Event Tracing in the Linux kernel

Event Tracing in the Linux kernel

[David Kahurani]

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Hello,

I have compiled a pretty recent Linux kernel mostly basing the
configuration on the older kernel.

I am now testing out the event tracing system but seem to be having a
problem.

Having enabled all events with

# echo *:* > /sys/kernel/debug/tracing/set_event

As described here [1], I expect that dmesg shows me some traces but there
aren't any. My dmesg logs are empty(just the same as with not having
enabled the events).

What could I be missing? Am I checking the wrong place for the trace? Are
there no tracepoints getting hit?

Any hits and pointers would be much appreciated.

Regards,
David

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Re: Event Tracing in the Linux kernel

[Constantine Shulyupin]

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Please check
https://www.kernel.org/doc/html/latest/trace/events.html

On Wed, 2 Mar 2022 at 16:38, David Kahurani <k.kahurani@gmail.com> wrote:

> Hello,
>
> I have compiled a pretty recent Linux kernel mostly basing the
> configuration on the older kernel.
>
> I am now testing out the event tracing system but seem to be having a
> problem.
>
> Having enabled all events with
>
> # echo *:* > /sys/kernel/debug/tracing/set_event
>
> As described here [1], I expect that dmesg shows me some traces but there
> aren't any. My dmesg logs are empty(just the same as with not having
> enabled the events).
>
> What could I be missing? Am I checking the wrong place for the trace? Are
> there no tracepoints getting hit?
>
> Any hits and pointers would be much appreciated.
>
> Regards,
> David
>
>
>
>
>
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies@kernelnewbies.org
> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>


-- 
Constantine Shulyupin

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Re: Event Tracing in the Linux kernel

[David Kahurani]

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Yes, I am using that reference but since no tracepoints are being hit, it
leaves me confused.

On Wed, Mar 2, 2022 at 5:53 PM Constantine Shulyupin <
constantine.shulyupin@gmail.com> wrote:

> Please check
> https://www.kernel.org/doc/html/latest/trace/events.html
>
> On Wed, 2 Mar 2022 at 16:38, David Kahurani <k.kahurani@gmail.com> wrote:
>
>> Hello,
>>
>> I have compiled a pretty recent Linux kernel mostly basing the
>> configuration on the older kernel.
>>
>> I am now testing out the event tracing system but seem to be having a
>> problem.
>>
>> Having enabled all events with
>>
>> # echo *:* > /sys/kernel/debug/tracing/set_event
>>
>> As described here [1], I expect that dmesg shows me some traces but there
>> aren't any. My dmesg logs are empty(just the same as with not having
>> enabled the events).
>>
>> What could I be missing? Am I checking the wrong place for the trace? Are
>> there no tracepoints getting hit?
>>
>> Any hits and pointers would be much appreciated.
>>
>> Regards,
>> David
>>
>>
>>
>>
>>
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies@kernelnewbies.org
>> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>
>
>
> --
> Constantine Shulyupin
>

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Re: Event Tracing in the Linux kernel

[Donald Hunter]

David Kahurani <k.kahurani@gmail.com> writes:

> Yes, I am using that reference but since no tracepoints are being hit, it leaves me confused.

I think you need to cat /sys/kernel/debug/tracing/trace_pipe as mentioned in
https://www.kernel.org/doc/html/latest/trace/tracepoint-analysis.html

Regards,
Donald.

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