao <[email protected]> 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 <[email protected]>
> Tested-by: Alexey Kodanev <[email protected]>
> Reviewed-by: Linda Knippers <[email protected]>
Acked-by: Kristen Carlson Accardi <[email protected]>
> ---
> 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);
On Wednesday, December 10, 2014 12:28:49 PM Kristen Carlson Accardi wrote:
> On Tue, 9 Dec 2014 10:43:19 +0900
> Ethan Zhao <[email protected]> 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 <[email protected]>
> > Tested-by: Alexey Kodanev <[email protected]>
> > Reviewed-by: Linda Knippers <[email protected]>
>
> Acked-by: Kristen Carlson Accardi <[email protected]>
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.