[jira] Commented: (HARMONY-4549) [drlvm][jit][opt][perf]throwing/catching exceptions works slowly

["Mikhail Fursov (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HARMONY-4549?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12516010 ] 

Mikhail Fursov commented on HARMONY-4549:
-----------------------------------------

After Test2.test method is inlined the 'throwable' variable will become a dead code. 
the   'throw new TException()' can be replaced by a simple branch instruction without any VM call.

I propose closing this issue only after no exception at all is thrown in generated code for the example in this test.

BTW:
after we have no exception thrown in the example above we can file another performance issue: empty loop elimination. AFAIK Jitrino.OPT does not have this optimization today.


> [drlvm][jit][opt][perf]throwing/catching exceptions works slowly
> ----------------------------------------------------------------
>
>                 Key: HARMONY-4549
>                 URL: https://issues.apache.org/jira/browse/HARMONY-4549
>             Project: Harmony
>          Issue Type: Bug
>          Components: DRLVM
>            Reporter: Vladimir Strigun
>
> The test below shows that exception throwing/catching operations works slower on Harmony in comparison win Sun. 
> Results of test execution:
> java client: 1200 msec
> java server: 1000 
> harmony server: 5700 msec
> Small test:
> public class TestExceptions {
>     public static void main(String[] args) {
>         //warmup VM first
>         tryRaiseExceptions(1);
>         long start = System.currentTimeMillis();
>         tryRaiseExceptions(1000000);
>         long res = System.currentTimeMillis() -start;
>         System.out.println("completed in "+res+" msec");
>     }
>     public static void tryRaiseExceptions(int n) {
>         for(int i=0; i<n; i++) 
>             try{
>                 throw new TException();
>             }catch(TException throwable){
>                 TException ts = Test2.test(throwable);
>             }
>     }
> }
> class Test2  {
>    public static TException test(TException thr) {
>        return thr;
>    }
> }
> class TException extends RuntimeException {}

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