Hi,
I did run into this issue with Nashorn as well. That was back in 2013, but
a certain Nick Houghton (cc, who will be glad to here there’s finally a bug
filed) contacted me about that in Dec'15, asking whether I had made any
progress, because he had discovered the same issue.
Here’s my original thread:
http://mail.openjdk.java.net/pipermail/mlvm-dev/2013-September/005489.html
Maybe Jochen or Remi will still remember.
Anyways, I think we did solve this issue by eliminating a pattern where we
would globally define objects in our script environment via calls to
NashornScriptEngine.put. I suspect that overriding the same global variable
repeatedly and hence, I suppose, invalidating corresponding call sites,
might’ve triggered the pathologic behaviour.
Just wanted to let you know, in case it help narrowing down the issue /
understanding the impact.
Kind Regards,
Benjamin
On 16 March 2016 at 12:41, Remi Forax <fo...@univ-mlv.fr> wrote:
> The symptoms are really like a deoptimization storm,
> setCallSiteTargetNormal goes to a safepoint (which is worst that only
> having the compiler/JIT lock because all threads are stopped),
> when either a code calls setTarget or a SwithPoint is invalidated.
>
> You have a deopt storm when the JIT compiles a code that contains a
> callsite that is always invalid, so the VM enters in loop like this,
> JIT compile a blob
> execute the blob
> deopt
> jump back in the interpreter
> rinse and repeat
>
> The root cause is a bug in the invalidation logic of the language runtime
> (not the VM) but it's hard to spot without a reproducible test case because
> when the JIT compiles a blob of codes there are several callsites inside
> that blob and usually only one is the faulty one.
>
> We already have discussed about that point several times,
> John is a proponent of marking the callsite has should never be optimized
> again,
> which at least stop the storm issue but it sweeps the real cause of the
> bug under carpet,
> I would prefer, consider these kind of bugs as a language runtime bugs
> that should be investigated by the runtime developers.
>
> Perhaps a middle ground is to mark the callsite as not compilable anymore
> *and* emit a warning (like when the code cache is full) to not hide the
> root cause of the bug.
>
> Rémi
>
> --
>
> *De: *"Hannes Wallnöfer" <hann...@gmail.com>
> *À: *jvm-langua...@googlegroups.com
> *Envoyé: *Mercredi 16 Mars 2016 11:52:42
> *Objet: *Re: [jvm-l] slow downs in invokedynamic native code
>
> I've filed a bug for this:
>
> https://bugs.openjdk.java.net/browse/JDK-8151981
>
> For the Nashorn report, the only thing we know is that it involves pretty
> large scripts that are being re-evaluated in new ScriptEngines, with 8
> engines at a time. So it seems quite possible that some implementation
> detail is stressed beyond the point where it performs efficiently.
>
> Hannes
>
>
> 2016-03-16 11:44 GMT+01:00 Duncan MacGregor <duncan.macgre...@gmail.com>:
>
>> I haven't seen this, but setCallSiteTargetNormal does have to get the
>> compiler lock, so contention can definitely cause problems. Is there a
>> chance you're repeatedly invalidating and setting targets? Or generating
>> lots of new mutable call sites?
>>
>> The other possibility is that the data structures that store the target
>> information aren't scaling, but j have seen a big problem there before, and
>> Magik on Java apps tend to be large, so I'd expect to have hit any problems
>> by now.
>>
>> Duncan.
>>
>> On 16 Mar 2016, at 10:28, Hannes Wallnöfer <hann...@gmail.com> wrote:
>>
>> Hi Jochen,
>>
>> we recently had a report on nashorn-dev that could be related. A user is
>> re-evaluating the same or similar code again and seeing more than 20x
>> slowdown compared to the fist evaluation.
>>
>> http://mail.openjdk.java.net/pipermail/nashorn-dev/2016-March/006024.html
>>
>> The thing is that he is using fresh ScriptEngines for the second
>> evaluation, so the Nashorn engines should not share anything. As with your
>> case, Jvisualvm shows that 80% of time is spent in
>> java.lang.invoke.MethodHandleNatives.setCallSiteTargetNormal().
>>
>> Hannes
>>
>>
>> 2016-03-15 10:28 GMT+01:00 Jochen Theodorou <blackd...@gmx.org>:
>>
>>> Hi,
>>>
>>>
>>> One of our users has a web application using Groovy with indy activated
>>> and describes the following problem:
>>>
>>> At random intervals and a random times our web servers will go from
>>>> serving responses in the 300 ms range to taking 30
