Troubles with Shenandoah

[Roman Kennke]

Can you try with -XX:ShenandoahParallelSafepointThreads=2 ? It defaults
to 4, and this seems to cause troubles for yet-unknown reasons.

With this setting, it can handle approximately as much load as other
GCs here. The dropping of messages seems to happen with any GC if load
is high enough, is that correct?

Roman

> Hi,
> 
> On Mon, Apr 8, 2019 at 11:13 AM Roman Kennke <rkennke at redhat.com>
> wrote:
> > I'm still failing to reproduce the problem. I am running with those
> > settings:
> > 
> >           <executable>/home/rkennke/progs/jdk-
> > 12+33/bin/java</executable>
> >           <arguments>
> >             <argument>-showversion</argument>
> >             <argument>-Xmx16g</argument>
> >             <argument>-Xms2g</argument>
> >             <argument>-Xlog:gc:stderr:time,level,tags</argument>
> >             <argument>-XX:+PrintCommandLineFlags</argument>
> >             <argument>-XX:+UnlockExperimentalVMOptions</argument>
> >             <argument>-XX:+UseShenandoahGC</argument>
> > 
> > 
> > and I don't get lost messages or anything like that.
> > 
> > I am having troubles with the benchmark though: if I understand it
> > correctly, the server and client are asking some parameters on
> > startup.
> > However, for some reason, I don't see the messages printed out, but
> > apparently it is waiting for input. So I keep pressing ENTER a
> > couple
> > of times, blindly.
> 
> Please see my previous message about this: it's a Maven library bug
> and I explain the workaround.
> 
> For short runs such as ~10s when you press all enters to the
> benchmark, I also don't see any problem.
> They start to appear for longer runs.
> Try to set batch size = 10000 (i.e. 10 times the default). This will
> make the benchmark run for ~100s and for me this was enough to get
> the
> failures.
> 
> > The questions start appearing then. (Missing
> > terminal flushes/syncs?) Also, the client appears to be waiting for
> > something between test runs. Is there a way to automate this? I.e.
> > pass
> > the parameters to the pom.xml and make the client not wait between
> > runs?
> 
> You can't make automatic back to back runs, but you can tune the
> parameters to make a run longer, see above.
>