Re: [PATCH 0/11] LTTng-core (basic tracing infrastructure) 0.5.108

[Tim Bird <tim.bird@am.sony.com>]

Thomas Gleixner wrote:
> On Fri, 2006-09-15 at 21:10 +0200, Roman Zippel wrote:
> 
>>>this is being worked on actively: there's the "djprobes" patchset, which 
>>>includes a simplified disassembler to analyze common target code and can 
>>>thus insert much faster, call-a-trampoline-function based tracepoints 
>>>that are just as fast as (or faster than) compile-time, static 
>>>tracepoints.
>>
>>Who is going to implement this for every arch?
>>Is this now the official party line that only archs, which implement all 
>>of this, can make use of efficient tracing?
>  
> In the reverse you are enforcing an ugly - but available for all archs -
> solution due to the fact that there is nobody interested enough to
> implement it ?

????

If there's a solution people are willing to implement, and one
they aren't - doesn't that say something?  Static tracepoint
patches for numerous architectures have existed and been maintained
out-of-tree for years.

> If there is no interest to do that, then this arch can probably live w/o
> instrumentation for the next decade too.

The arches already have instrumentation - just not dynamic 
instrumentation.  The reason static tracepoints have been
implemented and kprobes haven't is that static tracepoints
are sufficient for what those people are doing, and dynamic
tracepoints are a pain to implement.

Let me repeat that, just in case people missed it:
"Static tracepoints work for what I need."  If other people
want to implement something fancier that works for them,
then feel free.

=============================
Tim Bird
Architecture Group Chair, CE Linux Forum
Senior Staff Engineer, Sony Electronics
=============================