Messages in this thread | | | Date | Mon, 18 Sep 2006 01:27:14 +0200 | From | Ingo Molnar <> | Subject | Re: tracepoint maintainance models |
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* Roman Zippel <zippel@linux-m68k.org> wrote:
> What is so special between users of dynamic and static tracers, that > the former will never complain, if some tracepoint doesn't work > anymore?
If by breakage you mean accidental regressions, i was not talking about accidental breakages when i suggested that dynamic tracers would not see them. The "breakage" i talked about, and which would cause regressions to static tracer users but would not be noticed by dynamic tracer users was:
_the moving of a static marker to a dynamic script_
(see <20060915204812.GA6909@elte.hu>, my first paragraph there. Also see <20060917143623.GB15534@elte.hu> for the same topic.)
this breaks static tracers, but dynamic tracers remain unaffected, because the dynamic probe (or the function attribute) still offers equivalent functionality. Hence users of dynamic tracers still have the same functionality - while users of static tracers see breakage. Ok?
If you meant accidental breakages, then of course users of both types of tracers would be affected, but even in this case there's a more subtle difference here, which i explained in <20060917143623.GB15534@elte.hu>:
>> In fact, with dynamic tracers, an end-user visible breakage can even >> be fixed _after the main kernel has been released, compiled and >> booted on the end-user's system_. Systemtap scripts can be updated on >> live systems. So there is very, very little maintainance pressure >> caused by dynamic tracing.
i hope this explains.
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