Trepn Profiler – Power-related FAQ
Q: How can I display per-rail power values?
Trepn Profiler has special power monitoring capabilities when used with some (but not all) Snapdragon MDP development hardware. This makes it possible to display the power on selected rails associated with various hardware blocks like the CPU, graphics, camera and more. To use this feature, launch Trepn Profiler and follow these steps:
1. Touch the Settings icon in the upper right and go to “Data Points.” You should see “CPU” and other power rails under POWER STATS.
2. Start by unchecking all existing checkboxes. Then touch the checkboxes for the power rails you wish to monitor.
3. Next, press the Back button and touch either “Profile System” or “Profile App.”
4. Then touch either “Graph” or “Stats.”
Trepn Profiler should now display the delta power for the hardware rails you’ve selected. If all of the EPM rails read "0", there is a problem with your device. Send an mail to firstname.lastname@example.org and request that your device is serviced.
When a Snapdragon 805 MDP tablet from Intrinsyc is idle, its average power values should be close to the following:
Battery Power 2500-3000mW
Digital Core 6-25
Internal Memory 0-35
LCD Backlight 128-450
SD Card 0.02-.2.0
Note: This are idle values. These will increase when your tablet is active. These are just estimates. Your values could be lower or highter than these.
Tip: At any time during profiling, you can press the Back button and switch between Stats or Graph views. Use Graph view to see the correlation of individual power rails to overall power consumption – or other data points like CPU Load. Use Stats view for a quick comparison of the power deltas of several different rails at once.
Q: Why don’t some devices display accurate battery power?
A: Battery power is not supported on all devices. Refer to the "Supported Device" post for a list of supported devices.
Q: Which mobile devices are capable of displaying power rail measurements?
A: Currently this feature is only supported by Snapdragon 800 (8974) MDP tablets, Snapdragon 800 (8974) or Snapdragon 801-powered MDP smartphones, Snapdragon 805 (8084) MDP tablets and Snapdragon 810 (8994) MDP tablets. The Snapdragon 810 (8994) MDP Smartphone does NOT support per-rail power.
Q: I have a Snapdragon MDP. How can I get this software?
A: You can download it here (QDN log-in required). Note: If this is your first time on the Qualcomm Developer Network, you'll need to create a new account and log-in. Anyone can create an account on the Qualcomm Developer Network.
Make sure to uninstall any old Trepn software before you install the updated version. Also, keep in mind you will only see the power rails if you have one of the following devices:
- Snapdragon 800 MDP tablet
- Snapdragon 800 MDP smartphone
- Snapdragon 801 MDP smartphone
- Snapdragon 805 MDP tablet (v1.1 hardware or later)
- Snapdragon 810 MDP tablet (810 smartphone NOT supported)
Q: I have a Snapdragon MDP tablet. How can I get this software?
A: It should be pre-installed on all Snapdragon 805 and Snapdragon 810 MDP tablets sold by Intrinsyc. Look for the Trepn icon in the Application locker.
Q: Where can I purchase a Snapdragon MDP smartphone or tablet?
A: Snapdragon MDPs are available for purchase at Intrinsyc.
Q: What are delta-based power measurements?
When Trepn starts profiling, it collects initial measurements to determine a baseline power for each of the selected rails at that time. As Trepn profiles, the value displayed for the power rail is the delta between the current power and the initial baseline power. This makes it easy to see whether your actions have resulted in an increase in power consumption.
Q: Is it possible to see absolute power values in mW?
This version of Trepn Profiler only displays power in mW for the battery. All per-rail power readings are delta-based.
Q: I’m not seeing power rails on the Settings screen. What is the problem?
First confirm you are running Trepn Profiler 5.1p or Trepn 6.0 and have one of the supported devices listed above. If the About Box says Trepn Profiler 5.1s, it means you do not have a supported device. Next, confirm that your Snapdragon MDPs has the newest software from Bsquare or Intrinsyc.
Q: What power rails are displayed on Snapdragon 800 or Snapdragon 801 MDP smartphones?
A: CPU, Graphics, LCD Backlight, Camera, Digital Core/SD Card/USB and WLAN/BT/FM.
Q: What power rails are displayed on a Snapdragon 800 MDP tablet?
A: CPU, Graphics, LCD Backlight, Camera, Audio, USB, SD Card, Internal Memory, WLAN/BT/FM, Digital Core/SD Card/USB and Codec/GPS/Wireless.
Q: What power rails are displayed on a Snapdragon 805 MDP tablet?
A: CPU, Graphics, LCD Backlight, Camera, SD Card, Internal Memory, WLAN/BT and Digital Core.
Q: What power rails are displayed on a Snapdragon 810 MDP tablet?
A: CPU (Cores 0-3), CPU (Cores 4-7), Graphics (GPU), LCD Backlight, Front Camera, Rear Camera, System Memory (RAM), Internal Memory/SD Card, Wi-Fi/Bluetooth, Sensors and USB.
Q: Why do some rails (e.g. Camera) display 0?
A: Because all non-battery power readings are delta measurements. Unless the camera is in-use, there is no change between the baseline power measurement and the current value.
Q: How can I magnify the lower power rails in Graph view?
A: Power readings in Graph view auto-scale. If one reading is much larger than others, it will effectively push down the readings of the lower rails and make them harder to read. To address this issue, slide the “Legend” to the left and touch items like Battery Power and LCD Backlight to hide them. Keep doing this until the rest of the waveforms increase in size.
Q: Why can’t I get waveforms to auto-scale even though I’ve hidden the largest values?
A: If a power spike is short enough, it’s possible you won’t see it unless you zoom in, but it can still affect the auto-scale process.
Q: Does Trepn Profiler have an impact on any of the power rail readings?
Yes. The Trepn Profiler APK consumes a fair number of CPU cycles because it is capturing a large amount of data and writing it to memory.
Q: Why do average power readings drop over time?
A: It is expected that average power values will drop over time when a hardware module is not currently in use. Refer to the Instantaneous values for a better approximation of the current power consumption. You can also switch to Graph view at any time by hitting the Back button to see a more accurate history of power consumption over time.
Q: How can I improve the accuracy of power readings on grouped rails?
A: When selecting a grouped power rail like WLAN/BT/FM, make sure to turn off the things you don’t want to test. For example, if you’re interested in measuring WLAN power usage, select the “WLAN/BT/FM” rail and turn off “Bluetooth” in Android Settings. Also make sure you don’t have the FM Radio app running.
Q: Is there a way to insert markers in my code that are displayed by Trepn?
Yes. Use Application States to insert markers into your code to help track down exactly which section of code is causing a power spike. Refer to Chapter 4 in the Trepn User Guide for more information.