Fwd: RFR (XXS): 8169643: [TESTBUG] GCBasher test fails with G1, CMS and Serial.
thomas.schatzl at oracle.com
Tue Jan 10 19:58:21 UTC 2017
On Tue, 2017-01-10 at 19:09 +0300, Dmitry Fazunenko wrote:
> Hi Thomas,
> On 09.01.2017 17:38, Thomas Schatzl wrote:
> > Hi,
> > On Mon, 2017-01-09 at 16:50 +0300, Dmitry Fazunenko wrote:
> > >
> > > Hi in the new year!
> > >
> > > I got off line comment from Igor I. that Xmx is not needed here
> > > at
> > > all.
> > > And I agree with Igor.
> > > GCBasher test was written many years ago, probably in those times
> > > when default maximum heap size was 64MB.
> > > So, specifying Xmx was necessary to increase heap to allocate
> > > such a
> > > big structure.
> > > Nowadays, it's hard to find a host where maximum heap size set by
> > > the
> > > ergonomics will be less than 256MB.
> > > GCBasher doesn't try to allocate all available memory, it just
> > > allocates a big structure several time.
> > > So, I think -Xmx option could be removed from this test:
> > >
> > > http://cr.openjdk.java.net/~dfazunen/8169643/webrev.02/
> > >
> > > Tested by RBT with and without -XX:-UseCompressedOpps
> > >
> > I think the limitation has been introduced so that gcbasher does
> > something useful, i.e. execute enough GCs. With a multi-GB heap at
> > its
> > disposal, I expect that the amount of GCs executed will be
> > significantly lower than it is now.
> Your arguments do certainly make sense.
> > I prefer to have a 256M limit to none; and maybe the test could be
> > run
> > once with and without UseCompressedOops with appropriate heap sizes
> > instead if there is enough cpu time in our testing infrastructure.
> I suggest to start with original version of the fix:
> (+ copyright updates)
> and submit an RFE to limit max heap size depending of
> Such RFE could implemented much easily after integration of
> JDK-8172417 Verundy: Library to simplify using TestNG for
> Hotspot test development
> Now it's a bit tricky to get known from the test the values of
> external tags.
> Are you okay with that?
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