On Tue, 13 Nov 2007 11:22:45 -0800 David Brownell <[EMAIL PROTECTED]> wrote:
> On Tuesday 13 November 2007, Ingo Molnar wrote: > > > > * David Brownell <[EMAIL PROTECTED]> wrote: > > > > > > > I speculate that either the design has changed (without fanfare), > > > > > or else that stuff is in RT kernels and has not yet gone upstream. > > > > > > > > Well whatever. We shouldn't have to resort to caller-side party > > > > tricks like this to get acceptable performance. > > > > > > I'd be happy if, as originally presented, it were possible to just > > > pass a raw_spinlock_t to spin_lock_irqsave() and friends. > > > > that's a spinlock type abstraction of PREEMPT_RT, not of mainline. > > Any reason that stuff shouldn't move into mainline? > > > > Why do you want to use raw_spinlock_t? > > Already answered elsewhere in this thread ... Can't say I really understood the answer. I don't think we actually know where all of this extra time is being spent? > I'll highlight the > point that such bitops shouldn't be preemption points. Disagree. *everything* should be a preemption point. For internal-implementation details we do need to disable preemtion sometimes (to prevent deadlocks and to protect per-cpu resources). But those preemption-off periods should be minimised. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/