What does php lack compared to C/C++ or Java? Multithreading, multithreading, multithreading…

I was chatting with a former colleague yesterday and complained about PHP and Swoole. He believed that PHP was full of pitfalls and that PHP had great limitations. PHP+Swoole is not suitable for high-concurrency servers, C+Swoole is the best solution. C++ has various data structures, C++ can open threads, and C++ can share objects. It seems necessary to explain it carefully.

What does HP lack compared to C/C++ or Java? Multi-threading, multi-threading, multi-threading...

Yes. PHP has fewer threads than C/C++ and Java. PHP only has a multi-process solution, so global variables and objects in PHP are not shared, data structures cannot be operated across processes, Socket file descriptors cannot be shared, etc. So PHP has limitations?

Multi-threading seems to be much more powerful than multi-processing. In fact, I can responsibly tell you that multi-threading brings more pitfalls.

Data synchronization issues will crash you. Either sacrifice performance and add locks everywhere, or use hell-hard lock-free concurrent programming. As far as I know, there are very few people in China who can master this skill.

Don’t think that everything will be fine if you add a lock. You will be in trouble with the deadlock problem. When your program logic becomes complex, locks become increasingly difficult to control. Once deadlocked, your program is basically doomed.

If a thread hangs, all threads will exit

Instead, we are looking at multiple processes, which is actually much simpler.

With inter-process communication, you can basically achieve any data sharing. For example, a process is used to specifically store data structures and objects, and all data operations of other processes are delivered to this process

Multiple processes do not require locks

Multiple processes can use shared memory data structures to implement some multi-threading functions. For example, Table and Atomic provided by Swoole can realize data sharing, but the cost is very low. Shared memory queues will be added in the future

The so-called PHP restricts Swoole is completely nonsense. Proper use of Table, Atomic, SendMessage/PipeMessage, and Task provided by Swoole can completely implement asynchronous and non-blocking code logic.

Do programs written in C++ have better performance?

This is completely blind superstition. C++ does have advantages for computationally intensive programs. The core of the concurrent server is IO, not large-scale intensive computing. C++ has no advantages from a language perspective. In addition, most data structures in C++ have corresponding implementations in PHP. If it is not possible, you can still solve it by writing a special extension yourself.

The high-concurrency server can maintain 10W connections per machine and can handle 3-5W messages sent and received per second. This level of performance can already be applied to BAT's core system.

What does it mean to have fast development efficiency?

This colleague also said that although PHP server development is faster than C++, C++ is still needed to pursue the ultimate performance. I'm going to tell you what it means to be efficient. Developing a good program is not an easy task and requires programmers to invest a lot of time and energy. The significance of improving development efficiency is not simply that I can complete the work in less time, but that in the remaining time you can add unit tests, fix bugs, improve user experience, improve details, provide supporting tools, optimize performance, add key logs, and increase Monitor alarms and add disaster recovery plans.