In the multi-threaded scheduler, when there are no tasks on the local
queue, a worker will attempt to pull tasks from the injection queue.
Previously, the worker would only attempt to poll one task from the
injection queue then continue trying to find work from other sources.
This can result in the injection queue backing up when there are many
tasks being scheduled from outside of the runtime.
This patch updates the worker to try to poll more than one task from the
injection queue when it has no more local work. Note that we also don't
want a single worker to poll **all** tasks on the injection queue as
that would result in work becoming unbalanced.
Adds support for instrumenting the poll times of all spawned tasks. Data is tracked in a histogram. The user must specify the histogram scale and bucket ranges. Implementation-wise, the same strategy is used in the runtime where we are just using atomic counters. Because instrumenting each poll duration will result in frequent calls to `Instant::now()`, I think it should be an opt-in metric.
This patch updates CI to use `cross` to run Tokio tests on virtualized
ARM and i686 VMs. Because ipv6 doesn't work on Github action running in
a docker instance, those tests are disabled
Publish the blocking thread pool metrics as thread-safe values, written
under the blocking thread pool's lock and able to be read in a lock-free
fashion by any reader.
Fixes#5156
The signal driver uses a `UnixStream` to receive signal events.
Previously, the signal driver used `PollEvented` internally to receive
events on the `UnixStream`. However, using `PollEvented` from
within a runtime driver created a circular link between the runtime and
the `PollEvented` instance.
This patch replaces `PollEvented` usage in favor of accessing the I/O
driver directly. The I/O driver now reserves a token for signal-related
events and tracks signal readiness internally. The signal driver queries
the I/O driver to check for signal-related readiness.
For historical reasons, the current-thread runtime's scheduler was named
BasicScheduler and the multi-thread runtime's scheduler were named
ThreadPool. This patch renames the schedulers to mirror the runtime
names to increase consistency. This patch also moves the scheduler
implementations into a new `runtime::scheduler` module.
This adds initial, unstable, support for the wasm32-wasi target. Not all of Tokio's
features are supported yet as WASI's non-blocking APIs are still limited.
Refs: tokio-rs/tokio#4827
Alice Ryhl