Messages in this thread | | | Date | Mon, 18 Sep 2006 06:32:48 +0200 | From | Ingo Molnar <> | Subject | Re: tracepoint maintainance models |
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* Karim Yaghmour <karim@opersys.com> wrote:
> Theodore Tso wrote: > > I *think* what Karim is trying to claim is that LTT also has some > > dynamic capabilities, and isn't a pure static tracing system. But if > > that's the case, I don't understand why LTT and SystemTap can't just > > merge and play nice together.... > > That's been the thrust of my intervention here. [...]
indeed, and i severely misunderstood your points in this regard. Now i have re-read some of your earlier points, and in particular:
>> And finally, do realize that in 2000 I personally contacted the head >> of the DProbes project IBM in order to foster common development, >> following which ltt was effectively modified in order to allow >> dynamic instrumentation of the kernel ...
and now i'm red faced - i was wrong about this fundamental aspect of your position. Please accept my apologies!
so regarding the big picture we are largely on the same page in essence i think - sub-issues non-withstanding :-) As long as LTT comes with a facility that allows the painless moving of a static LTT markup to a SystemTap script, that would come quite a bit closer to being acceptable for upstream acceptance in my opinion.
The curious bit is: why doesnt LTT integrate SystemTap yet? Is it the performance aspect? Some of the extensive hooking you do in LTT could be aleviated to a great degree if you used dynamic probes. For example the syscall entry hackery in LTT looks truly scary. I cannot understand that someone who does tracing doesnt see the fundamental strength of SystemTap - i think that in part must have lead to my mistake of assuming that you opposed SystemTap.
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