* Added `Ractor::Port`
* `Ractor::Port#receive` (support multi-threads)
* `Rcator::Port#close`
* `Ractor::Port#closed?`
* Added some methods
* `Ractor#join`
* `Ractor#value`
* `Ractor#monitor`
* `Ractor#unmonitor`
* Removed some methods
* `Ractor#take`
* `Ractor.yield`
* Change the spec
* `Racotr.select`
You can wait for multiple sequences of messages with `Ractor::Port`.
```ruby
ports = 3.times.map{ Ractor::Port.new }
ports.map.with_index do |port, ri|
Ractor.new port,ri do |port, ri|
3.times{|i| port << "r#{ri}-#{i}"}
end
end
p ports.each{|port| pp 3.times.map{port.receive}}
```
In this example, we use 3 ports, and 3 Ractors send messages to them respectively.
We can receive a series of messages from each port.
You can use `Ractor#value` to get the last value of a Ractor's block:
```ruby
result = Ractor.new do
heavy_task()
end.value
```
You can wait for the termination of a Ractor with `Ractor#join` like this:
```ruby
Ractor.new do
some_task()
end.join
```
`#value` and `#join` are similar to `Thread#value` and `Thread#join`.
To implement `#join`, `Ractor#monitor` (and `Ractor#unmonitor`) is introduced.
This commit changes `Ractor.select()` method.
It now only accepts ports or Ractors, and returns when a port receives a message or a Ractor terminates.
We removes `Ractor.yield` and `Ractor#take` because:
* `Ractor::Port` supports most of similar use cases in a simpler manner.
* Removing them significantly simplifies the code.
We also change the internal thread scheduler code (thread_pthread.c):
* During barrier synchronization, we keep the `ractor_sched` lock to avoid deadlocks.
This lock is released by `rb_ractor_sched_barrier_end()`
which is called at the end of operations that require the barrier.
* fix potential deadlock issues by checking interrupts just before setting UBF.
https://bugs.ruby-lang.org/issues/21262
`USE_RUBY_DEBUG_LOG` was only defined when `RUBY_DEVEL` is defined.
This patch removes this dependency (`USE_RUBY_DEBUG_LOG` is defined
independently from `RUBY_DEVEL`).
Do not commit a patch which enables `USE_RUBY_DEBUG_LOG`.
Write barrier requires VM lock because it accesses VM global bitmap
but RB_VM_LOCK_ENTER() can invoke GC because another ractor can wait
to invoke GC and RB_VM_LOCK_ENTER() is barrier point. This means that
before protecting by a write barrier, GC can invoke.
To prevent such situation, RB_VM_LOCK_ENTER_NO_BARRIER() is introduced.
This lock primitive does not become GC barrier points.
On windows, MJIT doesn't work without this patch because of
the declaration of ruby_single_main_ractor. This patch fix this
issue and move the definition of it from ractor.c to vm.c to locate
near place of ruby_current_vm_ptr.
ruby_multi_ractor was a flag that indicates the interpreter doesn't
make any additional ractors (single ractor mode).
Instead of boolean flag, ruby_single_main_ractor pointer is introduced
which keeps main ractor's pointer if single ractor mode. If additional
ractors are created, ruby_single_main_ractor becomes NULL.
rb_ractor_main_p() need to access to the ractor pointer in TLS.
However it is slow operation so that we need to skip this check
if it is not multi-ractor mode (!ruby_multi_ractor).
This performance regression is pointed at
https://bugs.ruby-lang.org/issues/17100#note-27
This commit introduces Ractor mechanism to run Ruby program in
parallel. See doc/ractor.md for more details about Ractor.
See ticket [Feature #17100] to see the implementation details
and discussions.
[Feature #17100]
This commit does not complete the implementation. You can find
many bugs on using Ractor. Also the specification will be changed
so that this feature is experimental. You will see a warning when
you make the first Ractor with `Ractor.new`.
I hope this feature can help programmers from thread-safety issues.
