I've written several of the Clojure programs on the site. I'm not omniscient when it comes to writing efficient Clojure code, but I know a few of the techniques. Several, if not most, of the Clojure solutions already take advantage of mutable data structures, for example.
There are some faster programs people have created for a few of the problems, but they haven't been submitted yet, due to lack of time/interest. I might get some of them submitted over the next several weeks. I suspect the average ratio of <Clojure run time> / <Java run time> can be brought closer to the range of x1 through x5 or so, rather than the current range of x2 through x12. It used to be in the range of x1 to x8 or so, but over the last year the Java program submissions have gotten faster while the Clojure ones haven't been improved, or not as much. Getting x1 or even x2 across all problems seems highly unlikely to me, but I'd be happy to be proved wrong. It is true that a few of the problems have very short run times for the Java programs that extra Clojure init time makes it difficult for them to compete (e.g. best Java run times for reverse-complement and fasta-redux problems are under 2 sec), but half of them take over 20 sec to complete using the Java programs, which should give both Java and Clojure programs plenty of time for JIT optimizations to take effect. The remaining differences are either differences in the algorithm or data structure in use, and/or the efficiency of the resulting byte codes from Java and Clojure compilers. As for memory used, "Hello, world" takes about 60 to 70 Mbytes of resident memory to complete, so no Clojure program will be below that. If you want thousands of separate JVMs running Clojure processes, each with a small memory footprint, I wouldn't recommend it, but I doubt anyone would want to do that. It is more fair to compare memory use for problems that require a larger amount of memory, e.g. reverse-complement, k-nucleotide (for which the Clojure memory footprint can probably be reduced without a lot of effort), regex-dna, and binary-trees problems. Andy On Aug 27, 2012, at 6:58 PM, Ben Mabey wrote: > Looking at clojure's benchmarks they seem to already be highly optimized (in > terms of employing all the standard tricks). Does anyone have any idea if > more could be done to lessen the gap between java and clojure[1]? Or are > these benchmarks representative of the performance gap between clojure and > java for these types of problems? > > -Ben > > > > 1. > http://shootout.alioth.debian.org/u32/benchmark.php?test=all&lang=clojure&lang2=java > > On 8/26/12 8:07 AM, David Nolen wrote: >> I haven't found this to be the case. Java fares pretty well on Alioth. >> >> On Saturday, August 25, 2012, Stuart Sierra wrote: >> The Alioth benchmarks are somewhat unfair to JVM languages because they >> include startup time for the JVM itself and often don't run enough >> iterations to engage the optimizer. >> -S >> >> On Sat, Aug 25, 2012 at 1:51 PM, Raymond de Lacaze <[email protected]> >> wrote: >> > Here’s a performance benchmark comparison of SBCL and Clojure. >> > http://shootout.alioth.debian.org/u32/benchmark.php?test=all&lang=clojure&lang2=sbcl >> > >> >> -- >> You received this message because you are subscribed to the Google >> Groups "Clojure" group. >> To post to this group, send email to [email protected] >> Note that posts from new members are moderated - please be patient with your >> first post. >> To unsubscribe from this group, send email to >> [email protected] >> 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 post to this group, send email to [email protected] >> Note that posts from new members are moderated - please be patient with your >> first post. >> To unsubscribe from this group, send email to >> [email protected] >> 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 post to this group, send email to [email protected] > Note that posts from new members are moderated - please be patient with your > first post. > To unsubscribe from this group, send email to > [email protected] > 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 post to this group, send email to [email protected] Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/clojure?hl=en
