[gitlab-ci] disable IO since io_uring is not available in our CI

See merge request !74

[clang-tidy] Set HeaderFilterRegex to '.*'

See merge request !73

This matches now all headers in the repository, instead of just the
ones in the emper/ subdirectory, for example the
/tests/fixtures.network.hpp header.

Minor fixes

See merge request !72

Both are semantically equivalent, and it appears that "enum struct" is
a little bit more confusing.

The operation is called 'dequeue', 'deque' is a double-ended queue.

Worker exclusive uring

See merge request !54

The echo client established X connections and start the
echo phase after all sockets are connected.

Each client Fiber measures the time from sending the message until
receiving the echo.

Empers IO design is based on a proactor pattern where each worker
can issue IO requests through its exclusive IoContext object which wraps an
io_uring instance.

IO completions are reaped at 4 places:
1. After a submit to collect inline completions
2. Before dispatching a new Fiber
3. When no new IO can be submitted because the completion queue is full
4. And by a global completer thread which gets notified about completions
   on worker IoContexts through registered eventfds

All IO requests are modeled as Future objects which can be either
instantiated and submitted manually, retrieved by POSIX-like non-blocking
or implicitly used by posix-like blocking functions.

User facing API is exported in the following headers:
* emper/io.hpp (POSIX-like)
* emper.h (POSIX-like)
* emper/io/Future.hpp

Catching short write/reads/sends and resubmitting the request without
unblocking the Fiber is supported.

Using AlarmFuture objects Fibers have a emper-native way to sleep for
a given time.

IO request timeouts with TimeoutWrapper class.
Request Cancellation is supported with Future::cancel() or the
CancelWrapper() Future class.

A proactor design demands that buffers are committed to the kernel
as long as the request is active. To guaranty memory safety Futures
get canceled in their Destructor which will only return after the committed
memory is free to use.

Linking Futures to chains is supported using the Future::SetDependency()
method. Future are submitted when their last Future gets submitted.
A linked Request will start if the previous has finished.
Error or partial completions will cancel the not started tail of a chain.

TODO: Handle possible situations where the CQ of the global completer is full
and no more sqe can be submitted to the SQ.

This feature must be activated using the blocked_context_set meson option.

De-duplicate work-stealing scheduling code

See merge request !69

[tools] Add script to fix the includes with IWYU

Closes #8

See merge request !70

This introduces AbstractWorkStealingScheduler which holds the common
work-stealing scheduling strategy.

Fixes #8.

[test] Add EMPER test runner

See merge request i4/manycore/emper!48

Add option to include timestamp in EMPER log messages

See merge request i4/manycore/emper!68

This also changes emper_log so that a std::ostringstream is used to
assemble the log message.

[tests] Include fiberNum in SimpleActorTest WDBG() log

See merge request !67

[LAWS] Attempt to steal from all other workers instead of just one

Closes #6

See merge request !66

The LAWS strategy, unlike the WS strategy, previously only attempted
to steal from one victim, instead of trying all other workers. This
probably caused SimpleActorTest to sporadically timeout, as all
workers went to sleep.

With this change, LAWS attempts, just like WS, to steal from all other
workers. In a next step, we may want to reduce the duplicated code
resulting from this.

Fixes #6.

[Runtime] Add missing constexpr

See merge request !65

Suggested-by: Florian Fischer <florian.fl.fischer@fau.de>

Worker wakeup strategy enum

See merge request i4/manycore/emper!62

Initiailze the WORKER_WAKEUP_STRATEGY via the contents of the
EMPER_WORKER_WAKEUP_STRATEGY macro. This makes it easier to add
additional strategies later on.

emper/emper/Worker.hpp:10:7: error: Excessive padding in 'class Worker' (123 padding bytes, where 59 is optimal).
Optimal fields order:
seed,
workerId,
consider reordering the fields or adding explicit padding members [clang-analyzer-optin.performance.Padding,-warnings-as-errors]

[tests] Increase test timeout from 60 seconds to 180 seconds

See merge request !64

We see SimpleActorTest timing out a lot in our CI when LAWS is used,
and from the logs it appears likely that this is a valid
timeout (versus the test just being stuck). Let us increase the test
timeout and see if it helps. Or if it is a "real" timeout.

[tests] Increase test timeout from 60 seconds to 180 seconds

See merge request !63

We see SimpleActorTest timing out a lot in our CI, and from the logs
it appears likely that this is a valid timeout (versus the test just
being stuck). Let us increase the test timeout and see if it helps.

Fix headers when EMPER_LOG_OFF is defined

See merge request !59

make worker wakeup strategy compile time configurable

See merge request !61