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Commit a2a16d6a authored by Steven Rostedt's avatar Steven Rostedt
Browse files

function-graph: add option to calculate graph time or not 



graph time is the time that a function is executing another function.
Thus if function A calls B, if graph-time is set, then the time for
A includes B. This is the default behavior. But if graph-time is off,
then the time spent executing B is subtracted from A.

Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
parent cafb168a

include/linux/ftrace.h

+1 −2
Original line number Diff line number Diff line
@@ -365,6 +365,7 @@ struct ftrace_ret_stack { 
	unsigned long ret;

	unsigned long func;

	unsigned long long calltime;

	unsigned long long subtime;

};



/*
@@ -376,8 +377,6 @@ extern void return_to_handler(void); 


extern int

ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth);

extern void

ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret);



/*

 * Sometimes we don't want to trace a function with the function

kernel/trace/ftrace.c

+20 −1
Original line number Diff line number Diff line
@@ -604,6 +604,7 @@ static int profile_graph_entry(struct ftrace_graph_ent *trace) 
static void profile_graph_return(struct ftrace_graph_ret *trace)

{

	struct ftrace_profile_stat *stat;

	unsigned long long calltime;

	struct ftrace_profile *rec;

	unsigned long flags;
@@ -612,9 +613,27 @@ static void profile_graph_return(struct ftrace_graph_ret *trace) 
	if (!stat->hash)

		goto out;



	calltime = trace->rettime - trace->calltime;



	if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {

		int index;



		index = trace->depth;



		/* Append this call time to the parent time to subtract */

		if (index)

			current->ret_stack[index - 1].subtime += calltime;



		if (current->ret_stack[index].subtime < calltime)

			calltime -= current->ret_stack[index].subtime;

		else

			calltime = 0;

	}



	rec = ftrace_find_profiled_func(stat, trace->func);

	if (rec)

		rec->time += trace->rettime - trace->calltime;

		rec->time += calltime;



 out:

	local_irq_restore(flags);

}

kernel/trace/trace.c

+3 −1
Original line number Diff line number Diff line
@@ -255,7 +255,8 @@ static DECLARE_WAIT_QUEUE_HEAD(trace_wait); 


/* trace_flags holds trace_options default values */

unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |

	TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | TRACE_ITER_SLEEP_TIME;

	TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | TRACE_ITER_SLEEP_TIME |

	TRACE_ITER_GRAPH_TIME;



/**

 * trace_wake_up - wake up tasks waiting for trace input
@@ -317,6 +318,7 @@ static const char *trace_options[] = { 
	"latency-format",

	"global-clock",

	"sleep-time",

	"graph-time",

	NULL

};

kernel/trace/trace.h

+1 −0
Original line number Diff line number Diff line
@@ -685,6 +685,7 @@ enum trace_iterator_flags { 
	TRACE_ITER_LATENCY_FMT		= 0x40000,

	TRACE_ITER_GLOBAL_CLK		= 0x80000,

	TRACE_ITER_SLEEP_TIME		= 0x100000,

	TRACE_ITER_GRAPH_TIME		= 0x200000,

};



/*

kernel/trace/trace_functions_graph.c

+4 −4
Original line number Diff line number Diff line
@@ -78,13 +78,14 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth) 
	current->ret_stack[index].ret = ret;

	current->ret_stack[index].func = func;

	current->ret_stack[index].calltime = calltime;

	current->ret_stack[index].subtime = 0;

	*depth = index;



	return 0;

}



/* Retrieve a function return address to the trace stack on thread info.*/

void

static void

ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret)

{

	int index;
@@ -104,9 +105,6 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret) 
	trace->calltime = current->ret_stack[index].calltime;

	trace->overrun = atomic_read(&current->trace_overrun);

	trace->depth = index;

	barrier();

	current->curr_ret_stack--;



}



/*
@@ -121,6 +119,8 @@ unsigned long ftrace_return_to_handler(void) 
	ftrace_pop_return_trace(&trace, &ret);

	trace.rettime = trace_clock_local();

	ftrace_graph_return(&trace);

	barrier();

	current->curr_ret_stack--;



	if (unlikely(!ret)) {

		ftrace_graph_stop();