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With the updates to development tools like Xcode 26 and Instruments, performance debugging in the iOS 26 environment has brought new challenges. Users have reported issues such as "interface lag," "slow startup," and "frame rate drops" after upgrading.

From the development phase to the production environment, using a suitable combination of debugging tools to locate, analyze, and fix performance bottlenecks is particularly important. This article will introduce how to combine multiple tools (including Kemo, Instruments, etc.) to complete performance debugging in iOS 26 from multiple functional dimensions.

I. Main Dimensions and Goals of Performance Debugging

In the iOS 26 environment, performance debugging should focus on the following dimensions:

Frame Rate and Rendering Efficiency — Monitor frame rate drops, frame skipping, and rendering latency during animations, list scrolling, and page switching.

CPU/GPU/Main Thread Blocking — Identify main thread blocking, excessive GPU compositing time, and resource concurrency contention.

Resource I/O and Network Latency — Whether file read/write, network requests, and image decoding are causing main process lag.

Startup and Switching Latency — App startup time, background switching recovery time, and UI initial rendering latency.

System load and version differences — Compare performance across different devices/system versions (e.g., iOS 25 vs iOS 26) to identify performance changes resulting from version upgrades.

These dimensions form the foundation of a performance tuning system. The next step is selecting the right combination of tools.

II. Recommended tool combinations and their responsibilities

This combination allows development teams to cover the entire process of "monitoring → analysis → comparison → optimization". KeyMob is responsible for the "high-frequency monitoring + data aggregation + comparison report" stage, while other tools provide support and in-depth analysis.

III. Practical Process: iOS 26 Performance Debugging Implementation Steps

Step 1: Device and Version Preparation

Select multiple devices (high-end/mid-range/older models) and install iOS 26 and an older system (such as iOS 25) as control groups.

Install KeyMob on each device and start automated scripts to execute a unified interaction path (such as list scrolling, page switching, resource loading).

Step 2: Baseline Monitoring and Data Acquisition

Use KeyMob to monitor frame rate, number of stutters, resource access latency, and CPU/GPU usage, recording data between the two versions and the two devices.

Simultaneously, use Instruments on the selected devices to open Time Profiler, Core Animation, and Metal series tools to detect frame rendering and main thread blocking.

Step 3: Anomaly Marking and In-depth Analysis

When KeyMob detects a sudden drop in frame rate or frequent stutters on a certain path, it automatically marks and records the resource status (CPU/GPU, I/O, network).

Then use Instruments to jump to the corresponding time period and analyze bottlenecks such as frame rendering time, layer compositing, main thread blocking, and resource access blocking.

Step 4: Cross-Version/Device Comparison Analysis

Generate comparison charts from the multi-device/multi-version data aggregated by KeyMob to identify differences in frame rate, stuttering, and latency between iOS 26 and older systems.

Analyze logs and network tools to determine if performance changes are caused by resource loading, network changes, or the operation of new system services.

Step 5: Optimization Solutions and Regression Verification

Implement optimizations for identified bottlenecks (e.g., excessive composition layers, synchronous resource loading, heavy main thread tasks, network request blocking).

Run the script again after optimization and use KeyMob + Instruments to compare changes in frame rate, stuttering, and resource access latency before and after optimization; continuously monitor user-end data in the production environment.

Optimization Suggestions and Common Pitfalls

Control the overhead of monitoring tools: frequent sampling may negatively impact performance.

Don't just look at the average frame rate: frame skipping, minimum frame rate, and response latency better reflect user experience.

The initial system rebuild/background service after upgrading to iOS 26 may cause temporary stuttering; wait until stability is achieved before comparing data. Apple Support Community: Older devices are more likely to expose performance bottlenecks; testing should focus on mid-range and low-end models.

Network/resource loading congestion is often a hidden bottleneck: use network debugging tools to troubleshoot.

Continuous monitoring is more important than a single test: rerun the test after each app update/system patch.