Good news, bad news

[Charles Oliver Nutter]

fib_ruby LogCompilation inlining graph, showing that fib_ruby is not
inlined: https://gist.github.com/f2b665ad3c97ba622ebf

Can anyone suggest other flags I can try to adjust to get things to
inline better?

FWIW, the handle chain in question that's not inlining is pretty simple:

* DMH pointing back at fib_ruby
* permute args
* GWT

- Charlie

On Mon, May 23, 2011 at 4:19 PM, Charles Oliver Nutter
<headius at headius.com> wrote:
> I'm working up a set of files that show JRuby compilation output, but
> I noticed a couple things that might be interesting right now.
>
> First off, fairly early in the assembly output for fib, I see this:
>
>  0x02876d1f: call      0x0282d0e0      ; OopMap{[96]=Oop [100]=Oop
> [28]=Oop [40]=Oop [48]=Oop off=644}
>                                        ;*invokespecial invokeExact
>                                        ; -
> java.lang.invoke.MethodHandle::invokeExact at 63
>                                        ; -
> java.lang.invoke.MethodHandle::invokeExact at 23
>                                        ; -
> bench.bench_fib_recursive::method__0$RUBY$fib_ruby at 51 (line 7)
>                                        ;   {optimized virtual_call}
>
> For fib, the only invokedynamic is the recursive call to fib, so that
> would indicate that fib_ruby is not inlining into itself at all here.
> And I can't see it inlining into itself anywhere in the assembly
> output.
>
> Later in the same output:
>
>  0x0287703f: call      0x0282dba0      ; OopMap{ebp=Oop off=1444}
>                                        ;*checkcast
>                                        ; -
> java.lang.invoke.MethodHandle::invokeExact at 40
>                                        ; -
> bench.bench_fib_recursive::method__0$RUBY$fib_ruby at 82 (line 7)
>                                        ;   {runtime_call}
>  0x02877044: call      0x0105a9d0      ;*checkcast
>                                        ; -
> java.lang.invoke.MethodHandle::invokeExact at 40
>                                        ; -
> bench.bench_fib_recursive::method__0$RUBY$fib_ruby at 82 (line 7)
>                                        ;   {runtime_call}
>
> These appear repeatedly near the invokedynamic invocation above. If
> I'm reading this right, neither the recursive call nor logic involved
> in that particular handle is inlining. Am I right?
>
> Here's the complete assembly dump (i386) for the fib_ruby method:
> https://gist.github.com/987640
>
> In other news, MaxInlineSize=150 with InlineSmallCode=3000 does not
> appear to improve performance. I also tried bumping up
> MaxRecursiveInlineLevel and MaxInlineLevel with no effect.
>
> - Charlie
>