RFR: Excluding a few default packages with StackProfiler

[Aleksey Shipilev]

Hi Behrooz,

On 01/23/2015 12:37 PM, Behrooz Nobakht wrote:
> During benchmarking and playing with StackProfile,
> I really needed to be able to exclude certain default
> JVM packages from the stacks.

I understand the use case. However, quite some people use JMH to
identify problems with the JDK itself. So, this new behavior should be
turned off by default.

I also think the filtering by stack head biases the profile a lot. Think
about e.g. the user method that calls into HashMap. It seems odd to
filter out that stack ending in HashMap.get() -- it would miss the
"legitimate" part of a stack. If anything, it should probably filter the
excluded classes from the stack top, but still record it the rest of the
stack as legitimate.

> The result is attached as a patch. I hope that it can be
> reviewed and applied as it may be useful for others, too.

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as required by OpenJDK contribution policy:
 http://openjdk.java.net/contribute/

Thanks,
-Aleksey.