On Wed, Mar 30, 2016 at 12:43:27PM +0200, Ingo Molnar wrote: > > * Arnaldo Carvalho de Melo <[email protected]> wrote: > > > From: Andi Kleen <[email protected]> > > > > Add autoprobing for the udev86 disassembler library. > > So the typo in the title is confusing, what is 'udev86'?
Agreed, it's confusing. It was meant to be udis86. http://udis86.sourceforge.net The next patch that uses it had the URL too, but that didn't make it when this patch was split off. > > Also, this library does not seem to be available on stock Ubuntu. We should > not be > adding library dependencies that cannot be resolved on major distros: > > ... get_cpuid: [ on ] > ... bpf: [ on ] > ... udis86: [ OFF ] It's a chicken'n'egg problem. Likely when perf needs it they will add it soon. For now it's fairly easy to install manually. Using a real disassembler in perf has a lot of advantages over objdump. It allows full instruction traces with PT, which is useful for debugging. It also allows hot path analysis of branch mispredictions and automatic micro benchmarks using LBRs (implemented inn https://lkml.org/lkml/2016/3/28/331). Possibly more in the future. -Andi
