[External] : Re: ReplayCompiles as non-develop switch ?

[Thomas Stüfe]

Thanks a lot Vladimir!

On Wed, Aug 17, 2022 at 8:04 PM Vladimir Kozlov <vladimir.kozlov at oracle.com>
wrote:

> On 8/16/22 9:01 PM, Thomas Stüfe wrote:
> > On Tue, Aug 16, 2022 at 9:00 PM Vladimir Kozlov <
> vladimir.kozlov at oracle.com <mailto:vladimir.kozlov at oracle.com>> wrote:
> >
> >     On 8/16/22 10:05 AM, Thomas Stüfe wrote:
> >      > Hi,
> >      >
> >      > Is there a particular reason why ReplayCompiles needs to be a
> develop switch? Or was it just not considered useful
> >      > without asserts?
> >
> >     It replays compilation which we want to debug in debug VM. Why do
> you want it be `product` flag?
> >
> >     We have DumpReplayDataOnError product flag to dump compiler replay
> data from product VM:
> >
> https://github.com/openjdk/jdk/blob/master/src/hotspot/share/compiler/compiler_globals.hpp#L331
> >     <
> https://urldefense.com/v3/__https://github.com/openjdk/jdk/blob/master/src/hotspot/share/compiler/compiler_globals.hpp*L331__;Iw!!ACWV5N9M2RV99hQ!JRgjhoZKOMvpjeekz0FN5_oc8OR6PZp-lDqLr7W_AEpu5wV0xtVtbCvvgD_XWCIeoqN88QPk0i9nNBU6w2OexzZiW4G-$
> >
> >
> >
> > Hi Vladimir,
> >
> > to reproduce a compiler error in a release VM.
> >
> > - to experiment what its effect is on a VM that was actually shipped to
> customers, without using a debug VM and
> > switching tens of asserts off. E.g., in the case of
> https://bugs.openjdk.org/browse/JDK-8291665
> > <https://bugs.openjdk.org/browse/JDK-8291665>, how steep and how
> quickly RSS raises, and whether the raise limits itself
> > or is infinite.
> > - to see whether a certain build of a shipped VM is actually affected by
> a certain bug. Not every bug surfaces in every
> > build.
> >
> > None of that are very hard reasons, and these situations are rare. But
> they do occur, and it would be a bit more
> > convenient to have this switch.
>
> So you want it for verification purpose and not for debugging an issue. We
> did not consider it when implemented.
> I agree it could be useful and it is not hard to convert ReplayCompiles to
> diagnostic flag.
> It will increase VM size but not much.
>
> File RFE.
>
> Thanks,
> Vladimir K
>
> >
> > Cheers, Thomas
> >
> >
>
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