Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH v3 4/4] nmi_backtrace: generate one-line reports for idle cpus | Date | Tue, 22 Mar 2016 23:28:03 +0100 |
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On Tuesday, March 22, 2016 06:30:05 PM Peter Zijlstra wrote: > On Tue, Mar 22, 2016 at 01:19:39PM -0400, Chris Metcalf wrote: > > When doing an nmi backtrace of many cores, most of which are idle, > > the output is a little overwhelming and very uninformative. Suppress > > messages for cpus that are idling when they are interrupted and just > > emit one line, "NMI backtrace for N skipped: idling at pc 0xNNN". > > > > We do this by grouping all the cpuidle code together into a new > > .cpuidle.text section, and then checking the address of the > > interrupted PC to see if it lies within that section. > > > > This commit suitably tags x86, arm64, and tile idle routines, > > and only adds in the minimal framework for other architectures. > > > > Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> > > Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org> > > Signed-off-by: Chris Metcalf <cmetcalf@mellanox.com> > > For some reason I found a few CPUs using poll_idle(). > > Rafael, when and why would that ever get selected as a useful idle > state? When the predicted idle time is so short even C1 isn't worth it?
Yes, that's the case.
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