RFR: 8277893: Arraycopy stress tests

[Vladimir Kozlov]

On Tue, 30 Nov 2021 20:21:19 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> test/hotspot/jtreg/compiler/arraycopy/stress/AbstractStressArrayCopy.java line 32:
>> 
>>> 30:      * Max array size to test.
>>> 31:      */
>>> 32:     static final int MAX_SIZE = 1024*1024 + 1;
>> 
>> Do we really need such big arrays for regression testing. It may make sense for JMH but not for these tests I think.
>
> My original intent was to make sure the tests cross all small page sizes (up to 64K) and maybe even some large page sizes (1M `long[]` is 8M, so 2*4M). The size of this array does not matter for test performance very much, since we only allocate two `MAX_SIZE`-d arrays per entire run. Driver even caps the heap size at `-Xmx256m` to block tests from using too much memory. So, I'd leave it at 1M, if you agree.

Okay. I was concern because of times you show. I am fine with running tests upto 10-15 mins but not this:

# x86_64 (i5-11500)
  real    41m32.622s
  user    447m19.986s
  sys     0m21.026s


Do you know why it takes so much time on it?

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PR: https://git.openjdk.java.net/jdk/pull/6594