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Update examples in README

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coderstephen 2015-08-24 13:56:30 -05:00
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@ -18,34 +18,58 @@ A few benchmarks are provided for analysis and study. Can be used to back up imp
## Documentation
Concurrent can use either process forking or true threading to parallelize execution. Threading provides better performance and is compatible with Unix and Windows but requires ZTS (Zend thread-safe) PHP, while forking has no external dependencies but is only compatible with Unix systems. If your environment works meets neither of these requirements, this library won't work.
### Contexts
Concurrent provides a generic interface for working with parallel tasks called "contexts". All contexts are capable of being executed in parallel from the main program code. Each context is assigned a closure to execute when it is created, and the returned value is passed back to the parent context. Concurrent goes for a "shared-nothing" architecture, so any variables inside the closure are local to that context and can store any non-safe data.
### Threads
Threading is a cross-platform concurrency method that is fast and memory efficient. Thread contexts take advantage of an operating system's multi-threading capabilities to run code in parallel. A spawned thread will run completely parallel to the parent thread, each with its own environment. Each thread is assigned a closure to execute when it is created, and the returned value is passed back to the parent thread. Concurrent goes for a "shared-nothing" architecture, so any variables inside the closure are local to that thread and can store any non-safe data.
You can wait for a context to close by calling `join()`. Joining does not block the parent context and will asynchronously wait for the child context to finish before resolving.
You can spawn a new thread with the `Thread::spawn()` method:
```php
use Icicle\Concurrent\Threading\ThreadContext;
use Icicle\Concurrent\Threading\Thread;
use Icicle\Coroutine;
use Icicle\Loop;
Coroutine\create(function () {
$thread = new ThreadContext(function () {
$thread = Thread::spawn(function () {
print "Hello, World!\n";
});
$thread->start();
yield $thread->join();
});
Loop\run();
```
You can wait for a thread to finish by calling `join()`. Joining does not block the parent thread and will asynchronously wait for the child thread to finish before resolving.
### Forks
For Unix-like systems, you can create parallel execution using fork contexts. Though not as efficient as multi-threading, in some cases forking can take better advantage of some multi-core processors than threads. Fork contexts use the `pcntl_fork()` function to create a copy of the current process and run alternate code inside the new process.
Spawning and controlling forks are quite similar to creating threads. To spawn a new fork, use the `Fork::spawn()` method:
```php
use Icicle\Concurrent\Forking\Fork;
use Icicle\Coroutine;
use Icicle\Loop;
Coroutine\create(function () {
$fork = Fork::spawn(function () {
print "Hello, World!\n";
});
yield $fork->join();
});
Loop\run();
```
Calling `join()` on a fork will asynchronously wait for the forked process to terminate, similar to the `pcntl_wait()` function.
#### Synchronization with channels
Contexts wouldn't be very useful if they couldn't be given any data to work on. The recommended way to share data between contexts is with a `Channel`. A channel is a low-level abstraction over local, non-blocking sockets, which can be used to pass messages and objects between two contexts. Channels are non-blocking and do not require locking. For example:
Threads and forks wouldn't be very useful if they couldn't be given any data to work on. The recommended way to share data between contexts is with a `Channel`. A channel is a low-level abstraction over local, non-blocking sockets, which can be used to pass messages and objects between two contexts. Channels are non-blocking and do not require locking. For example:
```php
use Icicle\Concurrent\Sync\Channel;
use Icicle\Concurrent\Threading\ThreadContext;
use Icicle\Concurrent\Threading\Thread;
use Icicle\Coroutine;
use Icicle\Loop;
@ -53,12 +77,11 @@ Coroutine\create(function () {
list($socketA, $socketB) = Channel::createSocketPair();
$channel = new Channel($socketA);
$thread = new ThreadContext(function ($socketB) {
$thread = Thread::spawn(function ($socketB) {
$channel = new Channel($socketB);
yield $channel->send("Hello!");
}, $socketB);
$thread->start();
$message = (yield $channel->receive());
yield $thread->join();
});
@ -69,11 +92,5 @@ Loop\run();
### Synchronization with parcels
Parcels are shared containers that allow you to store context-safe data inside a shared location so that it can be accessed by multiple contexts. To prevent race conditions, you still need to access a parcel's data exclusively, but Concurrent allows you to acquire a lock on a parcel asynchronously without blocking the context execution, unlike traditional mutexes.
### Threading
Threading is a cross-platform concurrency method that is fast and memory efficient. Thread contexts take advantage of an operating system's multi-threading capabilities to run code in parallel.
### Forking
For Unix-like systems, you can create parallel execution using fork contexts. Though not as efficient as multi-threading, in some cases forking can take better advantage of some multi-core processors than threads. Fork contexts use the `pcntl_fork()` function to create a copy of the current process and run alternate code inside the new process.
## License
All documentation and source code is licensed under the Apache License, Version 2.0 (Apache-2.0). See the [LICENSE](LICENSE) file for details.