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

[Doerr, Martin]

Hi David,

I'll change it to update_last_timestamp before pushing.
Can I add you as reviewer?

Best regards,
Martin


> -----Original Message-----
> From: David Holmes <david.holmes at oracle.com>
> Sent: Montag, 20. Januar 2020 22:54
> To: Doerr, Martin <martin.doerr at sap.com>; 'hotspot-compiler-
> dev at openjdk.java.net' <hotspot-compiler-dev at openjdk.java.net>
> Cc: David Holmes <David.Holmes at oracle.com>
> Subject: Re: RFR(S): 8237375: SimpleThresholdPolicy misses CounterDecay
> timestamp initialization
> 
> Hi Martin,
> 
> On 21/01/2020 12:25 am, Doerr, Martin 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()
> 
> "reset" suggests clearing or moving back to an original value to me. How
> about just "set" or "update"?
> 
> Cheers,
> David
> 
> >   * Use this function in decay() and in SimpleCompPolicy::initialize()
> >
> > Best regards,
> >
> > Martin
> >