[PATCH 32/55] perf record: Add '--timestamp-filename' option to append timestamp to output filename

[Wang Nan]

This options append current timestamp to output. For example:

 # perf record -a --timestamp-filename
 ^C[ perf record: Woken up 1 times to write data ]
 [ perf record: Dump perf.data.2015122622265847 ]
 [ perf record: Captured and wrote 0.742 MB perf.data (90 samples) ]
 # ls
 perf.data.201512262226584

After 'perf record' support generating multiple output files, timestamp
would be useful to identify each of them.

Signed-off-by: Wang Nan <wangn...@huawei.com>
Signed-off-by: He Kuang <heku...@huawei.com>
Cc: Arnaldo Carvalho de Melo <a...@redhat.com>
Cc: Jiri Olsa <jo...@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu...@hitachi.com>
Cc: Namhyung Kim <namhy...@kernel.org>
Cc: Zefan Li <lize...@huawei.com>
Cc: pi3or...@163.com
---
 tools/perf/builtin-record.c | 47 +++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 45 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 2411c37..e5714b6 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -54,6 +54,7 @@ struct record {
        bool                    no_buildid_cache;
        bool                    no_buildid_cache_set;
        bool                    buildid_all;
+       bool                    timestamp_filename;
        unsigned long long      samples;
 };
 
@@ -526,6 +527,37 @@ record__finish_output(struct record *rec)
        return;
 }
 
+static int
+record__switch_output(struct record *rec, bool at_exit)
+{
+       struct perf_data_file *file = &rec->file;
+       int fd, err;
+
+       /* Same Size:      "2015122520103046"*/
+       char timestamp[] = "InvalidTimestamp";
+
+       rec->samples = 0;
+       record__finish_output(rec);
+       err = fetch_current_timestamp(timestamp, sizeof(timestamp));
+       if (err) {
+               pr_err("Failed to get current timestamp\n");
+               return -EINVAL;
+       }
+
+       fd = perf_data_file__switch(file, timestamp,
+                                   rec->session->header.data_offset,
+                                   at_exit);
+       if (fd >= 0 && !at_exit) {
+               rec->bytes_written = 0;
+               rec->session->header.data_size = 0;
+       }
+
+       if (!quiet)
+               fprintf(stderr, "[ perf record: Dump %s.%s ]\n",
+                       file->path, timestamp);
+       return fd;
+}
+
 static volatile int workload_exec_errno;
 
 /*
@@ -853,8 +885,17 @@ out_child:
        /* this will be recalculated during process_buildids() */
        rec->samples = 0;
 
-       if (!err)
-               record__finish_output(rec);
+       if (!err) {
+               if (!rec->timestamp_filename) {
+                       record__finish_output(rec);
+               } else {
+                       fd = record__switch_output(rec, true);
+                       if (fd < 0) {
+                               status = fd;
+                               goto out_delete_session;
+                       }
+               }
+       }
 
        if (!err && !quiet) {
                char samples[128];
@@ -1237,6 +1278,8 @@ struct option __record_options[] = {
                   "file", "vmlinux pathname"),
        OPT_BOOLEAN(0, "buildid-all", &record.buildid_all,
                    "Record build-id of all DSOs regardless of hits"),
+       OPT_BOOLEAN(0, "timestamp-filename", &record.timestamp_filename,
+                   "append timestamp to output filename"),
        OPT_END()
 };
 
-- 
1.8.3.4