On Tue, 2013-04-23 at 18:12 +0000, Christoph Lameter wrote: > On Mon, 22 Apr 2013, Frederic Weisbecker wrote: > > > It's not obvious to find out why the full dynticks subsystem > > doesn't always stop the tick: whether this is due to kthreads, > > posix timers, perf events, etc... > > > > These new tracepoints are here to help the user diagnose > > the failures and test this feature. > > Very good. This will help a lot.
You can also do: cd /sys/kernel/debug/tracing echo 1 > max_graph_depth echo function_graph > current_tracer And then run your code, and look to see what happens on the cpu in question: cat per_cpu/cpuX/trace The "max_graph_depth" of one will make the function graph tracer just trace the first function that enters the kernel. You'll be able to see if the kernel did anything to your userspace application that wasn't planned. "max_graph_depth" was added in 3.9-rc1 -- Steve -- 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/
