On Fri, 9 Nov 2018 10:41:37 -0600 Josh Poimboeuf <jpoim...@redhat.com> wrote:
> On Fri, Nov 09, 2018 at 09:21:39AM -0600, Josh Poimboeuf wrote: > > On Fri, Nov 09, 2018 at 07:16:17AM -0800, Andy Lutomirski wrote: > > > On Thu, Nov 8, 2018 at 11:28 PM Ingo Molnar <mi...@kernel.org> wrote: > > > > > > > > > > > > All other usecases are bonus, but it would certainly be interesting to > > > > investigate the impact of using these APIs for tracing: that too is a > > > > feature enabled everywhere but utilized only by a small fraction of > > > > Linux > > > > users - so literally every single cycle or instruction saved or hot-path > > > > shortened is a major win. > > > > > > For tracing, we'd want static_call_set_to_nop() or something like that, > > > right? > > > > Are we talking about tracepoints? Or ftrace? > > Since ftrace changes calls to nops, and vice versa, I assume you meant > ftrace. I don't think ftrace is a good candidate for this, as it's > inherently more flexible than this API would reasonably allow. > Not sure what Andy was talking about, but I'm currently implementing tracepoints to use this, as tracepoints use indirect calls, and are a prime candidate for static calls, as I showed in my original RFC of this feature. -- Steve