Currently, runner local queues rely on a RwLock<Vec<Arc<ConcurrentQueue>>>> to store the queues instead of using actual thread-local storage.
This adds thread_local as a dependency, but this should allow the executor to work steal without needing to hold a lock, as well as allow tasks to schedule onto the local queue directly, where possible, instead of always relying on the global injector queue.
Fixes#62
Co-authored-by: John Nunley <jtnunley01@gmail.com>
The atomic orderings on State::notified might be too strong, as it's primarily
being used as a deterrent against waking up too many threads. This PR weakens
their sequentially consistent operations to Acquire/Release.
Whoops, I accidentally reinvented a semaphore and made the example a lot
more complicated than it needed to be.
Signed-off-by: John Nunley <dev@notgull.net>
After smol-rs/async-task#37 I meant to add this to the executor. This
commit makes it so all panics are surfaced in the tasks that the user
calls. Hopefully this improves ergonomics.
Signed-off-by: John Nunley <dev@notgull.net>
Signed-off-by: Alain Zscheile <fogti+devel@ytrizja.de>
`futures-lite` in the dev dependencies added a `block_on` call that was
not present in the WASM build, causing a compile error. This PR makes
sure that the `std` feature of `futures-lite` is enabled in Cargo.toml.
This also adds a CI check to ensure that this doesn't happen again
Signed-off-by: John Nunley <dev@notgull.net>
In many issues I've mentioned that the executors in this crate are just
reference executors. However, this is not documented in the crate
itself.
This commit adds a disclaimer to the crate documentation and to
README.md that these are reference executors that shouldn't be relied on
for performance.
Signed-off-by: John Nunley <dev@notgull.net>
This was added in #37 as an optimization, but has since lead to many bugs. See
the issues #53, #57 and #60 for more information. I do not have the bandwidth
to address all of these bugs, so I'm taking the path of least resistance by
just removing the problematic code.
CLoses#53, #57 and #60
Signed-off-by: John Nunley <dev@notgull.net>
* Fix a bug where TLS would become None
The bug is invoked as follows:
- Runner 1 is created and stores the current version of the TLS
LOCAL_QUEUE variable, which is None.
- Runner 2 is also created. It stores the current version of the TLS
variable as well, which is Runner 1's queue.
- Runner 1 is dropped. It stores None into the LOCAL_QUEUE variable.
- Runner 2 tries to run. It reads from the LOCAL_QUEUE variable, sees
that it is None, and panics.
This could be solved by just not using the local queue if the variable
is None. However, we can do one better; if the slot is open, we can
optimize the runner by replacing it with our own queue. This should
allow for the local queue to be used more often.
Closes#54
Signed-off-by: John Nunley <dev@notgull.net>
This commit makes sure that the run() and tick() functions produce
futures that are Send and Sync, to prevent a regression introduced in
PR #37. Tests are also added to prevent this regression in the future.
Signed-off-by: John Nunley <dev@notgull.net>
This commit adds an optimization where a thread-local variable contains the queue of the
current runner. Rather than pushing to the global queue and hoping that a local queue
eventually picks it up, tasks are pushed directly to this local queue if available.
This has led to speedups of up to 70% in some cases and up to 10% in other workloads.
John Nunley
James Liu
Jacob Rothstein
dependabot[bot]
Taiki Endo
John Nunley
Yosh