On Thu, 7 Nov 2013, Frederic Weisbecker wrote: > On Thu, Nov 07, 2013 at 12:21:11PM +0100, Thomas Gleixner wrote: > > Though it's not a full solution. It needs some thought versus the > > softirq code of timers. Assume we have only one timer queued 1000 > > ticks into the future. So this change will cause the timer softirq not > > to be called until that timer expires and then the timer softirq is > > going to do 1000 loops until it catches up with jiffies. That's > > anything but pretty ... > > I see, so the problem is that we raise the timer softirq unconditionally > from the tick? Right. > Ok we definetly don't want to keep that behaviour, even if softirqs are not > threaded, that's an overhead. So I'm looking at that loop in __run_timers() > and I guess you mean the "base->timer_jiffies" incrementation? > > That's indeed not pretty. How do we handle exit from long dynticks > idle periods? Are we doing that loop until we catch up with the new > jiffies? Right. I realized that right after I hit send :) > Then it relies on the timer cascade stuff which is very obscure code to me... It's not that bad, really. I have an idea how to fix that. Needs some rewriting though. Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
