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As I mentioned in #1536: * Break into segments at approximately the places @fw-immunant put breaks * Move all of the files into `src/concurrency` * Add timings and segment/session metadata so course outlines appear There's room for more work here, including some additional feedback from @fw-immunant after the session I observed, but let's do one step at a time :)
35 lines
1.1 KiB
Markdown
35 lines
1.1 KiB
Markdown
---
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session: Afternoon
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target_minutes: 180
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---
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# Welcome
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"Async" is a concurrency model where multiple tasks are executed concurrently by
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executing each task until it would block, then switching to another task that is
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ready to make progress. The model allows running a larger number of tasks on a
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limited number of threads. This is because the per-task overhead is typically
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very low and operating systems provide primitives for efficiently identifying
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I/O that is able to proceed.
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Rust's asynchronous operation is based on "futures", which represent work that
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may be completed in the future. Futures are "polled" until they signal that they
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are complete.
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Futures are polled by an async runtime, and several different runtimes are
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available.
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## Comparisons
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- Python has a similar model in its `asyncio`. However, its `Future` type is
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callback-based, and not polled. Async Python programs require a "loop",
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similar to a runtime in Rust.
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- JavaScript's `Promise` is similar, but again callback-based. The language
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runtime implements the event loop, so many of the details of Promise
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resolution are hidden.
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## Schedule
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{{%session outline}}
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