| Date | Wed, 16 Apr 2014 14:45:06 +0100 | From | Will Deacon <> | Subject | Re: [PATCH v7 4/7] arm64: Add ftrace support |
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On Sat, Mar 15, 2014 at 05:45:50AM +0000, AKASHI Takahiro wrote: > This patch implements arm64 specific part to support function tracers, > such as function (CONFIG_FUNCTION_TRACER), function_graph > (CONFIG_FUNCTION_GRAPH_TRACER) and function profiler > (CONFIG_FUNCTION_PROFILER). > > With 'function' tracer, all the functions in the kernel are traced with > timestamps in ${sysfs}/tracing/trace. If function_graph tracer is > specified, call graph is generated. > > The kernel must be compiled with -pg option so that _mcount() is inserted > at the beginning of functions. This function is called on every function's > entry as long as tracing is enabled. > In addition, function_graph tracer also needs to be able to probe function's > exit. ftrace_graph_caller() & return_to_handler do this by faking link > register's value to intercept function's return path. > > More details on architecture specific requirements are described in > Documentation/trace/ftrace-design.txt. > > Reviewed-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com> > Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
I'm still slightly suspicious about the alignment of your ASCII art, but:
Acked-by: Will Deacon <will.deacon@arm.com>
Will
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