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/util/header.c b/tools/perf/util/header.c
index c851495..0d9b6da 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1023,6 +1023,12 @@
return do_write_string(fd, buffer);
}
+static int write_branch_stack(int fd __used, struct perf_header *h __used,
+ struct perf_evlist *evlist __used)
+{
+ return 0;
+}
+
static void print_hostname(struct perf_header *ph, int fd, FILE *fp)
{
char *str = do_read_string(fd, ph);
@@ -1315,6 +1321,12 @@
free(str);
}
+static void print_branch_stack(struct perf_header *ph __used, int fd __used,
+ FILE *fp)
+{
+ fprintf(fp, "# contains samples with branch stack\n");
+}
+
static int __event_process_build_id(struct build_id_event *bev,
char *filename,
struct perf_session *session)
@@ -1519,6 +1531,7 @@
FEAT_OPA(HEADER_CMDLINE, cmdline),
FEAT_OPF(HEADER_CPU_TOPOLOGY, cpu_topology),
FEAT_OPF(HEADER_NUMA_TOPOLOGY, numa_topology),
+ FEAT_OPA(HEADER_BRANCH_STACK, branch_stack),
};
struct header_print_data {