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 ----- Mail original ----- > 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 seconds or more. Sometimes > > > > > the > > > > > servers will recover, sometimes they require a restart of the > > > > > webserver > > > > > (spring boot/tomcat). When the applications slow down we always see > > > > > the > > > > > tomcat thread pool hit the maximum size. Every single thread in the > > > > > thread > > > > > pool is in the RUNNABLE state but appears to be making no progress. > > > > > Successive thread dumps show that the stacks are changing, but VERY > > > > > slowly. > > > > > The top of the stack is always this method: > > > > > > > > > > > > > > > at > > > > > java.lang.invoke.MethodHandleNatives.setCallSiteTargetNormal(Native > > > > > Method). > > > > > > > > > > > > > > > The other common condition is that whatever application code is on > > > > > the > > > > > stack > > > > > is always dynamically compiled. Code that is @CompileStatic is NEVER > > > > > on > > > > > the > > > > > stack when we see these slowdowns. > > > > > > > > > > > > > > > The thread dumps showed that the application code is never waiting on > > > > > locks, > > > > > socket reads, db connections, etc. > > > > > > > > > > > > > > Mabye worth mentioning, that with @CompileStatic annotated code is not > > > > using > > > > invokedynamic.... > > > > > > > > > > Anyway... I am wondering if anyone has had something like this before. > > > > My > > > > first reaction to this description would be a bug in the JVM... or a > > > > performance bottleneck in the JVM.... but to spend literally seconds in > > > > native code is pretty bad in any case. On the other hand I am not > > > > having > > > > this web application here to experiment with. The only part I did hear > > > > is, > > > > that removing the indy version of Groovy seems to fix the problem. So > > > > it > > > > must be either our use of indy, or indy itself having a problem here. > > > > But > > > > asides from this conclusion I am quite at a loss. > > > > > > > > > > Question 1: Did anyone have a similar problem before? > > > > > > > > > > Question 2: Maybe more to the JVM engineers, is it even possible for > > > > the > > > > indy > > > > part to suddenly tak seconds on compilation - or especially the > > > > mentioned > > > > native method? > > > > > > > > > > bye Jochen > > > > > > > > > > -- > > > > > > > > > > You received this message because you are subscribed to the Google > > > > Groups > > > > "JVM Languages" group. > > > > > > > > > > To unsubscribe from this group and stop receiving emails from it, send > > > > an > > > > email to jvm-languages+unsubscr...@googlegroups.com . > > > > > > > > > > To post to this group, send email to jvm-langua...@googlegroups.com . > > > > > > > > > > Visit this group at https://groups.google.com/group/jvm-languages . > > > > > > > > > > For more options, visit https://groups.google.com/d/optout . > > > > > > > > > -- > > > > > > You received this message because you are subscribed to the Google Groups > > > "JVM Languages" group. > > > > > > To unsubscribe from this group and stop receiving emails from it, send an > > > email to jvm-languages+unsubscr...@googlegroups.com . > > > > > > To post to this group, send email to jvm-langua...@googlegroups.com . > > > > > > Visit this group at https://groups.google.com/group/jvm-languages . > > > > > > For more options, visit https://groups.google.com/d/optout . > > > > > -- > > > You received this message because you are subscribed to the Google Groups > > "JVM Languages" group. > > > To unsubscribe from this group and stop receiving emails from it, send an > > email to jvm-languages+unsubscr...@googlegroups.com . > > > To post to this group, send email to jvm-langua...@googlegroups.com . > > > Visit this group at https://groups.google.com/group/jvm-languages . > > > For more options, visit https://groups.google.com/d/optout . > > -- > You received this message because you are subscribed to the Google Groups > "JVM Languages" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to jvm-languages+unsubscr...@googlegroups.com . > To post to this group, send email to jvm-langua...@googlegroups.com . > Visit this group at https://groups.google.com/group/jvm-languages . > For more options, visit https://groups.google.com/d/optout .
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