Mobile Cache Waterfall 2D: Understanding TTL and…

What is Mobile Cache Waterfall?

Mobile cache waterfall refers to a visualization technique that illustrates how data requests are processed by different levels of caching in a mobile application. This includes the app's memory (L1), disk (L2), and network tiers.

The 2D flow lane represents each request as it travels through these layers, with live occupancy grids showing current cache usage at L1 and L2.

Time-To-Live (TTL) Mechanism

TTL is a caching strategy that defines the duration for which data can be considered fresh. After this period, the data becomes stale and needs to be refreshed.

By adjusting the L1 TTL slider in the simulation, you can observe how requests are invalidated and new ones are fetched from higher tiers or the network.

live demo · related simulation● LIVE

Stale-While-Revalidate

Stale-while-revalidate is a caching technique that allows users to continue using stale data while the system fetches fresh data in the background. This reduces perceived latency and improves user experience.

The simulation's 'stale-while-revalidate' toggle demonstrates how this strategy trades off freshness for reduced hidden latency.

Impact of Network Profile

Different network profiles (WiFi, 4G, 3G) can significantly affect the performance and behavior of caching strategies. The simulation allows you to switch between these profiles to see how they impact request processing.

By triggering a cold-start or adjusting the request rate, you can observe how initial cache misses and subsequent requests are handled differently based on network conditions.

Frequently asked questions

What does L1 and L2 refer to in caching?

L1 and L2 typically represent levels of caching. L1 is usually the fastest but smallest cache, often found within the CPU or app memory, while L2 is larger and slower, such as on-disk storage.

Why use stale-while-revalidate instead of always fetching fresh data?

Stale-while-revalidate reduces perceived latency by allowing users to continue using old data while the system fetches new data. This is particularly useful in scenarios where network conditions are poor or when immediate freshness is less critical.

How does adjusting TTL affect cache performance?

Adjusting TTL can balance between cache hit rates and data freshness. A shorter TTL ensures more frequent updates but may increase the load on the network, while a longer TTL reduces network requests but risks serving outdated data.

What is the purpose of panning and zooming in the flow lane?

Panning and zooming allow you to focus on specific parts of the request processing path. This helps in understanding how different tiers and caching strategies interact at various points during a request.

Try it live

Everything above runs in your browser — open Mobile Cache Waterfall 2D: TTL & Stale-While-Revalidate and change the parameters while it is running. Nothing is installed, nothing is uploaded, the whole model lives in one tab.

▶ Open Mobile Cache Waterfall 2D: TTL & Stale-While-Revalidate simulation

Mobile Cache Waterfall 2D: Understanding TTL and Stale-While-Revalidate