預叉，工人和事件MPM之間有什麼區別？

Apache HTTP Server的MPM選擇取決於性能需求與模塊兼容性。 1. Prefork以多進程方式運行，穩定性高但內存消耗大，適合使用mod_php等非線程安全模塊的場景；2. Worker採用多線程混合模型，內存效率更高，適合模塊均為線程安全且需並發處理的環境；3. Event在Worker基礎上優化了連接管理，尤其適合高流量及支持異步操作的現代架構。根據實際應用選擇最合適的MPM可平衡資源佔用與服務穩定性。

Apache HTTP Server uses Multi-Processing Modules (MPMs) to handle requests. The main difference between Prefork, Worker, and Event MPMs lies in how they manage processes and threads — which directly affects performance, resource usage, and compatibility with certain modules like mod_php.

Prefork MPM: Process-Based Handling

The Prefork MPM is the oldest and most stable of the three. It works by creating multiple child processes, each handling one connection at a time. There's no threading involved — just separate processes.

• Each process is independent and doesn't share memory with others.
• It's safe for unstable modules since a crash in one process won't affect others.
• However, it uses more memory because each process has its own copy of everything.

This makes Prefork best suited for environments where stability is key and module compatibility matters — especially when using non-thread-safe modules like mod_php.

Use case:
If you're running older PHP scripts or other non-thread-safe modules, Prefork is your safest bet.

Worker MPM: Threaded and Efficient

Worker MPM uses a hybrid approach — a smaller number of processes, each managing many threads. Each thread can handle a request, so it's much more memory-efficient than Prefork.

• Threads within the same process share memory, reducing overhead.
• More scalable under high traffic.
• But it's less stable if any module isn't thread-safe — a crash in one thread might affect the whole process.

Worker is a good middle ground when you want efficiency but still need some flexibility with modules — assuming they're all thread-safe.

Key points:

• Lower memory usage
• Better concurrency
• Requires careful module selection

Event MPM: Designed for Scalability

Event MPM is an improvement over Worker. It keeps the process/thread model but adds better handling of idle connections — particularly useful with keep-alive requests.

• It separates listening, request processing, and content delivery into different roles.
• Keeps fewer threads busy by offloading waiting tasks (like slow clients).
• Great for high-traffic sites that want to minimize resource use.

However, Event MPM requires modules and backends to be fully async-friendly. If you're using something like PHP via mod_php, this might not work well unless you're on a recent PHP version that supports threading.

Ideal for:

• High-traffic websites
• Sites using reverse proxies or async backends
• Modern setups with thread-safe modules

Choosing the Right One Isn't Hard, Just Context-Dependent

It really comes down to what you're running and how much traffic you expect.

• Go with Prefork if you're using older, non-thread-safe modules.
• Choose Worker if you want better performance and know your modules are thread-safe.
• Use Event if you're optimizing for high concurrency and have a modern stack.

Most Linux distributions default to Event these days, but it's always worth checking based on your actual workload.

基本上就這些。

以上是預叉，工人和事件MPM之間有什麼區別？的詳細內容。更多資訊請關注PHP中文網其他相關文章！