title: Who calls delay_tsc() on Linux
body: <p>I used OProfile to profiling my Linux box. During the profiling processes, I've found that besides "<code>native_safe_halt</code>" function, the "<a href="http://lxr.free-electrons.com/source/arch/x86/lib/delay.c#L51" rel="nofollow"><code>delay_tsc</code></a>" is the second most significant function consuming cpu cycles (around 10%). It seems <code>delay_tsc()</code> is a busy loop. But who calls it and what is its function?</p>