4 ms·

When I wrote some cpu-bound code in Clojure which also used several java classes and libraries, I've found that the naive implementation 5x as slow as Rhino imp

When I wrote some cpu-bound code in Clojure which also used several java classes and libraries, I've found that the naive implementation 5x as slow as Rhino implementation, but when I've added some type hints (which I found out by enabling warn-on-reflection), code became ten times as fast, beating rhino twofold. I wonder if it's possible to use invokedynamic when there is an unhinted java interop to avoid drastic slowdown that I've experienced. Because it's obvious that many necessary type hints would be absent in a big real-world program.

swannodette 15y ago
In a big real world Clojure program you would probably control the amount of interop, or abstract it away. Lots of type hints is not indicative of a well-written Clojure program of any size, a good example of how this can be done over JDK 7 ForkJoin, https://gist.github.com/888733#file_forkjoin.clj https://gist.github.com/888733#file_forkjoin.clj. Note the code at the bottom has no type hints yet will be nearly as fast as if you littered code with such noise - this is because of the lovely thing that is JVM inlining.
- guard-of-terra 15y ago
  This is in the case when the program is pure-clojure. In my case, I'm trying to bring some Clojure into an existing project with a sizable Java codebase. Anyway, I think that your clojure code would use String. Or joda's DateTime and zillion other brilliantly useful classes. It's not practical to either wrap or rewrite all the Java richness. Concerning your example: Clojure also does a good work of inferring types given a few type hints, and that I good use. Just a few hints, a great speed up.
  - swannodette 15y ago
    We can agree to disagree. You have clojure.string. For Joda DateTime you have clj-time. There are a growing number of Clojure libraries that provide an idiomatic interface to Java functionality w/o resorting to pervasive type-hinting.

swannodette 15y ago

In a big real world Clojure program you would probably control the amount of interop, or abstract it away. Lots of type hints is not indicative of a well-written Clojure program of any size, a good example of how this can be done over JDK 7 ForkJoin, https://gist.github.com/888733#file_forkjoin.clj https://gist.github.com/888733#file_forkjoin.clj. Note the code at the bottom has no type hints yet will be nearly as fast as if you littered code with such noise - this is because of the lovely thing that is JVM inlining.

guard-of-terra 15y ago
This is in the case when the program is pure-clojure. In my case, I'm trying to bring some Clojure into an existing project with a sizable Java codebase. Anyway, I think that your clojure code would use String. Or joda's DateTime and zillion other brilliantly useful classes. It's not practical to either wrap or rewrite all the Java richness. Concerning your example: Clojure also does a good work of inferring types given a few type hints, and that I good use. Just a few hints, a great speed up.
- swannodette 15y ago
  We can agree to disagree. You have clojure.string. For Joda DateTime you have clj-time. There are a growing number of Clojure libraries that provide an idiomatic interface to Java functionality w/o resorting to pervasive type-hinting.