[jira] [Created] (TAP5-2333) Decrease number of ThreadLocal.get calls

["Michael Mikhulya (JIRA)" <ji...@apache.org>]

Michael Mikhulya created TAP5-2333:
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             Summary: Decrease number of ThreadLocal.get calls
                 Key: TAP5-2333
                 URL: https://issues.apache.org/jira/browse/TAP5-2333
             Project: Tapestry 5
          Issue Type: Improvement
            Reporter: Michael Mikhulya


During profiling I found that ThreadLocal.get is a very hot method call.
Most frequently it is called from PerThreadOperationTracker.

PerThreadOperationTracker can be replaced with SimpleOperationTracker which I introduced in a patch.

SimpleOperationTracker only prints exception without "operations trace".

"Operations trace" can be useful during debug. So in my patch PerThreadOperationTracker is used in debug mode, but otherwise SimpleOperationTracker is used.

Please check whether this decision is good for most cases.

Performance gains are very serious. 
Time per request decreased on 11ms (23% of overall time).
All measurements are done with apache benchmark after warm up phase.

Currently my patch breaks two tests:
CoreBehaviorsTests. event_handler_return_types
MiscTests. operation_tracking_via_annotation

Both tests are broken because tests depend on 'Operation description' which is ignored by SimpleOperationTracker.

The simplest way to fix tests is to enforce using PerThreadOperationTracker for these tests.

I'm not sure whether 'Operation description' is definitely useful especially taking into account that only 2 tests become broken. We use SimpleOperationTracker on production for several months already and nobody notice that 'Operation descriptions' are absent. In all cases (for us) it was enough to see a stack trace of exception in logs.

See TAP5-2332. There is a huge amount of String.format required to track such 'operation descriptions'. By removing calculation of such 'operation descriptions' Tapestry can be made much faster.

If 'Operation descriptions' is required for some cases than we can introduce some option to enable/disable this feature.



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