. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 6.5 Coroutines and concurrency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 6.6 Integration are almost as simple as synchronous code, but without the expense of a thread. They also make concurrency easier to reason about by reducing the number of places where a context switch can happen. Example: from tornado import gen, httpclient, queues base_url = "http://www.tornadoweb.org/en/stable/" concurrency = 10 (continues on next page) 20 Chapter 6. DocumentationTornado Documentation, Release 6.5.1

IOStream connection factory tornado.tcpserver — Basic IOStream-based TCP server Coroutines and concurrency tornado.gen — Generator-based coroutines tornado.locks – Synchronization primitives tornado.queues are almost as simple as synchronous code, but without the expense of a thread. They also make concurrency easier [https://glyph.twistedmatrix.com/2014/02/unyielding.html] to reason about by reducing the from tornado import gen, httpclient, queues base_url = "http://www.tornadoweb.org/en/stable/" concurrency = 10 async def get_links_from_url(url): """Download the page at `url` and parse it for links

good monitoring tools in place.  It is coded in a way that resists hard-to-find defects like concurrency errors. Build Versus Buy Everyone knows that in every case under the sun, in any example one

出现的特定情况，不正确的代码会直接编 译失败并提供解释问题的错误信息。因此，你可以在开发时修复代码，而不是在部署到生产环 境后修复代码。我们给 Rust 的这一部分起了一个绰号无畏并发（fearless concurrency）。无畏 并发令你的代码免于出现诡异的 bug 并可以轻松重构且无需担心会引入新的 bug。 注意：出于简洁的考虑，我们将很多问题归类为并发，而不是更准确的区分并发和/或 并行。对于本章，当我们谈到并发时，请自行脑内替换为 375/562Rust 程序设计语言 简体中文版 这正是 Rust 的 async 抽象所提供的。不过在讲解它们在实践中如何工作之前，让我们稍微绕 个远路来了解一下并行（parallelism）和并发（concurrency）的区别。 并行与并发 在上一章中，我们大致将并行和并发视为可以互换的概念。但现在我们需要更加精确地区分它 们，因为它们的区别将在实际工作中显现出来。 思考一下不同的团队分割方法来开发 forget”）；它们没有原生等同于 future 的机制，所以它们简单地运行到结束 而不会被中断，除非操作系统本身介入。也就是说，它们没有像 future 那样内建任务内并发 （intratask concurrency）支持。Rust 中的线程也没有提供取消机制 – 本章虽未明确讨论此 主题，但当我们结束一个 future 时，其状态能够被正确清理就隐含了这一事实。 这些限制也使得线程比 future

string itself does not introduce any concurrency problems even if it is printed in multiple Julia tasks. However, if print methods on a captured value can have a concurrency issue when invoked without synchronizations want to call a blocking C function without causing the current julia thread to become blocked. Concurrency is limited by size of the libuv thread pool, which defaults to 4 threads but can be increased 1.0 or higher) is required.CHAPTER 102. DEVELOPING/DEBUGGING JULIA’S C CODE 1637 Reproducing concurrency bugs with rr rr simulates a single-threaded machine by default. In order to debug concurrent code

string itself does not introduce any concurrency problems even if it is printed in multiple Julia tasks. However, if print methods on a captured value can have a concurrency issue when invoked without synchronizations want to call a blocking C function without causing the current julia thread to become blocked. Concurrency is limited by size of the libuv thread pool, which defaults to 4 threads but can be increased 1.0 or higher) is required.CHAPTER 102. DEVELOPING/DEBUGGING JULIA’S C CODE 1637 Reproducing concurrency bugs with rr rr simulates a single-threaded machine by default. In order to debug concurrent code

string itself does not introduce any concurrency problems even if it is printed in multiple Julia tasks. However, if print methods on a captured value can have a concurrency issue when invoked without synchronizations want to call a blocking C function without causing the current julia thread to become blocked. Concurrency is limited by size of the libuv thread pool, which defaults to 4 threads but can be increased 1.0 or higher) is required.CHAPTER 106. DEVELOPING/DEBUGGING JULIA'S C CODE 1946 Reproducing concurrency bugs with rr rr simulates a single-threaded machine by default. In order to debug concurrent code

string itself does not introduce any concurrency problems even if it is printed in multiple Julia tasks. However, if print methods on a captured value can have a concurrency issue when invoked without synchronizations want to call a blocking C function without causing the current julia thread to become blocked. Concurrency is limited by size of the libuv thread pool, which defaults to 4 threads but can be increased 1.0 or higher) is required.CHAPTER 106. DEVELOPING/DEBUGGING JULIA'S C CODE 1946 Reproducing concurrency bugs with rr rr simulates a single-threaded machine by default. In order to debug concurrent code

string itself does not introduce any concurrency problems even if it is printed in multiple Julia tasks. However, if print methods on a captured value can have a concurrency issue when invoked without synchronizations want to call a blocking C function without causing the current julia thread to become blocked. Concurrency is limited by size of the libuv thread pool, which defaults to 4 threads but can be increased 1.0 or higher) is required.CHAPTER 106. DEVELOPING/DEBUGGING JULIA'S C CODE 1946 Reproducing concurrency bugs with rr rr simulates a single-threaded machine by default. In order to debug concurrent code

string itself does not introduce any concurrency problems even if it is printed in multiple Julia tasks. However, if print methods on a captured value can have a concurrency issue when invoked without synchronizations want to call a blocking C function without causing the current julia thread to become blocked. Concurrency is limited by size of the libuv thread pool, which defaults to 4 threads but can be increased 1.0 or higher) is required.CHAPTER 107. DEVELOPING/DEBUGGING JULIA'S C CODE 1999 Reproducing concurrency bugs with rr rr simulates a single-threaded machine by default. In order to debug concurrent code