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Re: thoughts [re LTT]
Frank Ch. Eigler wrote:
> This is quite clever, but addresses a different clientele. LTT-type
> techniques may be sufficient iff:
>
> - one may patch one's kernel with the tracing infrastructure
> - the set of trace event points are all hard-coded
> - the data made available at those points are all hard-coded
> - the computation performed upon those data/events is limited to
> little besides filtering / printing
I think this misses the point. Mathieu's lttv is mechanism-agnostic.
In fact, it can read any format as long as you provide it with the
XML description of it. That's why creating a new tracing tool
just doesn't make any sense.
In as far as static instrumentation is concerned, it's as old as
programming, every body does it. It's nice to be able to add stuff
dynamically, but a quick browse around the kernel sources should
rapidely reveal how widespread static instrumentation already is.
In general, some kernel developers had shown resistence to static
trace points, but it's beyond me that some people in the tools
development crowd are still stuck on this issue while many kernel
developers (including Andrew) themselves now acknowledge that trace
points such as those provided by LTT are not a problem.
IOW, there's just no point having a debate about static vs.
dynamic instrumentation, the issue is a pointless.
Karim
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