On Mon, Feb 28, 2011 at 04:48:43PM +0000, Mindaugas Rasiukevicius wrote: > Why interrupts are disabled here? Calling xc_wait() with interrupts > disabled is, at minimum, very expensive, and I would say it is wrong. > Note that xc_wait(9) does not necessary spin - it can block.
Because interrupts must be disabled when APERF and MPERF are read. See the references in the comment, particularly the AMD one. - Jukka.
