ftrace: add tracer called branch

Impact: added new branch tracer

Currently the tracing of branch profiling (unlikelys and likelys hit)
is only activated by the iter_ctrl. This patch adds a tracer called
"branch" that will just trace the branch profiling. The advantage
of adding this tracer is that it can be added to the ftrace selftests
on startup.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 23 insertions, 0 deletions

diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 0728a105dcc1..24e6e075e6d6 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -13,6 +13,7 @@ static inline int trace_valid_entry(struct trace_entry *entry)
         case TRACE_STACK:
         case TRACE_PRINT:
         case TRACE_SPECIAL:
+        case TRACE_BRANCH:
                 return 1;
         }
         return 0;
@@ -544,3 +545,25 @@ trace_selftest_startup_sysprof(struct tracer *trace, struct trace_array *tr)
         return ret;
 }
 #endif /* CONFIG_SYSPROF_TRACER */
+
+#ifdef CONFIG_BRANCH_TRACER
+int
+trace_selftest_startup_branch(struct tracer *trace, struct trace_array *tr)
+{
+        unsigned long count;
+        int ret;
+
+        /* start the tracing */
+        trace->init(tr);
+        /* Sleep for a 1/10 of a second */
+        msleep(100);
+        /* stop the tracing. */
+        tracing_stop();
+        /* check the trace buffer */
+        ret = trace_test_buffer(tr, &count);
+        trace->reset(tr);
+        tracing_start();
+
+        return ret;
+}
+#endif /* CONFIG_BRANCH_TRACER */