perf record: Add HEADER_BRANCH_STACK tag
This patch adds a new feature bit, namely,
HEADER_BRANCH_STACK. When present, it indicates
that sample records may contain branch stack.
This could be useful to a viewer to switch to
branch mode without having to parse all the
samples or without a specific cmdline option.
This will be used in a subsequent patch to
enhance perf report with branch stacks.
Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: acme@redhat.com
Cc: asharma@fb.com
Cc: ravitillo@lbl.gov
Cc: vweaver1@eecs.utk.edu
Cc: khandual@linux.vnet.ibm.com
Cc: dsahern@gmail.com
Link: http://lkml.kernel.org/r/1331246868-19905-3-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index a7c53a9..be4e1ee 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -473,6 +473,9 @@
if (!have_tracepoints(&evsel_list->entries))
perf_header__clear_feat(&session->header, HEADER_TRACE_INFO);
+ if (!rec->opts.branch_stack)
+ perf_header__clear_feat(&session->header, HEADER_BRANCH_STACK);
+
if (!rec->file_new) {
err = perf_session__read_header(session, output);
if (err < 0)
