Hi Steven,
Just looking at code of the preemptirqsoff tracer, I wonder if it is
really working as expected.
With the tracer enabled, start_critical_timing will be called only if
_both_ preemption and IRQs are turned off. Instead shouldn't this be
an OR condition (either preemption or IRQs are turned off)?
>From the example in ftrace.txt documentation:
local_irq_disable();
call_function_with_irqs_off();
preempt_disable();
call_function_with_irqs_and_preemption_off();
local_irq_enable();
call_function_with_preemption_off();
preempt_enable();
Looks to me like the preemptirqsoff tracer will starting tracing from
preempt_disable and end at the preempt_enable. Instead, shouldn't we
be tracing starting from the local_irq_disable and end at the
preempt_enable?
Regards,
Joel
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