多线程中的静态方法

Question

I have a static method

public static void abc(String str) {
    // some code
    str = str + "s";
    // some code
}

Lets assume that this method is called by 100 threads at the same time.

I think that CPU schedules all these threads to execute this static method.

Lets scale up execute requests. Now, there are around 100000 threads calling this static method around same time.

If it is so, this will be a performance overhead (compared to the case where this method is a member of a class). Am I correct?

Answer 1

• In theory, a static call can be made slightly more efficient because it doesn't need to do a virtual function lookup, and it can also avoid the overhead of the hidden "this" parameter.
• In practice, many compilers will optimize this out anyway.
• The cost of context switching the threads will far exceed any difference due to static vs non-static method calling

Answer 2

From the perspective of the OS's scheduler it doesn't matter whether the method is static or not. At machine level both are just subroutines with some parameters. So unless neither methods are synchronized, there shouldn't be any difference.