[lttng-dev] Userspace C++ Fucntion entry exit insert tracepoints

[Antoine Busque]

On Fri, Aug 28, 2015 at 10:12 PM, Farhan Shariff
<farhan.shariff at hotmail.com> wrote:
> Hi Antoine,
>
> Thank you for your reply:)
>
> What is the major dependency or reason that lttng modules build on 2.6.38
> and higher and not on lower 2.6.32
>

There have been changes in the kernel's tracepoint API between
2.6.32 and 2.6.36, amongst other changes, causing
incompatibilities. Patches to support kernel versions lower than
2.6.36 were at one point maintained, under `linux-patches/`
within the lttng-modules source tree, but as discrepancies
between older and newer kernels grew it became too burdensome to
actively maintain them.

> btw  ‑cyg‑profile library  provides only function call graph and NOT the I/O
> arguments. I prefer using it with tracepoints();
>

Right, the generated instrumentation only has information about
the function's address and its callsite. I do not believe there are
ready-made facilities to generate similar entry/exit
instrumentation that also accounts for all the current arguments.

Also, I've added back lttng-dev in CC to this message. Please try
to keep the discussion on the public mailing list.

Regards,
Antoine Busque

>
> Best Regards
> Farhan Shariff
> Design Engineer
> Software Facilities EUV Source
> ASML Veldhoven- Netherlands
>
>
>> Date: Fri, 7 Aug 2015 13:07:49 -0400
>> Subject: Re: [lttng-dev] Userspace C++ Fucntion entry exit insert
>> tracepoints
>> From: abusque at efficios.com
>> To: farhan.shariff at hotmail.com
>> CC: lttng-dev at lists.lttng.org
>
>>
>> On Wed, Aug 5, 2015 at 10:32 AM, Farhan Shariff
>> <farhan.shariff at hotmail.com> wrote:
>> > Hi,
>> >
>> > I am working with a c++ application( userspace )
>> >
>> > I want to place in my source code
>> > - tracepoint(provide,name,...) at every function entry and exit .
>> >
>> > is it possible to by any means to automate this as it is very cumbersome
>> > to
>> > place it manually.
>> >
>> >
>> >
>> > Best Regards
>> >
>> > Farhan Shariff
>> >
>> > Farhan Shariff
>> >
>>
>> Hi,
>>
>> I suggest you have a look at the LTTng documentation on function tracing:
>>
>> http://lttng.org/docs/#doc-liblttng‑ust‑cyg‑profile
>>
>> I believe this might suit your needs.
>>
>> Regards,
>> Antoine.
>>
>> >
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>> >