On Fri, 23 Jun 2023 21:24:20 GMT, Vladimir Ivanov <vliva...@openjdk.org> wrote:
>> @iwanowww - I'm confused by what a "Diagnostic" flag is. According to [this >> documentation](https://wiki.openjdk.org/display/HotSpot/Hotspot+Command-line+Flags%3A+Kinds%2C+Lifecycle+and+the+CSR+Process) >> "Diagnostic flags are not meant for VM tuning or for product modes. They >> are to be used for VM quality assurance or field diagnosis of VM bugs [...]" >> I believe the patch I'm proposing is a VM tuning optimization, so should it >> really be a diagnostic flag? Besides, I think we'll try _at a later moment_ >> to make this a product flag. Do you think an experimental flag is more >> appropriate? Thank you. > > You can look at it in the following way: since the flag is set to true by > default, the feature is unconditionally available in product binaries. The > only reason to explicitly specify the flag is to turn the optimization off > and it may be needed to diagnose VM crashes or performance regressions. > > As an afterthrought, maybe C2 should check a compiler directive (and not a > global flag) to be able to control the optimization up to per-method > granularity. Thank you @iwanowww for clarifying. Now I understand this better. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/12897#discussion_r1244190081
