geopm_pio_sst(7) -- Signals and controls for Intel Speed Select Technology
==========================================================================
Description
-----------
The SSTIOGroup implements the :doc:`geopm::IOGroup(3)
<geopm::IOGroup.3>` interface to provide hardware signals
and controls for key Intel Speed Select Technology features on
supported Intel platforms with Linux Kernel versions >=5.3
SST-CP: Core Power
^^^^^^^^^^^^^^^^^^^
SST Core Power feature enables the user to specify priority of cores
for power distribution in a power-constrained scenario. Cores are
assigned to different Class Level of Service (CLOS). Each CLOS has a
defined min/max frequency and weight, which determines how the
frequency is allocated.
SST-TF: Turbo Frequency
^^^^^^^^^^^^^^^^^^^^^^^
SST Turbo Frequency feature enables the user to dynamically set
different turbo ratio limits for different cores. Cores are specified
as high-priority or low-priority via the SST-CP feature. Cores in CLOS
0 or 1 are high priority and can reach higher than the all-core turbo
ratio limit when there is sufficient power headroom. Cores in CLOS 2
or 3 are constrained below the all-core turbo ratio limit. This
feature only works when SST-CP is enabled.
Signals
-------
System Info
^^^^^^^^^^^
``SST::CONFIG_LEVEL:LEVEL``
Returns the system's configuration level (SST-PP feature)
* **Aggregation**: expect_same
* **Domain**: package
* **Format**: double
* **Unit**: n/a
``SST::COREPRIORITY_SUPPORT:CAPABILITIES``
Returns 1 if SST-CP feature is supported, 0 if
unsupported.
* **Aggregation**: sum
* **Domain**: package
* **Format**: double
* **Unit**: n/a
``SST::HIGHPRIORITY_NCORES:n``
Returns the count of high priority turbo frequency
cores in bucket n. Buckets 0 - 7 are supported. Buckets are defined
by the number of high priority cores (cores in CLOS 0 or 1), and
they determine the frequencies that are obtainable by those
cores. Generally, if there are fewer high priority cores, the
increase in turbo frequency limit is greater.
* **Aggregation**: expect_same
* **Domain**: package
* **Format**: double
* **Unit**: n/a
``SST::HIGHPRIORITY_FREQUENCY_SSE:n``
Returns the high priority turbo frequency for bucket
*n* at the SSE license level.
* **Aggregation**: expect_same
* **Domain**: package
* **Format**: double
* **Unit**: n/a
``SST::HIGHPRIORITY_FREQUENCY_AVX2:n``
Returns the high priority turbo frequency for bucket
*n* at the AVX2 license level.
* **Aggregation**: expect_same
* **Domain**: package
* **Format**: double
* **Unit**: n/a
``SST::HIGHPRIORITY_FREQUENCY_AVX512:n``
Returns the high priority turbo frequency for bucket
n at the AVX512 license level.
* **Aggregation**: expect_same
* **Domain**: package
* **Format**: double
* **Unit**: n/a
``SST::LOWPRIORITY_FREQUENCY:[SSE|AVX2|AVX512]``
Returns the low-priority turbo frequency of the
specified license level. Note these frequencies do not change based
on the number of high priority cores.
* **Aggregation**: expect_same
* **Domain**: package
* **Format**: double
* **Unit**: n/a
``SST::TURBOFREQ_SUPPORT:SUPPORTED``
Returns 1 if SST-TF feature is supported, 0 if
unsupported.
* **Aggregation**: sum
* **Domain**: package
* **Format**: double
* **Unit**: n/a
Configuration
"""""""""""""
``SST::TURBO_ENABLE:ENABLE``
Returns 1 if SST-TF feature is enabled, 0 if
disabled.
* **Aggregation**: sum
* **Domain**: package
* **Format**: double
* **Unit**: n/a
``SST::COREPRIORITY_ENABLE:ENABLE``
Returns 1 if SST-CP feature is enabled, 0 if
disabled.
* **Aggregation**: expect_same
* **Domain**: package
* **Format**: double
* **Unit**: n/a
``SST::COREPRIORITY:ASSOCIATION``
Returns the CPU's assigned CLOS.
* **Aggregation**: expect_same
* **Domain**: core
* **Format**: double
* **Unit**: n/a
``SST::COREPRIORITY:n:PRIORITY``
Returns proportional priority for CLOS *n*. A lower
value indicates a higher importance. Priority ranges from 0-1 and is
used to distribute power amongst cores.
* **Aggregation**: expect_same
* **Domain**: package
* **Format**: double
* **Unit**: n/a
``SST::COREPRIORITY:n:FREQUENCY_MIN``
Returns the minimum frequency of CLOS *n*. Given
sufficient power headroom, all cores will receive this minimum
frequency before any remaining power is distributed.
* **Aggregation**: expect_same
* **Domain**: package
* **Format**: double
* **Unit**: n/a
``SST::COREPRIORITY:n:FREQUENCY_MAX``
Returns the maximum frequency of CLOS *n*. Power will
not be distributed to cores beyond this maximum frequency.
* **Aggregation**: expect_same
* **Domain**: package
* **Format**: double
* **Unit**: n/a
Controls
--------
``SST::TURBO_ENABLE``
Enable SST-TF feature. Enabling SST-TF also causes SST-CP to be enabled.
* **Aggregation**: sum
* **Domain**: package
* **Format**: double
* **Unit**: n/a
``SST::COREPRIORITY_ENABLE``
Enable SST-CP feature. Disabling SST-CP also causes SST-TF to be disabled.
* **Aggregation**: sum
* **Domain**: package
* **Format**: double
* **Unit**: n/a
``SST::COREPRIORITY:ASSOCIATION``
Assign a core to a CLOS.
* **Aggregation**: expect_same
* **Domain**: core
* **Format**: double
* **Unit**: n/a
``SST::COREPRIORITY:n:PRIORITY``
Set proportional priority for CLOS *n*. A lower value
indicates a higher importance. Weight ranges from 0-1 and is used to
distribute power amongst cores.
* **Aggregation**: expect_same
* **Domain**: package
* **Format**: double
* **Unit**: n/a
``SST::COREPRIORITY:n:FREQUENCY_MIN``
Set the minimum frequency of CLOS *n*. Given
sufficient power headroom, all cores will receive this minimum
frequency before any remaining power is distributed.
* **Aggregation**: expect_same
* **Domain**: package
* **Format**: double
* **Unit**: n/a
``SST::COREPRIORITY:n:FREQUENCY_MAX``
Set the maximum frequency of CLOS *n*. Power will not
be distributed to cores beyond this maximum frequency.
* **Aggregation**: expect_same
* **Domain**: package
* **Format**: double
* **Unit**: n/a
Example
-------
The following example uses geopmread and geopmwrite command-line
tools. These steps can also be followed within an agent.
Enabling SST-TF
^^^^^^^^^^^^^^^
* Enable SST-CP:
``geopmwrite SST::COREPRIORITY_ENABLE:ENABLE board 0 1``
* Enable SST-TF:
``geopmwrite SST::TURBO_ENABLE:ENABLE board 0 1``
* Ensure that the turbo ratio limit MSR has been overwritten to allow
higher all-core turbo frequencies.
``geopmwrite MSR::TURBO_RATIO_LIMIT:MAX_RATIO_LIMIT_0 board 0 255e8``
``geopmwrite MSR::TURBO_RATIO_LIMIT:MAX_RATIO_LIMIT_1 board 0 255e8``
...
``geopmwrite MSR::TURBO_RATIO_LIMIT:MAX_RATIO_LIMIT_7 board 0 255e8``
Configuring CLOS
^^^^^^^^^^^^^^^^
* Set the weight 0-1. Lower weight indicates higher priority. CLOS
priority decreases as the CLOS number increases and weights should
indicate that to achieve decent behavior.
``geopmwrite SST::COREPRIORITY:0:PRIORITY board 0 0``
``geopmwrite SST::COREPRIORITY:1:PRIORITY board 0 0.34``
``geopmwrite SST::COREPRIORITY:2:PRIORITY board 0 0.67``
``geopmwrite SST::COREPRIORITY:3:PRIORITY board 0 1``
* Set the min and max frequencies per CLOS.
``geopmwrite SST::COREPRIORITY:0:MIN_FREQUENCY board 0 1.5e9``
``geopmwrite SST::COREPRIORITY:0:MAX_FREQUENCY board 0 3.6e9``
Setting Core Priorities
^^^^^^^^^^^^^^^^^^^^^^^
To assign core 3 to CLOS 1:
``geopmwrite SST::COREPRIORITY:ASSOCIATION core 3 1``
See Also
--------
:doc:`geopm(7) <geopm.7>`,
:doc:`geopm::IOGroup(3) <geopm::IOGroup.3>`,
:doc:`geopmwrite(1) <geopmwrite.1>`,
:doc:`geopmread(1) <geopmread.1>`,
:doc:`geopm::Agg(3) <geopm::Agg.3>`