On Thu, 17 Mar 2016 12:16:11 +0100 (CET) Thomas Gleixner <t...@linutronix.de> wrote:
> On Thu, 17 Mar 2016, Peter Zijlstra wrote: > > Also, maybe the tracer should measure the time from need_resched() > > getting true until the next preemption point, instead of the entire time > > preemption was disabled. Which would avoid the entire issue altogether. > > Well, that only gives you the information on a actual preemption, but not > information about long preempt disabled regions which can cause a problem > eventually. > Actually, I was thinking the reverse. If need_resched() is called and is false, then do a reset of the preemption time. But if need_resched() is true, then do nothing, as that would measure the total time preempt disable was set and a task could not schedule. Question is, should this be a hook and each location audited, or add this to need_resched() itself? -- Steve
