On 10/02/2022 06:00, Steven Rostedt wrote:
On Wed, 9 Feb 2022 17:24:30 +0100 Krzysztof Kozlowski krzysztof.kozlowski@canonical.com wrote:
The PREEMPT_RT patchset does not use soft IRQs thus trying to filter for do_softirq fails for such kernel:
echo do_softirq ftracetest: 81: echo: echo: I/O error
Choose some other externally visible function for the test.
Signed-off-by: Krzysztof Kozlowski krzysztof.kozlowski@canonical.com
I understand that the failure does not exist on mainline kernel (only with PREEMPT_RT patchset) but the change does not harm it.
If it is not suitable alone, please consider it for RT patchset.
.../selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc b/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc index e96e279e0533..1d0c7601865f 100644 --- a/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc +++ b/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc @@ -19,7 +19,7 @@ fail() { # mesg FILTER=set_ftrace_filter FUNC1="schedule" -FUNC2="do_softirq" +FUNC2="_printk"
The problem with the above, is that it is not guaranteed to trigger (and probably will not), where as the do_softirq is. The filtering is suppose to trace something that actually happens.
How about using: scheduler_tick ?
This works as well. I had impression that the test is only about filtering interface and actual function does not have to hit/trigger.
I'll send v2 with scheduler_tick.
Best regards, Krzysztof