| Derived Measurements |
| ===================== |
| |
| |
| The ``DerivedMeasurements`` API provides a consistent way of performing post |
| processing on a provided :class:`MeasurementCsv` file. |
| |
| Example |
| ------- |
| |
| The following example shows how to use an implementation of a |
| :class:`DerivedMeasurement` to obtain a list of calculated ``DerivedMetric``'s. |
| |
| .. code-block:: ipython |
| |
| # Import the relevant derived measurement module |
| # in this example the derived energy module is used. |
| In [1]: from devlib import DerivedEnergyMeasurements |
| |
| # Obtain a MeasurementCsv file from an instrument or create from |
| # existing .csv file. In this example an existing csv file is used which was |
| # created with a sampling rate of 100Hz |
| In [2]: from devlib import MeasurementsCsv |
| In [3]: measurement_csv = MeasurementsCsv('/example/measurements.csv', sample_rate_hz=100) |
| |
| # Process the file and obtain a list of the derived measurements |
| In [4]: derived_measurements = DerivedEnergyMeasurements.process(measurement_csv) |
| |
| In [5]: derived_measurements |
| Out[5]: [device_energy: 239.1854075 joules, device_power: 5.5494089227 watts] |
| |
| API |
| --- |
| |
| Derived Measurements |
| ~~~~~~~~~~~~~~~~~~~~ |
| |
| .. class:: DerivedMeasurements |
| |
| The ``DerivedMeasurements`` class provides an API for post-processing |
| instrument output offline (i.e. without a connection to the target device) to |
| generate additional metrics. |
| |
| .. method:: DerivedMeasurements.process(measurement_csv) |
| |
| Process a :class:`MeasurementsCsv`, returning a list of |
| :class:`DerivedMetric` and/or :class:`MeasurementsCsv` objects that have been |
| derived from the input. The exact nature and ordering of the list memebers |
| is specific to indivial 'class'`DerivedMeasurements` implementations. |
| |
| .. method:: DerivedMeasurements.process_raw(\*args) |
| |
| Process raw output from an instrument, returnin a list :class:`DerivedMetric` |
| and/or :class:`MeasurementsCsv` objects that have been derived from the |
| input. The exact nature and ordering of the list memebers is specific to |
| indivial 'class'`DerivedMeasurements` implewmentations. |
| |
| The arguents to this method should be paths to raw output files generated by |
| an instrument. The number and order of expected arguments is specific to |
| particular implmentations. |
| |
| |
| Derived Metric |
| ~~~~~~~~~~~~~~ |
| |
| .. class:: DerivedMetric |
| |
| Represents a metric derived from previously collected ``Measurement``s. |
| Unlike, a ``Measurement``, this was not measured directly from the target. |
| |
| |
| .. attribute:: DerivedMetric.name |
| |
| The name of the derived metric. This uniquely defines a metric -- two |
| ``DerivedMetric`` objects with the same ``name`` represent to instances of |
| the same metric (e.g. computed from two different inputs). |
| |
| .. attribute:: DerivedMetric.value |
| |
| The ``numeric`` value of the metric that has been computed for a particular |
| input. |
| |
| .. attribute:: DerivedMetric.measurement_type |
| |
| The ``MeasurementType`` of the metric. This indicates which conceptual |
| category the metric falls into, its units, and conversions to other |
| measurement types. |
| |
| .. attribute:: DerivedMetric.units |
| |
| The units in which the metric's value is expressed. |
| |
| |
| Available Derived Measurements |
| ------------------------------- |
| |
| .. note:: If a method of the API is not documented for a particular |
| implementation, that means that it s not overriden by that |
| implementation. It is still safe to call it -- an empty list will be |
| returned. |
| |
| Energy |
| ~~~~~~ |
| |
| .. class:: DerivedEnergyMeasurements |
| |
| The ``DerivedEnergyMeasurements`` class is used to calculate average power and |
| cumulative energy for each site if the required data is present. |
| |
| The calculation of cumulative energy can occur in 3 ways. If a |
| ``site`` contains ``energy`` results, the first and last measurements are extracted |
| and the delta calculated. If not, a ``timestamp`` channel will be used to calculate |
| the energy from the power channel, failing back to using the sample rate attribute |
| of the :class:`MeasurementCsv` file if timestamps are not available. If neither |
| timestamps or a sample rate are available then an error will be raised. |
| |
| |
| .. method:: DerivedEnergyMeasurements.process(measurement_csv) |
| |
| This will return total cumulative energy for each energy channel, and the |
| average power for each power channel in the input CSV. The output will contain |
| all energy metrics followed by power metrics. The ordering of both will match |
| the ordering of channels in the input. The metrics will by named based on the |
| sites of the coresponding channels according to the following patters: |
| ``"<site>_total_energy"`` and ``"<site>_average_power"``. |
| |
| |
| FPS / Rendering |
| ~~~~~~~~~~~~~~~ |
| |
| .. class:: DerivedGfxInfoStats(drop_threshold=5, suffix='-fps', filename=None, outdir=None) |
| |
| Produces FPS (frames-per-second) and other dervied statistics from |
| :class:`GfxInfoFramesInstrument` output. This takes several optional |
| parameters in creation: |
| |
| :param drop_threshold: FPS in an application, such as a game, which this |
| processor is primarily targeted at, cannot reasonably |
| drop to a very low value. This is specified to this |
| threhold. If an FPS for a frame is computed to be |
| lower than this treshold, it will be dropped on the |
| assumption that frame rednering was suspended by the |
| system (e.g. when idling), or there was some sort of |
| error, and therefore this should be used in |
| performance calculations. defaults to ``5``. |
| :param suffix: The name of the gerated per-frame FPS csv file will be |
| derived from the input frames csv file by appending this |
| suffix. This cannot be specified at the same time as |
| a ``filename``. |
| :param filename: As an alternative to the suffix, a complete file name for |
| FPS csv can be specified. This cannot be used at the same |
| time as the ``suffix``. |
| :param outdir: By default, the FPS csv file will be placed in the same |
| directory as the input frames csv file. This can be changed |
| by specifying an alternate directory here |
| |
| .. warning:: Specifying both ``filename`` and ``oudir`` will mean that exactly |
| the same file will be used for FPS output on each invocation of |
| ``process()`` (even for different inputs) resulting in previous |
| results being overwritten. |
| |
| .. method:: DerivedGfxInfoStats.process(measurement_csv) |
| |
| Process the fames csv generated by :class:`GfxInfoFramesInstrument` and |
| returns a list containing exactly three entries: :class:`DerivedMetric`\ s |
| ``fps`` and ``total_frames``, followed by a :class:`MeasurentCsv` containing |
| per-frame FPSs values. |
| |
| .. method:: DerivedGfxInfoStats.process_raw(gfxinfo_frame_raw_file) |
| |
| As input, this takes a single argument, which should be the path to the raw |
| output file of :class:`GfxInfoFramesInstrument`. The returns stats |
| accumulated by gfxinfo. At the time of wrinting, the stats (in order) are: |
| ``janks``, ``janks_pc`` (percentage of all frames), |
| ``render_time_50th_ptile`` (50th percentile, or median, for time to render a |
| frame), ``render_time_90th_ptile``, ``render_time_95th_ptile``, |
| ``render_time_99th_ptile``, ``missed_vsync``, ``hight_input_latency``, |
| ``slow_ui_thread``, ``slow_bitmap_uploads``, ``slow_issue_draw_commands``. |
| Please see the `gfxinfo documentation`_ for details. |
| |
| .. _gfxinfo documentation: https://developer.android.com/training/testing/performance.html |
| |
| |
| .. class:: DerivedSurfaceFlingerStats(drop_threshold=5, suffix='-fps', filename=None, outdir=None) |
| |
| Produces FPS (frames-per-second) and other dervied statistics from |
| :class:`SurfaceFlingerFramesInstrument` output. This takes several optional |
| parameters in creation: |
| |
| :param drop_threshold: FPS in an application, such as a game, which this |
| processor is primarily targeted at, cannot reasonably |
| drop to a very low value. This is specified to this |
| threhold. If an FPS for a frame is computed to be |
| lower than this treshold, it will be dropped on the |
| assumption that frame rednering was suspended by the |
| system (e.g. when idling), or there was some sort of |
| error, and therefore this should be used in |
| performance calculations. defaults to ``5``. |
| :param suffix: The name of the gerated per-frame FPS csv file will be |
| derived from the input frames csv file by appending this |
| suffix. This cannot be specified at the same time as |
| a ``filename``. |
| :param filename: As an alternative to the suffix, a complete file name for |
| FPS csv can be specified. This cannot be used at the same |
| time as the ``suffix``. |
| :param outdir: By default, the FPS csv file will be placed in the same |
| directory as the input frames csv file. This can be changed |
| by specifying an alternate directory here |
| |
| .. warning:: Specifying both ``filename`` and ``oudir`` will mean that exactly |
| the same file will be used for FPS output on each invocation of |
| ``process()`` (even for different inputs) resulting in previous |
| results being overwritten. |
| |
| .. method:: DerivedSurfaceFlingerStats.process(measurement_csv) |
| |
| Process the fames csv generated by :class:`SurfaceFlingerFramesInstrument` and |
| returns a list containing exactly three entries: :class:`DerivedMetric`\ s |
| ``fps`` and ``total_frames``, followed by a :class:`MeasurentCsv` containing |
| per-frame FPSs values, followed by ``janks`` ``janks_pc``, and |
| ``missed_vsync`` metrics. |
