perf session: Don't rely on evlist in pipe mode

Session sets a number parameters that rely on evlist. These parameters
are not used in pipe-mode and should not be set, since evlist is
unavailable. Fix that.

Signed-off-by: David Carrillo-Cisneros <davidcc@google.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Simon Que <sque@chromium.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/20170410201432.24807-6-davidcc@google.com
[ Check if file != NULL in perf_session__new(), like when used by builtin-top.c ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index a25302bc55a817ab304fe7de741670524b8c42ab..7b740a73e595eb04701bea546ff5ebdcc797edbf 100644 (file)
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -140,8 +140,14 @@ struct perf_session *perf_session__new(struct perf_data_file *file,
                        if (perf_session__open(session) < 0)
                                goto out_close;
 
-                       perf_session__set_id_hdr_size(session);
-                       perf_session__set_comm_exec(session);
+                       /*
+                        * set session attributes that are present in perf.data
+                        * but not in pipe-mode.
+                        */
+                       if (!file->is_pipe) {
+                               perf_session__set_id_hdr_size(session);
+                               perf_session__set_comm_exec(session);
+                       }
                }
        } else  {
                session->machines.host.env = &perf_env;
@@ -156,7 +162,11 @@ struct perf_session *perf_session__new(struct perf_data_file *file,
                        pr_warning("Cannot read kernel map\n");
        }
 
-       if (tool && tool->ordering_requires_timestamps &&
+       /*
+        * In pipe-mode, evlist is empty until PERF_RECORD_HEADER_ATTR is
+        * processed, so perf_evlist__sample_id_all is not meaningful here.
+        */
+       if ((!file || !file->is_pipe) && tool && tool->ordering_requires_timestamps &&
            tool->ordered_events && !perf_evlist__sample_id_all(session->evlist)) {
                dump_printf("WARNING: No sample_id_all support, falling back to unordered processing\n");
                tool->ordered_events = false;