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| author | Gina Dimino <gdimino@google.com> | 2021-07-15 23:27:11 +0000 |
|---|---|---|
| committer | Gerrit Code Review <noreply-gerritcodereview@google.com> | 2021-07-15 23:27:11 +0000 |
| commit | 72e0ae8d8207042452f75874221103f4f6b3014a (patch) | |
| tree | 7fa97b880b85be7de5b713d233cdc407c20b88cd /en/devices/tech/power/values.html | |
| parent | e55b3193405187e091a4ac7730ef04360ec04504 (diff) | |
| parent | fc5fc0e74df003b0ee454d3418b88cd722282c49 (diff) | |
| download | source.android.com-master.tar.gz | |
Diffstat (limited to 'en/devices/tech/power/values.html')
| -rw-r--r-- | en/devices/tech/power/values.html | 388 |
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diff --git a/en/devices/tech/power/values.html b/en/devices/tech/power/values.html deleted file mode 100644 index a2ea8388..00000000 --- a/en/devices/tech/power/values.html +++ /dev/null @@ -1,388 +0,0 @@ -<html devsite> - <head> - <title>Measuring Power Values</title> - <meta name="project_path" value="/_project.yaml" /> - <meta name="book_path" value="/_book.yaml" /> - </head> - <body> - {% include "_versions.html" %} - <!-- - Copyright 2017 The Android Open Source Project - - Licensed under the Apache License, Version 2.0 (the "License"); - you may not use this file except in compliance with the License. - You may obtain a copy of the License at - - http://www.apache.org/licenses/LICENSE-2.0 - - Unless required by applicable law or agreed to in writing, software - distributed under the License is distributed on an "AS IS" BASIS, - WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - See the License for the specific language governing permissions and - limitations under the License. - --> - - - - -<p>Device manufacturers must provide a component power profile in -<code>/frameworks/base/core/res/res/xml/power_profile.xml</code>.</p> - -<p>To determine values for power profiles, use hardware that measures the power -being used by the device and perform the various operations for which -information is needed. Measure the power use during those operations and compute -the values (deriving differences from other baseline power uses as appropriate). -</p> - -<p>As the goal of a power profile is to estimate battery drain appropriately, -power profile values are given in current (amps). The Android framework -multiplies the current by the time for which the subsystem was active and -computes the mAh value, which is then used to estimate the amount of battery -drained by the application/subsystem.</p> - -<p>Devices with Bluetooth, modem, and Wi-Fi controllers running Android 7.0 and -higher can provide additional power values obtained from chipset data.</p> - - -<h2 id="multiple-cpus">Devices with heterogeneous CPUs</h2> - -<p>The power profile for devices with CPU cores of heterogeneous architecture -must include the following additional fields: -<ul> -<li>Number of total CPUs for each cluster (expressed in cpu.clusters.cores).</li> -<li>CPU speeds supported by each cluster.</li> -<li>Active CPU power consumption for each cluster.</li> -</ul> - -<p>To differentiate between active CPU power consumption and supported CPU -speeds for clusters, append the cluster number to the name of the array. Cluster -numbers are assigned in the order of CPU cores in the kernel device tree. For -example, in a heterogeneous architecture that has two (2) clusters with four (4) -cores:</p> -<ul> -<li>cluster0 consists of cpu0-3</li> -<li>cluster1 consists of cpu4-7</li> -</ul> -<p>The Android framework uses these CPU core numbers when it reads statistics -from the <code>sysfs</code> files in: -<code>/sys/devices/system/cpu/cpu<number>/cpufreq/stats</code>. - -<p>Example of cluster CPUs and speeds:</p> - -<pre class="devsite-click-to-copy"> -<array name="cpu.active.cluster0"> -<value>200</value> -<value>300</value> -<value>400</value> -</array> -<array name="cpu.speeds.cluster0"> -<value>600000</value> -<value>800000</value> -<value>1200000</value> -</array> - -<array name="cpu.active.cluster1"> -<value>400</value> -<value>500</value> -<value>600</value> -</array> -<array name="cpu.speeds.cluster1"> -<value>800000</value> -<value>1200000</value> -<value>1400000</value> -</array> -</pre> - -<h2 id="values">Power values</h2> -<p>The following table describes available power value settings. To view the -sample file in AOSP, see -<a href="https://android.googlesource.com/platform/frameworks/base/+/master/core/res/res/xml/power_profile.xml">power_profile.xml</a>.</p> - -<table> -<tr> - <th>Name</th> - <th>Description</th> - <th>Example Value</th> - <th>Notes</th> -</tr> - -<tr> - <td>ambient.on</td> - <td>Additional power used when screen is in doze/ambient/always-on mode instead of off.</td> - <td>around 100 mA</td> - <td> - </td> -</tr> - -<tr> - <td>screen.on</td> - <td>Additional power used when screen is turned on at minimum brightness.</td> - <td>200 mA</td> - <td>Includes touch controller and display backlight. At 0 brightness, not the - Android minimum which tends to be 10 or 20%.</td> -</tr> - -<tr> - <td>screen.full</td> - <td>Additional power used when screen is at maximum brightness, compared to - screen at minimum brightness.</td> - <td>100 mA-300 mA</td> - <td>A fraction of this value (based on screen brightness) is added to the - screen.on value to compute the power usage of the screen.</td> -</tr> - -<tr> - <td>wifi.on</td> - <td>Additional power used when Wi-Fi is turned on but not receiving, - transmitting, or scanning.</td> - <td>2 mA</td> - <td> - </td> -</tr> - -<tr> - <td>wifi.active</td> - <td>Additional power used when transmitting or receiving over Wi-Fi.</td> - <td>31 mA</td> - <td> - </td> -</tr> - -<tr> - <td>wifi.scan</td> - <td>Additional power used when Wi-Fi is scanning for access points.</td> - <td>100 mA</td> - <td> - </td> -</tr> - -<tr> - <td>audio</td> - <td>Additional power used when audio decoding/encoding via DSP.</td> - <td>around 10 mA</td> - <td>Used for DSP audio.</td> -</tr> - -<tr> - <td>video</td> - <td>Additional power used when video decoding via DSP.</td> - <td>around 50 mA</td> - <td>Used for DSP video.</td> -</tr> - -<tr> - <td>camera.avg</td> - <td>Average power use by the camera subsystem for a typical camera - application.</td> - <td>600 mA</td> - <td>Intended as a rough estimate for an application running a preview - and capturing approximately 10 full-resolution pictures per minute.</td> -</tr> - -<tr> - <td>camera.flashlight</td> - <td>Average power used by the camera flash module when on.</td> - <td>200 mA</td> - <td> - </td> -</tr> - -<tr> - <td>gps.signalqualitybased</td> - <td>Additional power used by GPS based on signal strength. This is a multi-value entry, - one per signal strength, from weakest to strongest.</td> - <td> 30 mA, 10 mA </td> - <td> - </td> -</tr> - -<tr> - <td>gps.on</td> - <td>Additional power used when GPS is acquiring a signal.</td> - <td>50 mA</td> - <td> - </td> -</tr> - -<tr> - <td>radio.active</td> - <td>Additional power used when cellular radio is transmitting/receiving.</td> - <td>100 mA-300 mA</td> - <td> - </td> -</tr> - -<tr> - <td>radio.scanning</td> - <td>Additional power used when cellular radio is paging the tower.</td> - <td>1.2 mA</td> - <td> - </td> -</tr> - -<tr> - <td>radio.on</td> - <td>Additional power used when the cellular radio is on. This is a multi-value entry, - one per signal strength (no signal, weak, moderate, strong).</td> - <td>1.2 mA</td> - <td>Some radios boost power when they search for a cell tower and do not - detect a signal. Values can be the same or decrease with increasing signal - strength. If you provide only one value, the same value is used for all - strengths. If you provide two values, the first is used for no-signal, the - second value is used for all other strengths, and so on.</td> -</tr> - -<tr> - <td>bluetooth.controller.idle</td> - <td>Average current draw (mA) of the Bluetooth controller when idle.</td> - <td> - </td> - <td rowspan=4>These values are not estimated, but taken from the data sheet of - the controller. If there are multiple receive or transmit states, the average - of those states is taken. In addition, the system now collects data for - <a href="#le-bt-scans">Low Energy (LE) and Bluetooth scans</a>.<br><br>Android - 7.0 and later no longer use the Bluetooth power values for bluetooth.active - (used when playing audio via Bluetooth A2DP) and bluetooth.on (used when - Bluetooth is on but idle).</td> -</tr> - -<tr> - <td>bluetooth.controller.rx</td> - <td>Average current draw (mA) of the Bluetooth controller when receiving.</td> - <td> - </td> -</tr> - -<tr> - <td>bluetooth.controller.tx</td> - <td>Average current draw (mA) of the Bluetooth controller when transmitting.</td> - <td> - </td> -</tr> - -<tr> - <td>bluetooth.controller.voltage</td> - <td>Average operating voltage (mV) of the Bluetooth controller.</td> - <td> - </td> -</tr> - -<tr> - <td>modem.controller.sleep</td> - <td> Average current draw (mA) of the modem controller when asleep.</td> - <td> 0 mA </td> - <td rowspan=5>These values are not estimated, but taken from the data sheet of the controller. - If there are multiple receive states, the average of those states is taken. If there are - multiple transmit states, specifying a value for each transmit state is supported - starting in Android {{ androidPVersionNumber}}.</td> -</tr> - -<tr> - <td>modem.controller.idle</td> - <td>Average current draw (mA) of the modem controller when idle.</td> - <td> - </td> -</tr> - -<tr> - <td>modem.controller.rx</td> - <td>Average current draw (mA) of the modem controller when receiving.</td> - <td> - </td> -</tr> - -<tr> - <td>modem.controller.tx</td> - <td>Average current draw (mA) of the modem controller when transmitting at different RF power - levels. This is a multi-value entry with one value per transmit power level.</td> - <td> 100 mA, 200 mA, 300 mA, 400 mA, 500 mA </td> -</tr> - -<tr> - <td>modem.controller.voltage</td> - <td>Average operating voltage (mV) of the modem controller.</td> - <td> - </td> -</tr> - -<tr> - <td>wifi.controller.idle</td> - <td>Average current draw (mA) of the Wi-Fi controller when idle.</td> - <td> - </td> - <td rowspan=4>These values are not estimated, but taken from the data sheet of - the controller. If there are multiple receive or transmit states, the average - of those states is taken.</td> -</tr> - -<tr> - <td>wifi.controller.rx</td> - <td>Average current draw (mA) of the Wi-Fi controller when receiving.</td> - <td> - </td> -</tr> - -<tr> - <td>wifi.controller.tx</td> - <td>Average current draw (mA) of the Wi-Fi controller when transmitting.</td> - <td> - </td> -</tr> - -<tr> - <td>wifi.controller.voltage</td> - <td>Average operating voltage (mV) of the Wi-Fi controller.</td> - <td> - </td> -</tr> - -<tr> - <td>cpu.speeds</td> - <td>This is a multi-value entry that lists each possible CPU speed in KHz.</td> - <td>125000 KHz, 250000 KHz, 500000 KHz, 1000000 KHz, 1500000 KHz</td> - <td>The number and order of entries must correspond to the mA entries in - cpu.active.</td> -</tr> - -<tr> - <td>cpu.idle</td> - <td>Total power drawn by the system when CPUs (and the SoC) are in system - suspend state.</td> - <td>3 mA</td> - <td> - </td> -</tr> - -<tr> - <td>cpu.awake</td> - <td>Additional power used when CPUs are in scheduling idle state - (kernel idle loop); system is not in system suspend state.</td> - <td>50 mA</td> - <td>Your platform might have more than one idle state in use with differing - levels of power consumption; choose a representative idle state for longer - periods of scheduler idle (several milliseconds). Examine the power graph on - your measurement equipment and choose samples where the CPU is at its lowest - consumption, discarding higher samples where the CPU exited idle.</td> -</tr> - -<tr> - <td>cpu.active</td> - <td>Additional power used by CPUs when running at different speeds.</td> - <td>100 mA, 120 mA, 140 mA, 160 mA, 200 mA</td> - <td>Value represents the power used by the CPU rails when running at different - speeds. Set the max speed in the kernel to each of the allowed speeds and peg - the CPU at that speed. The number and order of entries correspond to the - number and order of entries in cpu.speeds.</td> -</tr> - -<tr> - <td>cpu.clusters.cores</td> - <td>Number of cores each CPU cluster contains.</td> - <td>4, 2</td> - <td>Required only for devices with <a href="#multiple-cpus">heterogeneous CPU - architectures</a>. Number of entries and order should match the number of - cluster entries for the cpu.active and cpu.speeds. The first entry represents - the number of CPU cores in cluster0, the second entry represents the number of - CPU cores in cluster1, and so on.</td> -</tr> - -<tr> - <td>battery.capacity</td> - <td>Total battery capacity in mAh.</td> - <td>3000 mAh</td> - <td> - </td> -</tr> - -</table> - -<h2 id="le-bt-scans">Low Energy (LE) and Bluetooth scans</h2> -<p>For devices running Android 7.0, the system collects data for Low Energy (LE) -scans and Bluetooth network traffic (such as RFCOMM and L2CAP) and associates -these activities with the initiating application. Bluetooth scans are associated -with the application that initiated the scan, but batch scans are not (and -are instead associated with the Bluetooth application). For an application -scanning for N milliseconds, the cost of the scan is N milliseconds of rx time -and N milliseconds of tx time; all leftover controller time is assigned to -network traffic or the Bluetooth application.</p> - - </body> -</html> |