perf tools: Enable overwrite settings

This patch allows following config terms and option:

Globally setting events to overwrite;

  # perf record --overwrite ...

Set specific events to be overwrite or no-overwrite.

  # perf record --event cycles/overwrite/ ...
  # perf record --event cycles/no-overwrite/ ...

Add missing config terms and update the config term array size because
the longest string length has changed.

For overwritable events, it automatically selects attr.write_backward
since perf requires it to be backward for reading.

Test result:

  # perf record --overwrite -e syscalls:*enter_nanosleep* usleep 1
  [ perf record: Woken up 2 times to write data ]
  [ perf record: Captured and wrote 0.011 MB perf.data (1 samples) ]
  # perf evlist -v
  syscalls:sys_enter_nanosleep: type: 2, size: 112, config: 0x134, { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU|PERIOD|RAW, disabled: 1, inherit: 1, mmap: 1, comm: 1, enable_on_exec: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, write_backward: 1
  # Tip: use 'perf evlist --trace-fields' to show fields for tracepoint events

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1468485287-33422-14-git-send-email-wangnan0@huawei.com
Signed-off-by: He Kuang <hekuang@huawei.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 5 insertions, 5 deletions

diff --git a/tools/perf/tests/backward-ring-buffer.c b/tools/perf/tests/backward-ring-buffer.c
index db9cd3048655..615780cbfe1d 100644
--- a/tools/perf/tests/backward-ring-buffer.c
+++ b/tools/perf/tests/backward-ring-buffer.c
@@ -108,7 +108,11 @@ int test__backward_ring_buffer(int subtest __maybe_unused)
 	}
 
 	bzero(&parse_error, sizeof(parse_error));
-	err = parse_events(evlist, "syscalls:sys_enter_prctl", &parse_error);
+	/*
+	 * Set backward bit, ring buffer should be writing from end. Record
+	 * it in aux evlist
+	 */
+	err = parse_events(evlist, "syscalls:sys_enter_prctl/overwrite/", &parse_error);
 	if (err) {
 		pr_debug("Failed to parse tracepoint event, try use root\n");
 		ret = TEST_SKIP;
@@ -117,10 +121,6 @@ int test__backward_ring_buffer(int subtest __maybe_unused)
 
 	perf_evlist__config(evlist, &opts, NULL);
 
-	/* Set backward bit, ring buffer should be writing from end */
-	evlist__for_each_entry(evlist, evsel)
-		evsel->attr.write_backward = 1;
-
 	err = perf_evlist__open(evlist);
 	if (err < 0) {
 		pr_debug("perf_evlist__open: %s\n",