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Commit 32eb3d0d authored by Steven Rostedt (Red Hat)'s avatar Steven Rostedt (Red Hat) Committed by Steven Rostedt
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tracing/samples: Update the trace-event-sample.h with TRACE_DEFINE_ENUM() 

Document the use of TRACE_DEFINE_ENUM() by adding enums to the
trace-event-sample.h and using this macro to convert them in the format
files.

Also update the comments and sho the use of __print_symbolic() and
__print_flags() as well as adding comments abount __print_array().

Link: http://lkml.kernel.org/r/20150403013802.220157513@goodmis.org



Reviewed-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Tested-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 3673b8e4

samples/trace_events/trace-events-sample.h

+63 −1
Original line number Diff line number Diff line
@@ -198,8 +198,30 @@ static inline int __length_of(const int *list) 
		;

	return i;

}



enum {

	TRACE_SAMPLE_FOO = 2,

	TRACE_SAMPLE_BAR = 4,

	TRACE_SAMPLE_ZOO = 8,

};

#endif



/*

 * If enums are used in the TP_printk(), their names will be shown in

 * format files and not their values. This can cause problems with user

 * space programs that parse the format files to know how to translate

 * the raw binary trace output into human readable text.

 *

 * To help out user space programs, any enum that is used in the TP_printk()

 * should be defined by TRACE_DEFINE_ENUM() macro. All that is needed to

 * be done is to add this macro with the enum within it in the trace

 * header file, and it will be converted in the output.

 */



TRACE_DEFINE_ENUM(TRACE_SAMPLE_FOO);

TRACE_DEFINE_ENUM(TRACE_SAMPLE_BAR);

TRACE_DEFINE_ENUM(TRACE_SAMPLE_ZOO);



TRACE_EVENT(foo_bar,



	TP_PROTO(const char *foo, int bar, const int *lst,
@@ -224,7 +246,47 @@ TRACE_EVENT(foo_bar, 
		__assign_bitmask(cpus, cpumask_bits(mask), num_possible_cpus());

	),



	TP_printk("foo %s %d %s %s (%s)", __entry->foo, __entry->bar,

	TP_printk("foo %s %d %s %s %s %s (%s)", __entry->foo, __entry->bar,



/*

 * Notice here the use of some helper functions. This includes:

 *

 *  __print_symbolic( variable, { value, "string" }, ... ),

 *

 *    The variable is tested against each value of the { } pair. If

 *    the variable matches one of the values, then it will print the

 *    string in that pair. If non are matched, it returns a string

 *    version of the number (if __entry->bar == 7 then "7" is returned).

 */

		  __print_symbolic(__entry->bar,

				   { 0, "zero" },

				   { TRACE_SAMPLE_FOO, "TWO" },

				   { TRACE_SAMPLE_BAR, "FOUR" },

				   { TRACE_SAMPLE_ZOO, "EIGHT" },

				   { 10, "TEN" }

			  ),



/*

 *  __print_flags( variable, "delim", { value, "flag" }, ... ),

 *

 *    This is similar to __print_symbolic, except that it tests the bits

 *    of the value. If ((FLAG & variable) == FLAG) then the string is

 *    printed. If more than one flag matches, then each one that does is

 *    also printed with delim in between them.

 *    If not all bits are accounted for, then the not found bits will be

 *    added in hex format: 0x506 will show BIT2|BIT4|0x500

 */

		  __print_flags(__entry->bar, "|",

				{ 1, "BIT1" },

				{ 2, "BIT2" },

				{ 4, "BIT3" },

				{ 8, "BIT4" }

			  ),

/*

 *  __print_array( array, len, element_size )

 *

 *    This prints out the array that is defined by __array in a nice format.

 */

		  __print_array(__get_dynamic_array(list),

				__get_dynamic_array_len(list),

				sizeof(int)),