On Wed, 2009-02-04 at 16:26 +0100, Frédéric Weisbecker wrote: > 2009/2/4 Anton Vorontsov <avorontsov@xxxxxxxxxxxxx>: > > Irqsoff, switch and preempt tracers use CALLER_ADDR macros, so they > > should select FRAME_POINTER. Otherwise traces are meaningless. > > > > Signed-off-by: Anton Vorontsov <avorontsov@xxxxxxxxxxxxx> > > --- > > kernel/trace/Kconfig | 3 +++ > > 1 files changed, 3 insertions(+), 0 deletions(-) > > > > diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig > > index e2a4ff6..48f7a37 100644 > > --- a/kernel/trace/Kconfig > > +++ b/kernel/trace/Kconfig > > @@ -86,6 +86,7 @@ config IRQSOFF_TRACER > > select TRACE_IRQFLAGS > > select TRACING > > select TRACER_MAX_TRACE > > + select FRAME_POINTER > > help > > This option measures the time spent in irqs-off critical > > sections, with microsecond accuracy. > > @@ -108,6 +109,7 @@ config PREEMPT_TRACER > > depends on DEBUG_KERNEL > > select TRACING > > select TRACER_MAX_TRACE > > + select FRAME_POINTER > > help > > This option measures the time spent in preemption off critical > > sections, with microsecond accuracy. > > @@ -136,6 +138,7 @@ config SCHED_TRACER > > select TRACING > > select CONTEXT_SWITCH_TRACER > > select TRACER_MAX_TRACE > > + select FRAME_POINTER > > help > > This tracer tracks the latency of the highest priority task > > to be scheduled in, starting from the point it has woken up. > > -- > > > Looks right. > > BTW, how behaves builtin_return_address in case of !FRAME_POINTERS ? > I guess it would only work with the first caller builtin_return_address(0) >From ftrace.h: #ifdef CONFIG_FRAME_POINTER /* TODO: need to fix this for ARM */ # define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0)) # define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1)) # define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2)) # define CALLER_ADDR3 ((unsigned long)__builtin_return_address(3)) # define CALLER_ADDR4 ((unsigned long)__builtin_return_address(4)) # define CALLER_ADDR5 ((unsigned long)__builtin_return_address(5)) # define CALLER_ADDR6 ((unsigned long)__builtin_return_address(6)) #else # define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0)) # define CALLER_ADDR1 0UL # define CALLER_ADDR2 0UL # define CALLER_ADDR3 0UL # define CALLER_ADDR4 0UL # define CALLER_ADDR5 0UL # define CALLER_ADDR6 0UL #endif Yep! -- Steve -- 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
