On Mon, 2007-06-04 at 21:00 +0200, Thomas Gleixner wrote:

quoted

Yes, the following patch makes iperf work better than ever.
But are other broken applications going to have same problem.
Sounds like the old "who runs first" fork() problems.

Not really. The fork() "who runs first" problem is nowhere specified.

usleep(0) is well defined:

.... If the value of useconds is 0, then the call has no effect.

So the call into the kernel has been wrong for quite a time.

Just for clarification: I'm not saying that we should break the (broken)
user space ABI. I'm going to work out a patch which prints out a warning
(limited number per boot) and emulating the old behavior by a call to
yield() along with an entry into (mis)feature-removal.txt.

	tglx