Messages in this thread | | | Date | Sat, 7 Jul 2007 04:25:26 +0200 | From | Adrian Bunk <> | Subject | Re: [patch 10/10] Scheduler profiling - Use immediate values |
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On Fri, Jul 06, 2007 at 07:43:15PM -0400, Mathieu Desnoyers wrote: > * Adrian Bunk (bunk@stusta.de) wrote: > > On Fri, Jul 06, 2007 at 06:14:10PM -0400, Chuck Ebbert wrote: > > > On 07/06/2007 07:44 AM, Andi Kleen wrote: > > > > I think the optimization is a good idea, although i dislike it > > > > that it is complicated for the dynamic markers. If it was just > > > > static it would be much simpler. > > > > > > Another thing to consider is that there might be hundreds of these > > > probes/tracepoints active in an instrumented kernel. The overhead > > > adds up fast, so the gain may be worth all the pain. > > > > Only if you want to squeeze the last bit of performance out of > > _debugging_ functionality. > > > > You avoid all the pain if you simply don't use debugging functionality > > on production systems. > > > > Adrian, > > Please have a look at my markers posts, especially: > > http://www.ussg.iu.edu/hypermail/linux/kernel/0707.0/0669.html > > And also look into OLS 2007 proceedings for Martin Bligh's paper on > Debugging Google sized clusters. It basically makes the case for adding > functionnality to debug _user space_ problems on production systems that > can be turned on dynamically.
Using a different kernel for tracing still fulfills all the requirements listed in section 5 of your paper...
> Mathieu
cu Adrian
--
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