* Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > On Wed, May 10, 2017 at 10:32:06AM +0200, Jiri Slaby wrote: > > > But it does hurt, in the sense that the complicated format of DWARF CFI > > > means the unwinder has to jump through a lot more hoops to read it. > > > > Why that matters, actually? Unwinder is nothing to be performance > > oriented. And if somebody is doing a lot of unwinding during runtime, > > they can switch to in-this-case-faster FP unwinder. > > perf (and ftrace) like the unwinder to be considered performance > oriented. Yes, and given how critical debugging is there's a kind of useful synergy here: overall the perf unwinder is run about 10 orders of magnitude more often than the debugging unwinder, so it's a very big help in shaking out unwinder/debug-info bugs and increasing robustness overall. The 'price' for using the unwinder in perf is that it has to be fast. Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe live-patching" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
