Event Tracing in the Linux kernel
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
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
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
Alright, got it. The trace is in the file /sys/kernel/debug/tracing/trace I was checking for the messages in dmesg instead. My issue. Also, enabling all the events is probably not a good idea, on my system the file does not open after enabling all the events, my guess is that there are way to many tracepoints being hit and logged. On Wed, Mar 2, 2022 at 5:57 PM David Kahurani <k.kahurani@gmail.com> wrote:
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
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.
participants (3)
-
Constantine Shulyupin -
David Kahurani -
Donald Hunter