Re: [PATCH 1/2] tracing/function-graph-tracer: signal interrupts entry/exit points on outpout

[Ingo Molnar <mingo@elte.hu>]

* Frederic Weisbecker <fweisbec@gmail.com> wrote:

> +/* Used during output to find the interrupts entry/exit points */
> +const char *ftrace_graph_irq_entries[] = {
> +	"smp_call_function_single_interrupt",
> +	"xen_call_function_single_interrupt",
> +	"wrapper_smp_local_timer_interrupt",
> +	"smp_irq_move_cleanup_interrupt",
> +	"smp_call_function_interrupt",
> +	"xen_call_function_interrupt",
> +	"smp_apic_timer_interrupt",
> +	"uv_bau_message_interrupt",
> +	"mce_threshold_interrupt",
> +	"smp_spurious_interrupt",
> +	"smp_thermal_interrupt",
> +	"smp_error_interrupt",
> +	"do_IRQ",
> +	NULL

hm, couldnt we move these symbols to a separate section, and then only 
check for [section.start ... section.end] instead of this ugly and slow 
array?

Missing a few annotations initially is no big deal - we wont have 
pretty-print. do_IRQ() and smp_apic_timer_interrupt is what matters most 
in practice. "__irqentry" section annotation or so, which puts them into 
.text.irqentry or so - and then irqentry_start/end are extracted via 
appropriate glue in the arch/x86/kernel/vmlinux* linker script.

	Ingo