RFR(M) 8227003: Add high-level JIT compilation mode control mechanism

[Igor Veresov]

> On Oct 14, 2019, at 3:19 AM, Claes Redestad <claes.redestad at oracle.com> wrote:
> 
> 
> On 2019-10-13 18:51, Igor Veresov wrote:
>>  Ok, I followed the notation you proposed, here’s the webrev: http://cr.openjdk.java.net/~iveresov/8227003/webrev.01/
> 
> Thanks for picking up the proposal! :-)
> 
> Some comments:
> 
> - For the sake of completeness the default value should be explicit,
>   i.e., tiered or default, and not NULL. Default flag values show up
>   when running -XX:PrintFlagsFinal and such, so it's good with
>   unsurprising output.

Sure.

> 
> - src/hotspot/share/runtime/globals.hpp:
> 
>   "TieredMode=4" in comments a number of times, should be something
>   like "CompilationMode=highOnly|highOnlyQuickInternal"?
> 

Right, thanks, I’ll fix this.

Webrev: http://cr.openjdk.java.net/~iveresov/8227003/webrev.02/

> - Since we're adding flags then I think a CSR is needed. My suggestion
>   is to change subject to something like "Add high-level JIT
>   compilation mode control mechanism".

I don’t think we need a CSR, we’re only adding flags. Everything stay backwards-compatible.

Igor

> 
> Thanks!
> 
> /Claes