Microsoft/calculator

Calculator startup time increased by 40ms after version 1906

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#939 opened on Jan 17, 2020

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Area: PerformanceBugPri: 2help wantedtriage approved

Description

Calculator version 10.1906.51.0 starts up about 40ms faster than more recent versions.

The main reason for this regression is that 1906 uses WinUI version 2.0, while later versions use WinUI 2.1 or 2.2. This is convenient to verify because the last commit in the 1906 branch switches to WinUI 2.0 instead of 2.1.

How to measure

  • Build the Calculator app in the x64 Release configuration
  • Deploy the app locally using Visual Studio
  • Use my MeasureAppStartupTime tool to repeatedly start the app and measure how much time it takes to reach the "UIResponsive" event. MeasureAppStartupTime.exe -n 30 Microsoft.WindowsCalculator.Dev_8wekyb3d8bbwe!App
  • Report the average time after 30 launches

Results

I tested on a fairly high-end Core i7-8700 desktop running Windows 10 Insider Preview Build 19546. The absolute performance difference is different on different machines, but the relative difference is always measurable.

Requested assignment

Help wanted.

Contributor guide

Tech stack
cpp
Domain
performance
Issue type
performance
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Basic knowledge of Windows app developmentAbility to build and deploy with Visual StudioUnderstanding of startup time measurement
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
Investigate the commits between WinUI 2.0 and 2.1 to identify which specific changes caused the startup time increase. Use the MeasureAppStartupTime tool to compare performance. The issue provides two commit hashes to test. Look at WinUI version differences and consider if any XAML loading or initialization changes can be optimized. The repo is microsoft/calculator, and the issue is number 939.