[jira] [Comment Edited] (SLING-6756) Remove setting/advising to set permsize and max heap size

["Konrad Windszus (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/SLING-6756?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15949038#comment-15949038 ] 

Konrad Windszus edited comment on SLING-6756 at 3/30/17 1:27 PM:
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The {{jvm.config}} file is a catch-all measure which ensures that we don't get build failures or indeed slow builds due to incorrect JVM arguments.

The ant-based checks were removed in SLING-5862 because with Maven 3.3.9 the {{jvm.config}} file is supported, so the build will get the correct JVM arguments.

Once we move to Java 8+ it makes perfect sense to remove the PermGen settings. I am not sure about the max heap size setting though, I think that is still valuable, for instance when building on small vms, which can happen on Jenkins.


was (Author: rombert):
The {{jvm.config}} file is a catch-all measure which ensures that we don't get build failures or indeed slow builds due to incorrect JVM arguments.

The ant-based checks were removed in SLING-586 because with Maven 3.3.9 the {{jvm.config}} file is supported, so the build will get the correct JVM arguments.

Once we move to Java 8+ it makes perfect sense to remove the PermGen settings. I am not sure about the max heap size setting though, I think that is still valuable, for instance when building on small vms, which can happen on Jenkins.

> Remove setting/advising to set permsize and max heap size
> ---------------------------------------------------------
>
>                 Key: SLING-6756
>                 URL: https://issues.apache.org/jira/browse/SLING-6756
>             Project: Sling
>          Issue Type: Improvement
>            Reporter: Konrad Windszus
>
> PermSize is no longer an issue with java 8 as Java 8 no longer knows a dedicated permgen space (https://dzone.com/articles/java-8-permgen-metaspace). Still we set {{-XX:MaxPermSize=256m}} in https://github.com/apache/sling/blob/trunk/.mvn/jvm.config (SLING-4530) which leads to a warning when building with Java 8.
> The related ant check in parent has been removed though in https://issues.apache.org/jira/browse/SLING-5862. Althought the reason why the check has been removed is a bit unclear to me from the comments, I would propose to remove the jvm.config completely and do no longer advise to set permsize or heapsize explicitly.
> The heapsize is currently bound to at most 512MB, which is in 90% of the cases just limiting the maximum heapsize of a modern JVM (because it should be 1/4 of the physical memory in most of the JVM, see http://stackoverflow.com/questions/4667483/how-is-the-default-java-heap-size-determined).



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