[lttng-dev] LTTng event loglevel

[lttng-dev] LTTng event loglevel

[Jeffrey Chen]

Hi:

I am reading the LTTng and I am confused about the loglevel in the document. The document talked about it could assign a loglevel to each event. (http://lttng.org/docs/#doc-assigning-log-levels) But, later in the document, it says all events from LTTng are traced as loglevel TRACE_DEBUG_FUNCTION. (http://lttng.org/docs/#doc-liblttng%E2%80%91ust%E2%80%91cyg%E2%80%91profile) So, which is right? Can I assign loglevel to user level traces? Thanks.
 		 	   		  
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[lttng-dev] LTTng event loglevel

[Alexandre Montplaisir]

Hi,

On 2015-06-22 05:06 PM, Jeffrey Chen wrote:
> Hi:
>
> I am reading the LTTng and I am confused about the loglevel in the document. The document talked about it could assign a loglevel to each event. (http://lttng.org/docs/#doc-assigning-log-levels)

This part refers to when you define your own tracepoints in your pogram, 
using the TRACEPOINT_EVENT macro.

>   But, later in the document, it says all events from LTTng are traced as loglevel TRACE_DEBUG_FUNCTION. (http://lttng.org/docs/#doc-liblttng%E2%80%91ust%E2%80%91cyg%E2%80%91profile)

That part however, refers to using the liblttng-ust-cyg-profile library, 
to automatically instrument function entries and exits. This library 
implements the callbacks expected by cyg-profile, and puts the 
information into UST tracepoints. Since it's this 
liblttng-ust-cyg-profile library that "defines" the tracepoints here, 
they are stuck at the log level specified in their definition, which is 
TRACE_DEBUG_FUNCTION in this case.


Hope this helps,
Alexandre

[lttng-dev] LTTng event loglevel

[Jeffrey Chen]

Thanks for your answer.

I tried to use the TRACEPOINT_LOGLEVEL macro, but I was not able to make it working. I have my macro immediately follow my TRACE_EVENT macro "TRACEPOINT_LOGLEVEL(hello_world,my_first_tracepoint,TRACE_WARNING)"

I enabled the event with the --loglevel TRACE_WARNING parameter. When I run my code, and I do `lttng list --userspace`, I still get "hello_world:my_first_tracepoint (loglevel: TRACE_DEBUG_LINE (13)) (type: tracepoint)"

It looks like my code does not set the loglevel correctly, so it is still using the default loglevel. Am I doing anything wrong? Thanks.

> Date: Mon, 22 Jun 2015 17:20:35 -0400
> From: alexmonthy@voxpopuli.im
> To: cpthk at hotmail.com
> CC: lttng-dev at lists.lttng.org
> Subject: Re: [lttng-dev] LTTng event loglevel
> 
> Hi,
> 
> On 2015-06-22 05:06 PM, Jeffrey Chen wrote:
> > Hi:
> >
> > I am reading the LTTng and I am confused about the loglevel in the document. The document talked about it could assign a loglevel to each event. (http://lttng.org/docs/#doc-assigning-log-levels)
> 
> This part refers to when you define your own tracepoints in your pogram, 
> using the TRACEPOINT_EVENT macro.
> 
> >   But, later in the document, it says all events from LTTng are traced as loglevel TRACE_DEBUG_FUNCTION. (http://lttng.org/docs/#doc-liblttng%E2%80%91ust%E2%80%91cyg%E2%80%91profile)
> 
> That part however, refers to using the liblttng-ust-cyg-profile library, 
> to automatically instrument function entries and exits. This library 
> implements the callbacks expected by cyg-profile, and puts the 
> information into UST tracepoints. Since it's this 
> liblttng-ust-cyg-profile library that "defines" the tracepoints here, 
> they are stuck at the log level specified in their definition, which is 
> TRACE_DEBUG_FUNCTION in this case.
> 
> 
> Hope this helps,
> Alexandre
> 
 		 	   		  
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