RFR(S): 8202169: Reduce ctw_2 duration by parallelizing CtwRunner invocations

[Vladimir Kozlov]

Looks good.

Ask Igor Ignatyev to look as author of code.

Thanks,
Vladimir

On 4/23/18 6:58 PM, Mikael Vidstedt wrote:
> 
> Please review this change which parallelizes the 
> CompileTheWorld/CtwRunner invocations to reduce the (wall clock) 
> duration of running the ctw_2 jtreg test group.
> 
> bug: https://bugs.openjdk.java.net/browse/JDK-8202169
> webrev: 
> http://cr.openjdk.java.net/~mikael/webrevs/8202169/webrev.00/open/webrev/
> 
> The CompileTheWorld class already has support for specifying the start 
> and end class (index), so this change just enables passing the relevant 
> arguments in to the CtwRunner wrapper class. For flexibility I made it 
> possible both to specify the start/stop values both as absolute index, 
> or as percentage values. This change only uses the latter format.
> 
> Cheers,
> Mikael
>