| Message ID | 20250213160741.445351-1-darcari@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v4] intel_idle: introduce 'no_native' module parameter | expand |
On Thu, Feb 13, 2025 at 5:07 PM David Arcari <darcari@redhat.com> wrote: > > Since commit 18734958e9bf ("intel_idle: Use ACPI _CST for processor models > without C-state tables") the intel_idle driver has had the ability to use > the ACPI _CST to populate C-states when the processor model is not > recognized. However, even when the processor model is recognized (native > mode) there are cases where it is useful to make the driver ignore the per > cpu idle states in lieu of ACPI C-states (such as specific application > performance). Add the 'no_native' module parameter to provide this > functionality. > > Cc: Jonathan Corbet <corbet@lwn.net> > Cc: Jacob Pan <jacob.jun.pan@linux.intel.com> > Cc: Len Brown <lenb@kernel.org> > Cc: David Arcari <darcari@redhat.com> > Cc: Artem Bityutskiy <dedekind1@gmail.com> > Cc: Prarit Bhargava <prarit@redhat.com> > Cc: linux-doc@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: David Arcari <darcari@redhat.com> > --- > v4: fix !CONFIG_ACPI_PROCESSOR_CSTATE compilation issue Artem, have all of your comments been addressed in this version? > v3: more documentation cleanup > v2: renamed parameter, cleaned up documentation > > Documentation/admin-guide/pm/intel_idle.rst | 18 +++++++++++++----- > drivers/idle/intel_idle.c | 16 ++++++++++++++++ > 2 files changed, 29 insertions(+), 5 deletions(-) > > diff --git a/Documentation/admin-guide/pm/intel_idle.rst b/Documentation/admin-guide/pm/intel_idle.rst > index 39bd6ecce7de..5940528146eb 100644 > --- a/Documentation/admin-guide/pm/intel_idle.rst > +++ b/Documentation/admin-guide/pm/intel_idle.rst > @@ -192,11 +192,19 @@ even if they have been enumerated (see :ref:`cpu-pm-qos` in > Documentation/admin-guide/pm/cpuidle.rst). > Setting ``max_cstate`` to 0 causes the ``intel_idle`` initialization to fail. > > -The ``no_acpi`` and ``use_acpi`` module parameters (recognized by ``intel_idle`` > -if the kernel has been configured with ACPI support) can be set to make the > -driver ignore the system's ACPI tables entirely or use them for all of the > -recognized processor models, respectively (they both are unset by default and > -``use_acpi`` has no effect if ``no_acpi`` is set). > +The ``no_acpi``, ``use_acpi`` and ``no_native`` module parameters are > +recognized by ``intel_idle`` if the kernel has been configured with ACPI > +support. In the case that ACPI is not configured these flags have no impact > +on functionality. > + > +``no_acpi`` - Do not use ACPI at all. Only native mode is available, no > +ACPI mode. > + > +``use_acpi`` - No-op in ACPI mode, the driver will consult ACPI tables for > +C-states on/off status in native mode. > + > +``no_native`` - Work only in ACPI mode, no native mode available (ignore > +all custom tables). > > The value of the ``states_off`` module parameter (0 by default) represents a > list of idle states to be disabled by default in the form of a bitmask. > diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c > index 118fe1d37c22..b0be5ef43ffc 100644 > --- a/drivers/idle/intel_idle.c > +++ b/drivers/idle/intel_idle.c > @@ -1695,6 +1695,10 @@ static bool force_use_acpi __read_mostly; /* No effect if no_acpi is set. */ > module_param_named(use_acpi, force_use_acpi, bool, 0444); > MODULE_PARM_DESC(use_acpi, "Use ACPI _CST for building the idle states list"); > > +static bool no_native __read_mostly; /* No effect if no_acpi is set. */ > +module_param_named(no_native, no_native, bool, 0444); > +MODULE_PARM_DESC(no_native, "Ignore cpu specific (native) idle states in lieu of ACPI idle states"); > + > static struct acpi_processor_power acpi_state_table __initdata; > > /** > @@ -1834,6 +1838,11 @@ static bool __init intel_idle_off_by_default(unsigned int flags, u32 mwait_hint) > } > return true; > } > + > +static inline bool ignore_native(void) > +{ > + return no_native & !no_acpi; > +} > #else /* !CONFIG_ACPI_PROCESSOR_CSTATE */ > #define force_use_acpi (false) > > @@ -1843,6 +1852,7 @@ static inline bool intel_idle_off_by_default(unsigned int flags, u32 mwait_hint) > { > return false; > } > +static inline bool ignore_native(void) { return false; } > #endif /* !CONFIG_ACPI_PROCESSOR_CSTATE */ > > /** > @@ -2328,6 +2338,12 @@ static int __init intel_idle_init(void) > pr_debug("MWAIT substates: 0x%x\n", mwait_substates); > > icpu = (const struct idle_cpu *)id->driver_data; > + if (ignore_native()) { > + if (icpu) { > + pr_debug("ignoring native cpu idle states\n"); > + icpu = NULL; > + } > + } > if (icpu) { > if (icpu->state_table) > cpuidle_state_table = icpu->state_table; > -- > 2.48.1 > >
diff --git a/Documentation/admin-guide/pm/intel_idle.rst b/Documentation/admin-guide/pm/intel_idle.rst index 39bd6ecce7de..5940528146eb 100644 --- a/Documentation/admin-guide/pm/intel_idle.rst +++ b/Documentation/admin-guide/pm/intel_idle.rst @@ -192,11 +192,19 @@ even if they have been enumerated (see :ref:`cpu-pm-qos` in Documentation/admin-guide/pm/cpuidle.rst). Setting ``max_cstate`` to 0 causes the ``intel_idle`` initialization to fail. -The ``no_acpi`` and ``use_acpi`` module parameters (recognized by ``intel_idle`` -if the kernel has been configured with ACPI support) can be set to make the -driver ignore the system's ACPI tables entirely or use them for all of the -recognized processor models, respectively (they both are unset by default and -``use_acpi`` has no effect if ``no_acpi`` is set). +The ``no_acpi``, ``use_acpi`` and ``no_native`` module parameters are +recognized by ``intel_idle`` if the kernel has been configured with ACPI +support. In the case that ACPI is not configured these flags have no impact +on functionality. + +``no_acpi`` - Do not use ACPI at all. Only native mode is available, no +ACPI mode. + +``use_acpi`` - No-op in ACPI mode, the driver will consult ACPI tables for +C-states on/off status in native mode. + +``no_native`` - Work only in ACPI mode, no native mode available (ignore +all custom tables). The value of the ``states_off`` module parameter (0 by default) represents a list of idle states to be disabled by default in the form of a bitmask. diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index 118fe1d37c22..b0be5ef43ffc 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -1695,6 +1695,10 @@ static bool force_use_acpi __read_mostly; /* No effect if no_acpi is set. */ module_param_named(use_acpi, force_use_acpi, bool, 0444); MODULE_PARM_DESC(use_acpi, "Use ACPI _CST for building the idle states list"); +static bool no_native __read_mostly; /* No effect if no_acpi is set. */ +module_param_named(no_native, no_native, bool, 0444); +MODULE_PARM_DESC(no_native, "Ignore cpu specific (native) idle states in lieu of ACPI idle states"); + static struct acpi_processor_power acpi_state_table __initdata; /** @@ -1834,6 +1838,11 @@ static bool __init intel_idle_off_by_default(unsigned int flags, u32 mwait_hint) } return true; } + +static inline bool ignore_native(void) +{ + return no_native & !no_acpi; +} #else /* !CONFIG_ACPI_PROCESSOR_CSTATE */ #define force_use_acpi (false) @@ -1843,6 +1852,7 @@ static inline bool intel_idle_off_by_default(unsigned int flags, u32 mwait_hint) { return false; } +static inline bool ignore_native(void) { return false; } #endif /* !CONFIG_ACPI_PROCESSOR_CSTATE */ /** @@ -2328,6 +2338,12 @@ static int __init intel_idle_init(void) pr_debug("MWAIT substates: 0x%x\n", mwait_substates); icpu = (const struct idle_cpu *)id->driver_data; + if (ignore_native()) { + if (icpu) { + pr_debug("ignoring native cpu idle states\n"); + icpu = NULL; + } + } if (icpu) { if (icpu->state_table) cpuidle_state_table = icpu->state_table;
Since commit 18734958e9bf ("intel_idle: Use ACPI _CST for processor models without C-state tables") the intel_idle driver has had the ability to use the ACPI _CST to populate C-states when the processor model is not recognized. However, even when the processor model is recognized (native mode) there are cases where it is useful to make the driver ignore the per cpu idle states in lieu of ACPI C-states (such as specific application performance). Add the 'no_native' module parameter to provide this functionality. Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jacob Pan <jacob.jun.pan@linux.intel.com> Cc: Len Brown <lenb@kernel.org> Cc: David Arcari <darcari@redhat.com> Cc: Artem Bityutskiy <dedekind1@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: David Arcari <darcari@redhat.com> --- v4: fix !CONFIG_ACPI_PROCESSOR_CSTATE compilation issue v3: more documentation cleanup v2: renamed parameter, cleaned up documentation Documentation/admin-guide/pm/intel_idle.rst | 18 +++++++++++++----- drivers/idle/intel_idle.c | 16 ++++++++++++++++ 2 files changed, 29 insertions(+), 5 deletions(-)