Yes with branch netty-4.1.3.Final > Le 22 Jul 2016 à 09:21, 'Norman Maurer' via Netty discussions > <[email protected]> a écrit : > > Yes this sounds not right… So what are the steps to reproduce ? Fire up a vm, > checkout vert.x master and run the build ? > > >> On 22 Jul 2016, at 00:51, Julien Viet <[email protected]> wrote: >> >> Hi, >> >> we are seing OOM "GC overhead limit exceeded" issue in Vert.x test suite on >> slow machines like Cloudbees or using virtualization on a laptop. >> >> This issue means that the VM spend more time in GC than the rest of the VM >> (98%), but I’m pretty sure everyone here knows that already. >> >> In the case of Vert.x testsuite, it happens because we create and destroy >> many Vertx instances and therefore many event loops / threads during the >> tests. >> >> I spent quite some time on the issue and I found that it happens because the >> ThreadDeatchWatcher's Recycler DELAYED_RECYCLE fast thread local is a >> WeakHashMap<Stack, WeakOrderQueue) used by the ThreadPoolCache grows and >> retains many entries (up to 2000). This WeakHashMap contains recycled >> objects with large footprint and also the Stack itself reference its Thread >> that has a large footprint. >> >> I am not saying it is a leak per se, but the maps grows and takes time to be >> garbaged. This does not prevent the testsuite to run on a laptop but it >> slows it down and on a slow machines it prevents running the testsuite >> entirely. >> >> I believe this behavior was introduced by this commit : >> https://github.com/netty/netty/commit/afafadd3d7caf1e4b346da049baab0afeae0a4bc >> >> The change that makes the whole difference is : >> https://github.com/netty/netty/commit/afafadd3d7caf1e4b346da049baab0afeae0a4bc#diff-23eafd00fcd66829f8cce343b26c236aR226 >> >> The introduction of the field stack in the WeakOrderQueue keeps a reference >> on the Stack objects, however Stack instances are also weak keys of the fast >> thread local WeakHashMap and therefore defeats the purpose of the >> WeakHashMap. Not entirely as it is GC’ed but much less often and increase >> the memory footprint. >> >> let me know what you think >> >> Julien >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Netty discussions" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/netty/2A547499-D279-4286-AA95-3447EE2B621E%40julienviet.com. >> For more options, visit https://groups.google.com/d/optout. > > -- > You received this message because you are subscribed to the Google Groups > "Netty discussions" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/netty/D5C167E1-D3C3-4B8F-B4B8-FD4D1793BC1F%40googlemail.com. > For more options, visit https://groups.google.com/d/optout.
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