On Friday, 29 March 2013 05:45:53 UTC+8, Laurent PETIT wrote: > 2013/3/28 Marko Topolnik <marko.t...@gmail.com <javascript:>>: > > Or you may have just a trivial requirement for a program that both > starts > > and executes quickly. > > To what extent would an LLVM / C version of a Clojure program not > incur startup penalty as the JVM does. > > As far as I understand it, the startup cost is manyfold: > 1/ JVM startup > 2/ loading of Clojure Core > 3/ loading of non-lazy parts of your application (generally from > loading a global namespace to invoke its -main function) >
In my experience 1) is a small fraction of the total. A trivial "hello world" Java program runs in less than 0.1sec on my machine, which proves that JVM startup isn't really important. Or at least, far less important than most people think. > > I know AOT compilation can somehow reduce load-time of 2/ and 3/, but > not bring them to zero. As far as I understand it, all the namespaces > involved in your application will still have to be linearly executed, > in a depth-first manner following the graph of namespace dependencies > + loaded configuration files etc. Only the compilations of functions > will be optimized into loading of their corresponding classes. > > So, short of having a "image-like" environment, I wonder what the time > taken to do 2/ + 3/ would be in LLVM / C versions of Clojure. > It might even be slower in LLVM / C, unless you can at least match the JVM in terms of JIT optimisation and garbage collector efficiency, which in turn affects the runtime for 2+3 (I believe a garbage collector is a requirement to execute Clojure?). Beating the JVM isn't an easy feat. Something I would be very interested in would be enhancements to Clojure that allow for lazy compilation, i.e. deferring compilation of parts of your application or Clojure Core until they are directly invoked for the first time. This is probably going to be the most promising approach for reducing Clojure startup time, although I expect it would require some breaking changes. -- -- 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/groups/opt_out.
