Caching Reflector.getMethods, as described below, works pretty well.
Performance seems acceptable for now. Startup time is still dramatic,
need to investigate. Considering releasing changes as a fork on
github is anybody is interested.
On Sat, Jan 31, 2009 at 8:35 PM, Remco van 't Veer <rwvtv...@gmail.com> wrote:
> Some naive caching code does speed up my sample by 4 times. Will
> investigate further later this week, need to take my flu to bed now..
>
>
> diff --git a/src/jvm/clojure/lang/Reflector.java
> b/src/jvm/clojure/lang/Reflector.java
> index f530b78..eccebb8 100644
> --- a/src/jvm/clojure/lang/Reflector.java
> +++ b/src/jvm/clojure/lang/Reflector.java
> @@ -296,7 +296,21 @@ static public Field getField(Class c, String
> name, boolean getStatics){
> return null;
> }
>
> +static private java.util.Map<String,List> methodsCache = new
> java.util.HashMap<String,List>();
> +
> static public List getMethods(Class c, int arity, String name,
> boolean getStatics){
> + synchronized (methodsCache) {
> + String key = "" + c + "-" + arity + " " + name + " " + getStatics;
> + if (methodsCache.containsKey(key)) {
> + return methodsCache.get(key);
> + } else {
> + List methods = originalGetMethods(c, arity, name, getStatics);
> + methodsCache.put(key, methods);
> + return methods;
> + }
> + }
> +}
> +static public List originalGetMethods(Class c, int arity, String
> name, boolean getStatics){
> Method[] allmethods = c.getMethods();
> ArrayList methods = new ArrayList();
> ArrayList bridgeMethods = new ArrayList();
>
>
> On Sat, Jan 31, 2009 at 3:55 PM, Remco van 't Veer <rwvtv...@gmail.com> wrote:
>> I've been playing around with clojure on the android platform. To my
>> surprise it was pretty easy to get running, after removing the bean
>> method from the clojure.jar as hinted by Rich somewhere. Of course
>> clojure code needs to be compiled AOT and eval doesn't work, as was to
>> be expected, but all seems to run fine otherwise.
>>
>> There's a problem though, it's really slow.. I've played around with
>> the tracing tools of the android sdk and noticed about half of the
>> time spend is doing reflection related things. Reflection on Android/
>> Dalvik is known to be slow. At the top of the method list sorted by
>> exclusive times is clojure/lang/Reflector.getMethods with a 10% score
>> of total time spend, followed by java/lang/reflect/
>> ReflectionAccessImpl.clone, java/lang/reflect/Method.<init>, java/
>> lang/ClassCache.deepCopy, java/lang/reflect/Method.getName and java/
>> lang/String.equals and java/lang/reflect/AccessibleObject.<init>.
>>
>> My test case was pretty simpel; get the public-time-line from twitter,
>> parse it with xml/parse (needs a small tweak to work on android btw),
>> populate some struct-maps and display a listview. Unfortunately this
>> simple task takes about 12 seconds to complete on a g1 phone.
>>
>> So I setup *warn-on-reflection* and put type hints in all the
>> appropriate places but didn't detect any performance improvements.
>> Then I ran compile-clojure in the clojure source tree with an adjusted
>> compiler to see the reflection warning in the core. This yields about
>> 40 warnings and I wonder if fixing those will improve performance at
>> all.
>>
>> Another approach is to try and speedup clojure/lang/
>> Reflector.getMethods by caching results. Any idea's on what route
>> will get me the best results?
>>
>> Thanks,
>> Remco
>
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