[8u] RFR 8250928: JFR: Improve hash algorithm for stack traces

[Jaroslav Bachorík]

Gentle ping?

On Fri, Sep 4, 2020 at 12:35 PM Jaroslav Bachorík
<jaroslav.bachorik at datadoghq.com> wrote:
>
> Now, when https://bugs.openjdk.java.net/browse/JDK-8252754 has been
> fixed I think we can move on with this backport.
>
> Any objections?
>
> Cheers,
>
> -JB-
>
> On Tue, Sep 1, 2020 at 12:01 PM Aleksey Shipilev <shade at redhat.com> wrote:
> >
> > On 9/1/20 11:56 AM, Aleksey Shipilev wrote:
> > > On 8/31/20 7:11 PM, Jaroslav Bachorík wrote:
> > >> Please, review this backport of a hash-collision reducing fix in JFR
> > >> stacktrace values from the main line.
> > >>
> > >> JIRA: https://bugs.openjdk.java.net/browse/JDK-8250928
> > >> Webrev: http://cr.openjdk.java.net/~jbachorik/8250928/8u/webrev/
> > >
> > > 8u backport looks fine.
> >
> > Oh wait, hold on a sec.
> >
> > The original changeset [1] only changes the bit in JfrStackTrace::record_safe. Why does this
> > backport change JfrStackTrace::record_safe and JfrStackTrace::record_thread?
> >
> > --
> > Thanks,
> > -Aleksey
> >
> > [1]
> > https://hg.openjdk.java.net/jdk/jdk/file/c3cc9ac0ede2/src/hotspot/share/jfr/recorder/stacktrace/jfrStackTrace.cpp
> >