Fwd: RFR (XXS): 8169643: [TESTBUG] GCBasher test fails with G1, CMS and Serial.

Michail Chernov michail.chernov at oracle.com
Mon Jan 9 14:06:01 UTC 2017


Hi Dima,

The change looks good to me.

Misha


On 09.01.2017 16:50, 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
>
>
> Thanks,
> Dima
>
>
>
> -------- Forwarded Message --------
> Subject: 	RFR (XXS): 8169643: [TESTBUG] GCBasher test fails with G1, 
> CMS and Serial.
> Date: 	Thu, 29 Dec 2016 17:25:26 +0300
> From: 	Dmitry Fazunenenko <dmitry.fazunenko at oracle.com>
> To: 	hotspot-gc-dev <hotspot-gc-dev at openjdk.java.net>
>
>
>
> Hi everyone,
>
> I'm looking for a couple of review for a simple change in test: -Xmx128m
> -> -Xmx256m
>
> http://cr.openjdk.java.net/~dfazunen/8169643/webrev.00/
> https://bugs.openjdk.java.net/browse/JDK-8169643
>
> The GCBasher test fails with OOM if run with -XX:-UseCompressedOpps.
> The root cause is 128Mb is not enough to locate a big structure if Opps
> are not compressed.
> Giving more memory fixes the problem (TestGCBasherWithParallel.java
> specifies 256m and doesn't fail)
>
> Thanks,
> Dima
>
>

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