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path: root/tokio/src/blocking/pool.rs
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2019-11-21runtime: cleanup and add config options (#1807)Carl Lerche
* runtime: cleanup and add config options This patch finishes the cleanup as part of the transition to Tokio 0.2. A number of changes were made to take advantage of having all Tokio types in a single crate. Also, fixes using Tokio types from `spawn_blocking`. * Many threads, one resource driver Previously, in the threaded scheduler, a resource driver (mio::Poll / timer combo) was created per thread. This was more or less fine, except it required balancing across the available drivers. When using a resource driver from **outside** of the thread pool, balancing is tricky. The change was original done to avoid having a dedicated driver thread. Now, instead of creating many resource drivers, a single resource driver is used. Each scheduler thread will attempt to "lock" the resource driver before parking on it. If the resource driver is already locked, the thread uses a condition variable to park. Contention should remain low as, under load, the scheduler avoids using the drivers. * Add configuration options to enable I/O / time New configuration options are added to `runtime::Builder` to allow enabling I/O and time drivers on a runtime instance basis. This is useful when wanting to create lightweight runtime instances to execute compute only tasks. * Bug fixes The condition variable parker is updated to the same algorithm used in `std`. This is motivated by some potential deadlock cases discovered by `loom`. The basic scheduler is fixed to fairly schedule tasks. `push_front` was accidentally used instead of `push_back`. I/O, time, and spawning now work from within `spawn_blocking` closures. * Misc cleanup The threaded scheduler is no longer generic over `P :Park`. Instead, it is hard coded to a specific parker. Tests, including loom tests, are updated to use `Runtime` directly. This provides greater coverage. The `blocking` module is moved back into `runtime` as all usage is within `runtime` itself.
2019-11-18chore: refine feature flags (#1785)Carl Lerche
Removes dependencies between Tokio feature flags. For example, `process` should not depend on `sync` simply because it uses the `mpsc` channel. Instead, feature flags represent **public** APIs that become available with the feature enabled. When the feature is not enabled, the functionality is removed. If another Tokio component requires the functionality, it is stays as `pub(crate)`. The threaded scheduler is now exposed under `rt-threaded`. This feature flag only enables the threaded scheduler and does not include I/O, networking, or time. Those features must be explictly enabled. A `full` feature flag is added that enables all features. `stdin`, `stdout`, `stderr` are exposed under `io-std`. Macros are used to scope code by feature flag.
2019-11-16task: move blocking fns into `tokio::task` (#1781)Carl Lerche
2019-11-12reorganize modules (#1766)Carl Lerche
This patch started as an effort to make `time::Timer` private. However, in an effort to get the build compiling again, more and more changes were made. This probably should have been broken up, but here we are. I will attempt to summarize the changes here. * Feature flags are reorganized to make clearer. `net-driver` becomes `io-driver`. `rt-current-thread` becomes `rt-core`. * The `Runtime` can be created without any executor. This replaces `enter`. It also allows creating I/O / time drivers that are standalone. * `tokio::timer` is renamed to `tokio::time`. This brings it in line with `std`. * `tokio::timer::Timer` is renamed to `Driver` and made private. * The `clock` module is removed. Instead, an `Instant` type is provided. This type defaults to calling `std::time::Instant`. A `test-util` feature flag can be used to enable hooking into time. * The `blocking` module is moved to the top level and is cleaned up. * The `task` module is moved to the top level. * The thread-pool's in-place blocking implementation is cleaned up. * `runtime::Spawner` is renamed to `runtime::Handle` and can be used to "enter" a runtime context.