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: Adrian 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: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/thread-stack.c b/tools/perf/util/thread-stack.c
index e3f7dfecafa9b352431e5fbc731f3ebbece39aa6..c091635bf7dcb317d66f1ab8273e5cc90678c5e1 100644 (file)
--- a/tools/perf/util/thread-stack.c
+++ b/tools/perf/util/thread-stack.c
@@ -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;