Negative scalability by removal of lock_kernel()?(Was:Strange performance behavior of 2.4.0-test9)

No.

Please use unserialized accept() _always_, because we can fix that.

Even 2.2.x can be fixed to do the wake-one for accept(), if required. It's not going to be any worse than the current apache config, and basically the less games apache plays, the better the kernel can try to accomodate what apache _really_ wants done. When playing games, you hide what you really want done, and suddenly kernel profiles etc end up being completely useless, because they no longer give the data we needed to fix the problem.

Basically, the whole serialization crap is all about the Apache people saying the equivalent of "the OS does a bad job on something we consider to be incredibly important, so we do something else instead to hide it".

And regardless of _what_ workaround Apache does, whether it is the sucky fcntl() thing or using SysV semaphores, it's going to hide the real issue and mean that it never gets fixed properly.

And in the end it will result in really really bad performance.

Instead, if apache had just done the thing it wanted to do in the first place, the wake-one accept() semantics would have happened a hell of a lot earlier.

Now it's there in 2.4.x. Please use it. PLEASE PLEASE PLEASE don't play games trying to outsmart the OS, it will just hurt Apache in the long run.