Commit 2dcde4e1 authored by Adrian Hunter's avatar Adrian Hunter Committed by Arnaldo Carvalho de Melo
Browse files

perf tools: Improve thread_stack__process() for trace begin / end 



thread_stack__process() is used to create call paths for database
export.  Improve the handling of trace begin / end to allow for a trace
that ends in a call.

Previously, the Intel PT decoder would indicate begin / end by a branch
from / to zero. That hides useful information, in particular when a
trace ends with a call. Before remedying that, enhance the thread stack
so that it identifies the trace end by the flag instead of by ip == 0.

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20180920130048.31432-5-adrian.hunter@intel.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 4d60e5e3

tools/perf/util/thread-stack.c

+9 −7
Original line number Diff line number Diff line
@@ -357,7 +357,7 @@ void call_return_processor__free(struct call_return_processor *crp) 


static int thread_stack__push_cp(struct thread_stack *ts, u64 ret_addr,

				 u64 timestamp, u64 ref, struct call_path *cp,

				 bool no_call)

				 bool no_call, bool trace_end)

{

	struct thread_stack_entry *tse;

	int err;
@@ -375,6 +375,7 @@ static int thread_stack__push_cp(struct thread_stack *ts, u64 ret_addr, 
	tse->branch_count = ts->branch_count;

	tse->cp = cp;

	tse->no_call = no_call;

	tse->trace_end = trace_end;



	return 0;

}
@@ -448,7 +449,7 @@ static int thread_stack__bottom(struct thread *thread, struct thread_stack *ts, 
		return -ENOMEM;



	return thread_stack__push_cp(thread->ts, ip, sample->time, ref, cp,

				     true);

				     true, false);

}



static int thread_stack__no_call_return(struct thread *thread,
@@ -480,7 +481,7 @@ static int thread_stack__no_call_return(struct thread *thread, 
			if (!cp)

				return -ENOMEM;

			return thread_stack__push_cp(ts, 0, sample->time, ref,

						     cp, true);

						     cp, true, false);

		}

	} else if (thread_stack__in_kernel(ts) && sample->ip < ks) {

		/* Return to userspace, so pop all kernel addresses */
@@ -505,7 +506,7 @@ static int thread_stack__no_call_return(struct thread *thread, 
		return -ENOMEM;



	err = thread_stack__push_cp(ts, sample->addr, sample->time, ref, cp,

				    true);

				    true, false);

	if (err)

		return err;
@@ -525,7 +526,7 @@ static int thread_stack__trace_begin(struct thread *thread, 


	/* Pop trace end */

	tse = &ts->stack[ts->cnt - 1];

	if (tse->cp->sym == NULL && tse->cp->ip == 0) {

	if (tse->trace_end) {

		err = thread_stack__call_return(thread, ts, --ts->cnt,

						timestamp, ref, false);

		if (err)
@@ -554,7 +555,7 @@ static int thread_stack__trace_end(struct thread_stack *ts, 
	ret_addr = sample->ip + sample->insn_len;



	return thread_stack__push_cp(ts, ret_addr, sample->time, ref, cp,

				     false);

				     false, true);

}



int thread_stack__process(struct thread *thread, struct comm *comm,
@@ -604,6 +605,7 @@ int thread_stack__process(struct thread *thread, struct comm *comm, 
	ts->last_time = sample->time;



	if (sample->flags & PERF_IP_FLAG_CALL) {

		bool trace_end = sample->flags & PERF_IP_FLAG_TRACE_END;

		struct call_path_root *cpr = ts->crp->cpr;

		struct call_path *cp;

		u64 ret_addr;
@@ -621,7 +623,7 @@ int thread_stack__process(struct thread *thread, struct comm *comm, 
		if (!cp)

			return -ENOMEM;

		err = thread_stack__push_cp(ts, ret_addr, sample->time, ref,

					    cp, false);

					    cp, false, trace_end);

	} else if (sample->flags & PERF_IP_FLAG_RETURN) {

		if (!sample->ip || !sample->addr)

			return 0;

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