2022-02-14 09:33:59

by Krzysztof Kozlowski

[permalink] [raw]
Subject: [PATCH v3] selftests/ftrace: Do not trace do_softirq because of PREEMPT_RT

The PREEMPT_RT patchset does not use do_softirq() function thus trying
to filter for do_softirq fails for such kernel:

echo do_softirq
ftracetest: 81: echo: echo: I/O error

Choose some other visible function for the test. The function does not
have to be actually executed during the test, because it is only testing
filter API interface.

Signed-off-by: Krzysztof Kozlowski <[email protected]>
Reviewed-by: Shuah Khan <[email protected]>
Reviewed-by: Steven Rostedt (VMware) <[email protected]>

---

Changes since v2:
1. Rephrase commit msg, after comments from Sebastian.
2. Add review tag.

Changes since v1:
1. Use scheduler_tick.
2. Add review tag.

Notes:
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..25432b8cd5bd 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="scheduler_tick"

ALL_FUNCS="#### all functions enabled ####"

--
2.32.0


2022-02-14 21:09:40

by Shuah Khan

[permalink] [raw]
Subject: Re: [PATCH v3] selftests/ftrace: Do not trace do_softirq because of PREEMPT_RT

On 2/14/22 4:19 AM, Sebastian Andrzej Siewior wrote:
> On 2022-02-14 09:36:57 [+0100], Krzysztof Kozlowski wrote:
>> The PREEMPT_RT patchset does not use do_softirq() function thus trying
>> to filter for do_softirq fails for such kernel:
>>
>> echo do_softirq
>> ftracetest: 81: echo: echo: I/O error
>>
>> Choose some other visible function for the test. The function does not
>> have to be actually executed during the test, because it is only testing
>> filter API interface.
>>
>> Signed-off-by: Krzysztof Kozlowski <[email protected]>
>> Reviewed-by: Shuah Khan <[email protected]>
>> Reviewed-by: Steven Rostedt (VMware) <[email protected]>
>
> Acked-by: Sebastian Andrzej Siewior <[email protected]>
>
>> Notes:
>> I understand that the failure does not exist on mainline kernel (only
>> with PREEMPT_RT patchset) but the change does not harm it.
>

Steve,

Would you like me to take this through linux-kselftest next for 5.18-rc1

I am guessing there is no urgency on this - of not I can take this in for
rc5.

thanks,
-- Shuah

Subject: Re: [PATCH v3] selftests/ftrace: Do not trace do_softirq because of PREEMPT_RT

On 2022-02-14 09:36:57 [+0100], Krzysztof Kozlowski wrote:
> The PREEMPT_RT patchset does not use do_softirq() function thus trying
> to filter for do_softirq fails for such kernel:
>
> echo do_softirq
> ftracetest: 81: echo: echo: I/O error
>
> Choose some other visible function for the test. The function does not
> have to be actually executed during the test, because it is only testing
> filter API interface.
>
> Signed-off-by: Krzysztof Kozlowski <[email protected]>
> Reviewed-by: Shuah Khan <[email protected]>
> Reviewed-by: Steven Rostedt (VMware) <[email protected]>

Acked-by: Sebastian Andrzej Siewior <[email protected]>

> Notes:
> I understand that the failure does not exist on mainline kernel (only
> with PREEMPT_RT patchset) but the change does not harm it.

Yes, and now it does not sound (to me) like duct tape. Thank you.

> If it is not suitable alone, please consider it for RT patchset.

We trying to get it merged so…

Sebastian

2022-02-14 21:23:30

by Steven Rostedt

[permalink] [raw]
Subject: Re: [PATCH v3] selftests/ftrace: Do not trace do_softirq because of PREEMPT_RT

On Mon, 14 Feb 2022 11:33:18 -0700
Shuah Khan <[email protected]> wrote:

> Steve,
>
> Would you like me to take this through linux-kselftest next for 5.18-rc1
>
> I am guessing there is no urgency on this - of not I can take this in for
> rc5.

Hi Shuah,

Feel free to take it through your tree in any urgent level you like.

Reviewed-by: Steven Rostedt (Google) <[email protected]>

-- Steve