Hi, Adrian - On Sat, Jul 07, 2007 at 07:01:57PM +0200, Adrian Bunk wrote: > [...] > > Things are not so simple. One might not know that one has a > > performance problem until one tries some analysis tools. Rebooting > > into different kernels just to investigate does not work generally [...] > > I'm not getting this: > > You'll only start looking into an analysis tool if you have a > performance problem, IOW if you are not satisfied with the > performance.
There may be people whose jobs entail continually suspecting performance problems. Or one may run instrumentation code on a long-term basis specifically to locate performance spikes. > And the debug code will not have been tested on this machine no matter > whether it's enabled through a compile option or at runtime. There is a big difference in favour of the former. The additional instrumentation code may be small enough to inspect carefully. The rest of the kernel would be unaffected. > [...] If you might be able to get a big part of tracing and other > debug code enabled with a performance penalty of a few percent of > _kernel_ performance, then you might get much debugging aid without > any effective impact on application performance. Agreed. - FChE - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
