I decided to benchmark JVM startup again, in case of any doubt, and because I see plenty of FUD on this issue.
Code is here: https://github.com/mikera/miscellania/blob/master/src/main/java/hello/world/App.java timecmd bat file use to benchmark is in this SO answer: http://stackoverflow.com/a/6209392/214010 C:\xxx> java -version java version "1.7.0_11" Java(TM) SE Runtime Environment (build 1.7.0_11-b21) Java HotSpot(TM) 64-Bit Server VM (build 23.6-b04, mixed mode) C:\xxx> timecmd java -cp miscellania.jar hello.world.App Hello World! command took 0:0:0.10 (0.10s total) As you can see JVM startup is 0.1s or less: in fact the entire execution of Hello World took 0.1 sec on my machine. Note that this is the server VM. I did about 20 successive runs which were all in the 0.08 to 0.12 sec range. On Friday, 29 March 2013 17:02:34 UTC+8, John Szakmeister wrote: > On Thu, Mar 28, 2013 at 9:26 PM, Mikera <mike.r.an...@gmail.com<javascript:>> > wrote: > > On Friday, 29 March 2013 05:45:53 UTC+8, Laurent PETIT wrote: > >> > >> 2013/3/28 Marko Topolnik <marko.t...@gmail.com>: > >> > 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 certainly don't see that. I've measured this more than a few times, > and it's several seconds for a simple "Hello World" Java application > on any machine that I can touch. Additionally, on an embedded system, > I'm not going to have the same kind of CPU power. For instance, the > current processor we use runs at 400MHz instead of your desktop's > 3GHz. > I suggest you recheck your measurement approach / configuration. See above :-) Agreed that any embedded processor is likely much slower than a PC (mine is a laptop in fact). And IO speed probably makes a big difference as well if there are caching effects / large .jar files to load. > > [snip] > > 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. > > You could argue the same for any application written in C, though I > think in practice C keeps up pretty well. However, raw execution > speed isn't necessarily my goal. More interesting to me is having > better tools to use. Clojure's approach to concurrent programming is > world's better that the "share everything" approach used in C, and > it's that facility that I'd like to use the most. But requiring the > JVM to use it--in my environment--is just too high of a price to pay. > To be honest, LLVM might be too high as well. LLVM is certainly far > from small and lightweight. :-) > Agreed - the JVM is a poor fit for very tightly constrained environments. Excited to see what you can achieve here! Just don't knock the JVM unfairly, it is one of the best tools we have :-) -- -- 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.
