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>
This commit is contained in:
Stephane Eranian 2012-03-08 23:47:46 +01:00 committed by Ingo Molnar
parent a5aabdacde
commit 330aa675b4
3 changed files with 17 additions and 1 deletions

View file

@ -473,6 +473,9 @@ static int __cmd_record(struct perf_record *rec, int argc, const char **argv)
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)

View file

@ -1023,6 +1023,12 @@ static int write_cpuid(int fd, struct perf_header *h __used,
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 @@ static void print_cpuid(struct perf_header *ph, int fd, FILE *fp)
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 @@ static const struct feature_ops feat_ops[HEADER_LAST_FEATURE] = {
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 {

View file

@ -27,7 +27,7 @@ enum {
HEADER_EVENT_DESC,
HEADER_CPU_TOPOLOGY,
HEADER_NUMA_TOPOLOGY,
HEADER_BRANCH_STACK,
HEADER_LAST_FEATURE,
HEADER_FEAT_BITS = 256,
};