C2 compiler hangs and eats memory in escape analysis

Vladimir Kozlov vladimir.kozlov at oracle.com
Fri Jan 23 23:57:55 UTC 2015

On 1/23/15 3:41 PM, Fredrik Tolf wrote:
> On Thu, 22 Jan 2015, Vladimir Kozlov wrote:
>> It is also https://bugs.openjdk.java.net/browse/JDK-8041984
>> Both bugs are fixed in jdk 8u40 too.
>> Fredrik, you can download early access 8u40 and try it:
>> https://jdk8.java.net/download.html
> Ah, thank you and sorry for not checking the EA in advance. It does
> indeed catch the problem I'm seeing.

Did it catch or solve your problem?

> However, judging from the description ("[...] in a very rare situation")
> of the linked bug report and the nature of the solution (a timeout if
> the CG phase takes too long), it seems to me that this might be a
> workaround to a problem that you might not have been able to reproduce
> reliably enough to find any root cause. Correct me if I'm wrong, of course.

No, I reproduced it reliable with GraphHopper program as I reported in 
8041984. The data connection graph is way too complex and it take a lot 
of time to build (about 20000 nodes in graph). I did not find a solution 
other than to check time on each build's iteration and bailout. I 
understand that the algorithm used to build the graph may be not optimal 
but we don't have resources to work on it now.

> If that is the case, I do indeed have a close to perfectly reproducible
> test-case over here, so if you want me to produce information for you to
> find the actual root cause, I'd be happy to do so.

Yes, it would be nice if you can provide a simple (small number of 
nodes) test which we can run. It may help to identify particular parts 
in code which we can improve.


> --
> Fredrik Tolf

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