On Mon, 2007-06-04 at 10:51 -0700, Stephen Hemminger wrote:

quoted

I doubt that. This is in the iperf code itself.

void thread_rest ( void ) {
#if defined( HAVE_THREAD )
#if defined( HAVE_POSIX_THREAD )
    // TODO add checks for sched_yield or pthread_yield and call that
    // if available
    usleep( 0 );

----------^^^^

It results in a nanosleep({0,0}, NULL)

	tglx

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.

	tglx