RFR(XS): 8198510: Limit GC threads for small Java heap

Stefan Johansson stefan.johansson at oracle.com
Thu Feb 22 13:13:58 UTC 2018

On 2018-02-22 11:32, Thomas Schatzl wrote:
> Hi,
> On Wed, 2018-02-21 at 16:17 +0000, Doerr, Martin wrote:
>> Hi Thomas,
>> thanks for discussing this topic with your colleagues.
>> I have a webrev which simply switches on UseDynamicNumberOfGCThreads
>> by default:
>> http://cr.openjdk.java.net/~mdoerr/8198510_gc_threads/webrev.01/
>> I'll test it in our nightly tests. If I get approval from 2 reviewers
>> and no objections, I'll push it to the submission forest and later to
>> jdk/hs.
>    - the description of the flag mentions Parallel GC explicitly - this
> functionality is available in all (parallel) collectors.
> Something like:
> "Dynamically choose the number of threads up to a maximum of
> ParallelGCThreads parallel collectors will use for garbage collection
> work"
>    - I just started a run in our test system with that change. Let's see
>   if and what fails due to that.
>    - unfortunately this is a public interface change, so we need to wait
> for the CSR to be approved I filed for you, JDK-8198547.
> I filled in all parts except for the specification - it would be nice
> to be able to put the inline diff there (since it's so small) and link
> the final webrev and a comment containing a reference to this the mail
> thread.
> I will add (an internal) link to test results when it finishes
> hopefully without any new issues.
> When all this is done, we need at least one Reviewer (me and maybe
> somebody else) to review the CSR and add themselves to the "Reviewed-
> by" field (Use the "Edit" button on the top left) so that we can fast-
> track it, ie. set it to "Finalized" and then wait for comment from the
> CSR approval board :)
I can review it, but first the missing specification needs to be added 
and then it should be moved to "Proposed" state.

> Thanks,
>    Thomas

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