使用 ConfigureAwait(false) 和 Task.Run 有什么区别? [英] What are the differences between using ConfigureAwait(false) and Task.Run?

问题描述

我知道建议在库代码中为 await 使用 ConfigureAwait(false) 以便后续代码不会在调用者的执行上下文中运行，这可能是一个 UI 线程.我也明白，出于同样的原因，应该使用 await Task.Run(CpuBoundWork) 而不是 CpuBoundWork().

I understand that it's recommended to use ConfigureAwait(false) for awaits in library code so that subsequent code does not run in the caller's execution context, which could be a UI thread. I also understand that await Task.Run(CpuBoundWork) should be used instead of CpuBoundWork() for the same reason.

public async Task<HtmlDocument> LoadPage(Uri address)
{
    using (var client = new HttpClient())
    using (var httpResponse = await client.GetAsync(address).ConfigureAwait(false))
    using (var responseContent = httpResponse.Content)
    using (var contentStream = await responseContent.ReadAsStreamAsync().ConfigureAwait(false))
        return LoadHtmlDocument(contentStream); //CPU-bound
}

带有 Task.Run

的示例

public async Task<HtmlDocument> LoadPage(Uri address)
{
    using (var client = new HttpClient())
    using (var httpResponse = await client.GetAsync(address))
        return await Task.Run(async () =>
        {
            using (var responseContent = httpResponse.Content)
            using (var contentStream = await responseContent.ReadAsStreamAsync())
                return LoadHtmlDocument(contentStream); //CPU-bound
        });
}

这两种方法有什么区别?

What are the differences between these two approaches?

推荐答案

当你说 Task.Run 时，你是说你有一些 CPU 工作要做，这可能需要很长时间，所以它应该始终在线程池线程上运行.

When you say Task.Run, you are saying that you have some CPU work to do that may take a long time, so it should always be run on a thread pool thread.

当您说 ConfigureAwait(false) 时，您是说该 async 方法的其余部分不需要原始上下文.ConfigureAwait 更像是一个优化提示；它并不总是意味着延续在线程池线程上运行.

When you say ConfigureAwait(false), you are saying that the rest of that async method does not need the original context. ConfigureAwait is more of an optimization hint; it does not always mean that the continuation is run on a thread pool thread.

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