http://bugs.winehq.org/show_bug.cgi?id=24558
--- Comment #13 from Eric 8jmtfa1e@gmail.com 2010-11-09 03:41:43 CST --- RtlEnterCriticalSection is followed by NtDelayExecution which is also quite time consuming.
NtDelayExecution can be found at "dlls/ntdll/sync.c".