Re: igc statistics display

["Gerd Möllmann" <gerd.moellmann@gmail.com>]

Helmut Eller <eller.helmut@gmail.com> writes:

> On Fri, Jan 10 2025, Gerd Möllmann wrote:
>
>> Eli Zaretskii <eliz@gnu.org> writes:
>>> SystemTap is not the ideal means for such a facility.  Its only
>>> significant advantage is that it's supported by GDB.  But its huge
>>> disadvantage is that it's a Linux-only facility.
>
> I think drrace is also available for Windows.
>
>>> In addition, I feel that this is too low-level for our purposes.  We
>>> need something more akin to trace-redisplay.
>>
>> I must say upfront that I've only read about dtrace for a couple hours
>> and asked Gemini a few questions. From that, my understanding is that an
>> application can generate its own application-specific events that carry
>> additional data, including strings, int, floats, and so on, structs (not
>> sure if I believe Gemini in that case, but who knows). (Helmut, please
>> correct me if that's wrong.)
>
> Applications can define "static trace points".  In practice, that means
> the application has macro calls like DTRACE_PROBE(name, arg1, arg2..)
> in the source code at interesting places.  Obviously, the same macro
> could be configured to work with dtrace or systemtap or something else.
>
> An advantage of tools like dtrace and systemtap is that they can patch
> code: static trace points are nop instructions, until activated.  So
> very cheap, if not used.  Ironically, that's almost impossible to do by
> the application itself.
>
> Static trace points are useful, but with dtrace/systemtap it's also
> possible to set trace points by line number, as in gdb.
>
> Helmut

Thanks, very interesginb!