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

[Dmitry Fazunenko]

Hi Igor,

thanks for such a prompt response.

-- Dima

On 09.01.2017 16:57, Igor Ignatyev wrote:
> Hi Dima,
>
> the fix looks good to me, thank you.
>
> — Igor
>> On Jan 9, 2017, at 4:50 PM, Dmitry Fazunenko <dmitry.fazunenko at oracle.com> 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
>>
>>
>>