Thank you very much, JC, for looking into this.
http://mail.openjdk.java.net/pipermail/zgc-dev/2018-August/000455.html
The link above provides an explanation of why it is difficult to support
ZGC with SA where there is an iteration over the heap. And currently, I
am unsure as to whether we will devise a way to overcome this issue. We
currently have the following JBS entry for tracking this.
https://bugs.openjdk.java.net/browse/JDK-8207843 (SA: Add support for
Object Histogram with ZGC)
I have added a comment in the ER above to keep track of enabling the
tests if this is resolved.
I agree with your comment on throwing a RuntimeException. Doing this
avoids the misleading "heap written to" message. I will modify this and
remove the ';' you pointed out and post another webrev.
Thank you,
Jini.
On 11/9/2018 9:36 PM, JC Beyler wrote:
Hi Jini,
The webrev looks good to me as well except for a few questions/comments:
I have a generic question that is related to the webrev:
- Are there plans at some point for Jmap to support ZGC heaps in the
future ? Or is this infeasible?
I ask because if a lot of tests are disabled for ZGC for a
limited amount of time (in order to provide time for future support)
there should be a means to scrub the tests at a later date to see which
are now supported, no?
- In
http://cr.openjdk.java.net/~jgeorge/8213323/webrev.00/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/utilities/HeapHprofBinWriter.java.html:
397 if (vm.getUniverse().heap() instanceof ZCollectedHeap) {
398 System.err.println("WARNING: Operation not supported
for ZGC.");
399 return;
400 };
- 1 nit is the ';' after the closing '}'
- Should the code throw a RuntimeException instead? Just printing
an error seems "weak" for me when this really won't work. Of course,
that means tracking the callers now of write and probably adding
exception handling there and I'm not sure that is something that is
warranted here but thought I would ask :)
Thanks!
Jc
Thanks,
Jc
On Fri, Nov 9, 2018 at 1:47 AM gary.ad...@oracle.com
<mailto:gary.ad...@oracle.com> <gary.ad...@oracle.com
<mailto:gary.ad...@oracle.com>> wrote:
Looks OK to me.
On 11/9/18 1:40 AM, Jini George wrote:
> Hello!
>
> Requesting reviews for a small change for disabling the testing of
> TestJmapCoreMetaspace.java and TestJmapCore.java with ZGC. The
change
> also includes skipping of creating the heapdump file with jmap if
the
> GC being used is ZGC.
>
> Webrev: http://cr.openjdk.java.net/~jgeorge/8213323/webrev.00/
> Bug ID: https://bugs.openjdk.java.net/browse/JDK-8213323
>
> Thanks,
> Jini.
--
Thanks,
Jc
