review for 7071307: MethodHandle bimorphic inlining should consider the frequency (original) (raw)

Tom Rodriguez tom.rodriguez at oracle.com
Fri Jul 29 10:24:25 PDT 2011

On Jul 28, 2011, at 6:03 PM, Vladimir Kozlov wrote:

Tom,

I think you need to check which path has IfTrue project to apply probability from IfNode.

I originally had code to do that but I convinced myself it wasn't needed though now I can't imagine what I was thinking. Currently these if's are all structured such that they don't need to be swapped but there's no reason they couldn't be. I've updated the webrev.

tom

Vladimir Tom Rodriguez wrote: http://cr.openjdk.java.net/~never/7071307 46 lines changed: 27 ins; 6 del; 13 mod; 3568 unchg 7071307: MethodHandle bimorphic inlining should consider the frequency Reviewed-by: The fix for 7050554 added a bimorphic inline path but didn't take into account the frequency of the guarding test. This ends up treating both sides of the if as equally frequent which can lead to over inlining and overflowing the method inlining limits. The fix is to grab the frequency from the If and apply that to the branches. This addresses a major source of overinlining that can result in bad performance with JSR 292. We may do a later extension to this to actually do per call chain profiling of selectAlternative but that's a more complicated fix. I also fixed a problem with the ideal graph printer where debugorig printing would go into an infinite loop. Tested with jruby and vm.mlvm tests.

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