When the custom logic of the IO-based sleep strategies returns
false we already have set the sleeper state to Sleeping and must
reset it.

With Linux 5.18 io_uring supports sending notifications between io_urings.
This removes the need of writing to a specific eventfd to notify
specific sleeping workers.
This greatly reduces the complexity of the sued algorithm because
we do not longer need to prepare two sleeps in an atomic way.

The notify specific algorithm no can be similar to the one used by the
semaphore implementation.
The notifier sets the state of the specific worker to Notified and
if its was previously sleeping it is responsible to send a wakeup
message.

When a worker is going to sleep it sets its state to Running if
it was notified the state is reset and the sleep attempt skipped.
Otherwise a global read is prepared if needed and the worker waits
on its io_uring.

Eventfds are pollable (no iow thread is blocked reading from the IO object)
contrary to waitfds.
And using pipes seams also rather excessive especially since we ensure
that only a single notification is written before it is consumed.

This makes the code of the IO-based sleep strategies easier and I would
expect also faster.

Introduce AbstractIoSleepStrategy holding most of the code needed for
a sleep strategy using an IO object fur suspension/notification.

This changes are used in future patches to implement more IO-based
sleep strategies.

[gitlab-ci] Bump debian-testing-dev image to 1.24

See merge request i4/manycore/emper!410

use liburing 2.2 wrap file provided via meson wrapdb

See merge request i4/manycore/emper!405

fix Future cancellation when using SINGLE_URING

See merge request i4/manycore/emper!407

When using the SINGLE_URING configuration the Future semaphore is used
to ensure that a forgotten Future is dropped after it is prepared and
not needed anymore.

Using the future after signaling its semaphore and thus allowing its
concurrent destruction is obviously broken.

Signal the semaphore after all preparation work is done.

Fixes: 9c0f2143

Fixes: 3fb3892b

[Semaphore] make default constructor more explicit

See merge request i4/manycore/emper!408

The CancelFutureTest fails for libc++ because it uses two
emper::Semaphores to coordinate the involved fibers.

Using gcc and stdlibc++ the default constructor initialized the
semaphore count to 0.

The default constructor using clang and libc++ does not initialize the
semaphore count member and thus causing the CancelFutureTest to misbehave.

Add the Big Fancy Pulser 9000 (BFP 9K) evaluation

See merge request !397

[README] Fibirl uses spawn/sync as keywords (and no longer fork/join)

See merge request i4/manycore/emper!403

[io/Stats] For AlarmFutures (TIMEOUT) expect them to return ETIME

See merge request i4/manycore/emper!402

[Makefile] Add asan(-test) targets

See merge request i4/manycore/emper!398

LTO

See merge request i4/manycore/emper!401

This prevents a linker error because of undefined symbols when LTO is
used.

[Runtime] Switch logging of env var handling from DBG() to LOGI()

See merge request i4/manycore/emper!400

Also use std::boolalpha to print ture/false.

[SpuriousFutex2Semaphore] Add missing emper-config.h include

See merge request i4/manycore/emper!399

Fixes: f4e72a97 ("[iwyu] Fix includes as per iwyu 0.18")

[ContextManager] Remove the put/get free context cycle

See merge request i4/manycore/emper!396

The put/get free context cycle in ContextManager::start() (if
continuation stealing is enabled) became unnecessary with
c66551bf ("[Context] Use 'jmp' instead of 'ret' to kickoff the
context").

Fix ContextManager with MemoryManager

See merge request i4/manycore/emper!395