RFR(S): 8237375: SimpleThresholdPolicy misses CounterDecay timestamp initialization

[Doerr, Martin]

Hi Volker,

thanks for the review!

Best regards,
Martin


> -----Original Message-----
> From: Volker Simonis <volker.simonis at gmail.com>
> Sent: Montag, 20. Januar 2020 18:58
> To: Doerr, Martin <martin.doerr at sap.com>
> Cc: hotspot-compiler-dev at openjdk.java.net; David Holmes
> (david.holmes at oracle.com) <david.holmes at oracle.com>
> Subject: Re: RFR(S): 8237375: SimpleThresholdPolicy misses CounterDecay
> timestamp initialization
> 
> Looks good to me.
> 
> Thanks,
> Volker
> 
> On Mon, Jan 20, 2020 at 6:26 AM Doerr, Martin <martin.doerr at sap.com>
> wrote:
> >
> > Hi,
> >
> > I'd like to fix warmup issues we observed in test
> compiler/c2/Test8004741.java.
> > The issue is a missing timestamp initialization which leads to a premature
> counter decay at the first safepoint with -XX:-TieredCompilation.
> >
> > Bug:
> > https://bugs.openjdk.java.net/browse/JDK-8237375
> >
> > Webrev:
> > http://cr.openjdk.java.net/~mdoerr/8237375_CounterDecay/webrev.00/
> > The webrev applies on top of the preliminary fix for
> https://bugs.openjdk.java.net/browse/JDK-8235741.
> > I'll wait until that one gets pushed.
> >
> > What it changes:
> >
> >   *   Move class CounterDecay up
> >   *   Introduce reset_last_timestamp()
> >   *   Use this function in decay() and in SimpleCompPolicy::initialize()
> >
> > Best regards,
> > Martin
> >