Ping: RFR: JDK-8205523: Explicit barriers for interpreter

Andrew Haley aph at
Fri Jun 29 12:59:56 UTC 2018


On 06/27/2018 12:13 PM, Erik Österlund wrote:

> I am a fan of profile guided optimization. I would definitely not mind 
> introducing these concepts in the compilers where they are with no doubt 
> necessary (and we also have the right tools for dealing with this 
> better). In fact, they already have read/write decorators that could be 
> used for resolve barriers in our compilers, and can use algorithms to 
> safely elide barriers where provably correct, so it makes perfect sense 
> for me to use such concepts there.
> I'm just not sure that the interpreter needs to be polluted with this 
> conceptual overhead, unless there is at least one benchmark that can 
> show that we are solving an actual problem with this. Remember, 
> premature optimizations are the root of all evil.

but efficient systems are made from thousands of tiny optimizations, each
one too small to be measured above the noise on its own.

Andrew Haley
Java Platform Lead Engineer
Red Hat UK Ltd. <>
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