Every thread created on the JVM takes about 2MB of memory. Multiply that by that number of threads, and I'm surprised your memory usage is that low. But the futures thread pool will also re-use previously created threads for new futures. In order to optimize this, a certain number of threads will be kept around for some time incase they need to be reused. In my limited testing it takes about a minute for the pool to decide to shutdown the threads.
On top of all that, you're measuring the JVM memory usage through Window's task manager, from what I can tell. Internally the JVM may be using way less memory, but it hasn't bothered to give that back to the OS yet because it guesses that if you used this much memory in the past, you may use that amount again soon. In certain configurations, the JVM may never give the memory back the OS. So if you want accurate memory usage stats you should use a tool that can look into the internals of the JVM, or perhaps use some of the GC stats you can access via the Runtime class. On Tue, Sep 5, 2017 at 2:14 PM, Max Muranov <phot...@gmail.com> wrote: > Hello! I've read in this > <https://groups.google.com/forum/#!topic/clojure/CRStVPHjg8o> thread that > futures are garbage collected and it's okay to use them for side effects. > But what about such program? > > (dotimes [n 100000] > (future (Thread/sleep 1000))) > > After performing the code several times I see this in my task manager: > > > After each performing the amount of using memory increases. So how can I > use futures to free the memory after they were finished? > > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > --- > You received this message because you are subscribed to the Google Groups > "Clojure" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to clojure+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- “One of the main causes of the fall of the Roman Empire was that–lacking zero–they had no way to indicate successful termination of their C programs.” (Robert Firth) -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
