> > For -fpatchable-function-entries I switched > > off IPA-RA, as especially on RISC there's _nothing_ you can do between > > functions without at least one scratch reg. But for live patching, I'd like > > the kernel to be compiled in the first place with 100% ABI adherence, IOW > > all IPA optimisations turned off. Does anyone have numbers on the > > performance > > impact? > > I agree that would be the best option. > > I don't think anyone has measured it because we don't know how to get > the compiler to do that :-) My guess is that it will be something close > to negligible.
I asked Nicolai to do some performance testing with all the options that could be disabled disabled. Miroslav
