On Tue, 19 Oct 2021 22:34:54 -0400 Steven Rostedt rostedt@goodmis.org wrote:
On Wed, 20 Oct 2021 11:20:27 +0900 Masami Hiramatsu mhiramat@kernel.org wrote:
Hmm, by the way, shouldn't we set this feature by default? There are many "cat trace | grep ..." style test code in ftracetest just for checking whether the event is recorded. At least for the ftracetest, it should be set unless the testcase is explicitly disable it.
For testing, sure.
I was criticized by the BPF folks about tracing stopping when the trace file was being read. So for normal operations, it doesn't pause, because that "confuses" people (so I am told).
OK, I got it.
Here is the patch to enable it by default for ftracetest :)
Thanks!
From 61e641f494307d9942a8415bc6743e85dd95438e Mon Sep 17 00:00:00 2001
From: Masami Hiramatsu mhiramat@kernel.org Date: Wed, 20 Oct 2021 11:50:35 +0900 Subject: [PATCH] selftests/ftrace: Stop tracing while reading the trace file by default
Stop tracing while reading the trace file by default, to prevent the test results while checking it and to avoid taking a long time to check the result. If there is any testcase which wants to test the tracing while reading the trace file, please override this setting inside the test case.
Signed-off-by: Masami Hiramatsu mhiramat@kernel.org --- tools/testing/selftests/ftrace/test.d/functions | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/tools/testing/selftests/ftrace/test.d/functions b/tools/testing/selftests/ftrace/test.d/functions index 000fd05e84b1..8adc0140d03f 100644 --- a/tools/testing/selftests/ftrace/test.d/functions +++ b/tools/testing/selftests/ftrace/test.d/functions @@ -124,6 +124,12 @@ initialize_ftrace() { # Reset ftrace to initial-state [ -f uprobe_events ] && echo > uprobe_events [ -f synthetic_events ] && echo > synthetic_events [ -f snapshot ] && echo 0 > snapshot + +# Stop tracing while reading the trace file by default, to prevent +# the test results while checking it and to avoid taking a long time +# to check the result. + [ -f options/pause-on-trace ] && echo 1 > options/pause-on-trace + clear_trace enable_tracing }