最近我听到一些人说,在Linux中,使用进程几乎总是比使用线程更好,因为Linux在处理进程方面非常高效,而且与线程相关的问题太多了(比如锁)。然而,我对此持怀疑态度,因为在某些情况下,线程似乎可以带来相当大的性能提升。

因此,我的问题是,当遇到线程和进程都可以很好地处理的情况时,我应该使用进程还是线程?例如,如果我正在编写一个web服务器,我应该使用进程还是线程(或组合)?


当前回答

Threads -- > Threads shares a memory space,it is an abstraction of the CPU,it is lightweight. Processes --> Processes have their own memory space,it is an abstraction of a computer. To parallelise task you need to abstract a CPU. However the advantages of using a process over a thread is security,stability while a thread uses lesser memory than process and offers lesser latency. An example in terms of web would be chrome and firefox. In case of Chrome each tab is a new process hence memory usage of chrome is higher than firefox ,while the security and stability provided is better than firefox. The security here provided by chrome is better,since each tab is a new process different tab cannot snoop into the memory space of a given process.

其他回答

其他人讨论了这些考虑因素。

也许重要的区别是,在Windows中,与线程相比,进程是沉重和昂贵的,而在Linux中,差异要小得多,所以等式在不同的点上平衡。

我不得不同意你所听到的。当我们对我们的集群(xhpl等)进行基准测试时,我们总是通过进程而不是线程获得明显更好的性能。< /轶事>

更复杂的是,还有线程本地存储和Unix共享内存。

Thread-local storage allows each thread to have a separate instance of global objects. The only time I've used it was when constructing an emulation environment on linux/windows, for application code that ran in an RTOS. In the RTOS each task was a process with it's own address space, in the emulation environment, each task was a thread (with a shared address space). By using TLS for things like singletons, we were able to have a separate instance for each thread, just like under the 'real' RTOS environment.

共享内存(显然)可以为您带来让多个进程访问相同内存的性能优势,但代价是必须正确地同步进程。一种方法是让一个进程在共享内存中创建一个数据结构,然后通过传统的进程间通信(如命名管道)向该结构发送句柄。

如果你需要共享资源,你真的应该使用线程。

还要考虑这样一个事实:线程之间的上下文切换比进程之间的上下文切换代价要小得多。

我认为没有理由明确地使用单独的进程,除非你有一个很好的理由这样做(安全,经过验证的性能测试,等等……)

Threads -- > Threads shares a memory space,it is an abstraction of the CPU,it is lightweight. Processes --> Processes have their own memory space,it is an abstraction of a computer. To parallelise task you need to abstract a CPU. However the advantages of using a process over a thread is security,stability while a thread uses lesser memory than process and offers lesser latency. An example in terms of web would be chrome and firefox. In case of Chrome each tab is a new process hence memory usage of chrome is higher than firefox ,while the security and stability provided is better than firefox. The security here provided by chrome is better,since each tab is a new process different tab cannot snoop into the memory space of a given process.