Link Search Menu Expand Document

Runtime Performance

Test 1: iOS, Replaying a Single Haptic Clip

This test loads a 1 second, 4 KByte, high-resolution, frequency-modulated haptic clip and plays it 50 times.

Phones Tested

iPhone 8, iPhone 11 Pro and iPhone SE (v2).

Memory Usage

Memory Usage

Step Memory Usage
Application Size 11.8 MByte
Framework Instantiation 300 KByte
Read Haptic 100 KByte
Load Haptic 0 KByte
Play Haptic 1st 0 KByte
Play Haptic 49x 🔥100 KByte

The Studio framework for iOS is allocating and freeing memory efficiently for Init, Load, and Play.

🔥Over 50 plays of a single haptic, we are seeing a memory increase of 100 KByte. This is under investigation.

CPU

CPU Profiling

iPhone 11 Pro and SE: instantiation of the Studio framework for iOS and loading of the haptic file uses 1% of the CPU for a few milliseconds. Subsequent firings of haptics are very efficient.

iPhone 8: instantiation of the Studio framework for iOS and loading of the haptic file uses 2% of the CPU for a few milliseconds. Subsequent firings average at 1.5% CPU usage.

Test 2: iOS, Loading and Playing Multiple Haptics

This test loads and plays multiple 1 second, 4 KByte, high-resolution, frequency-modulated clips every 2 seconds for 5 minutes. This test uses a collection of different haptic files, and each iteration of playback naively loads the file from disk. There is no caching of files.

NOTE: We consider this a fairly heavy test: we don’t expect this to be a typical use case. Most applications would have shorter-duration haptic effects and/or wider intervals, but this is definitely a case we can support.

Phones Tested

iPhone 8, iPhone 11 Pro and iPhone SE (v2).

Memory

Memory Profiling

After the application is loaded into memory, memory for multiple clip playback is allocated and freed correctly over time.

CPU

CPU Profiling

iPhone 11 Pro and SE never goes beyond 1% CPU usage.

iPhone 8 never goes beyond 2% CPU usage.

Test 3: iOS, Real Time Audio to Haptics

Currently Under Test

Energy Usage

Currently Under Test

Energy Usages

Both the Studio framework for iOS and Apple Core Haptics are already fairly CPU-efficient and make almost no use of I/O, GPU, networking, graphics rendering, etc. So, the output we recorded is completely expected: haptic playback should have a low energy profile. However, the energy usage of the Taptic Engine, itself, is not reported by the instruments.

From our experience designing and manufacturing high-quality haptic actuators (such as the Lofelt L5), we know they require far less power to run than a CPU or high-resolution display. We are know that continued use of haptics on a phone for a substantial period of time will not be “free” in terms of power consumption, but the demand will be minimal in comparison to the energy consumption taken up by CPU, GPU, networking, and disk I/O tasks.

We are currently investigating this more thoroughly with extensive, long running tests. We expect to publish these findings soon.

< Prev Next >


Copyright © 2020 Lofelt GmbH. All rights reserved.