** !! deprecated !!**

Overview

• Branch : wip_tuning
• Maintenair : David Bernard exp-backport-2.8.1.final) (for Galileo and Helios)
• Goals : see below
• Update-site : http://alchim31.net/scala-ide/update-wip_tuning or build it yourself

Goals :

1. remove/reduce the eclipse freeze (except from user request, force clean+build)
2. allow GC to free more memory when needed to build,... (eg : free some information from previous build (from same or other project))
3. use less CPU
   • avoid too many compilation, sometimes not uptodate data (AST) is acceptable
   • less allocation, reuse object if available
4. reduce memory used to build

To rich those goals, there is several axes/startegies, Tuning is allowing to provide/configure/use them and to collect feedback information. The majority of proposal should impact scala-ide, but during investigation some bug or enhancement can be only allowed by modification of scala-compiler (TODO : define the way to follow in this case : fork full scalac, move patched classed under a scala-ide project, use aspect to monkey patch scalac like for jdt ?).

Some major difference vs command line compilation :

• compiler could be resident
• there is several project to compile
• each project could use several compiler (presentation vs builder)

How to help :

• provide feedback about tuning feature
• capture and share information about freeze, memory leak,... in this page or in tickets (I'll try to share mime here) Eg when my eclipse start to freeze :
  1. I start a visualvm (could be download alone or use the one provide in jdk 1.6.0_21)
  2. I open the monitor of the eclipse process
  3. I wait few second, take a screenshot (see samples below) for gc and memory issue I also do a Heap dump (and save it for postmordem analyze with VisualVM or Mat).

Roadmap :

DONE :

• add a Tuning Preferences page (change need to restart eclipse)
• allow user to choose between strongly caching the last Compilation Result of single File or soft caching every Compilation Result
• add StopWatch about call to compilers (open web browser to http://localhost:9999/ to see data or to disable collect)
• provide a update-site for wip_tuning, or something to allow user to test tuning without need to build there own plugin at http://alchim31.net/scala-ide/update-wip_tuning

TODO :

• allow several type of reference ScalaPresentationCompiler and EclipseBuilder : Strong, Soft, Weak
• provide a Log.info and enable it from TuningPreferences
• StopWatch (if feature keep)
  • dynamics change (Property listener) of goupe enable/disable
  • provide a button to start/stop web server
  • provide a View for the html output provide by internal webserver
  • if need, change for implementations (don't forget dependencies,...) :
  • Stopwatch from A. Boisvert (currently used)
  • metrics
  • ostrich
  • javasimon

Scala-compiler's issues :

• #3679 : scalac memory leak with NoPhase

Stuff to explore :

• share stuff (data, 'service') between builder and presentation compiler of a common project
• share stuff (data, 'service') between compilers of several projects (eg: Names tables : big table of char)
• using a background job with +/- fixed rate to run compilation (start with ScalaPresentationCompilation) about eclipse periodic task/job, (instead of nsc.interactive.Global TaskThread/Executor) see
  • doc about Job into http://help.eclipse.org/galileo/
  • eclipse Concurrency infrastructure and next pages from Eclipse Plug-in Developer Guide
  • Defining a background Job to run periodically (including interesting comments)
• to avoid compiling every time and freeze at wrong time, only run compilation after some idle time or now (end user request)
• may be using aspect to inject interceptor for StopWatch and other metric instead of hardcode aroundMethod call by hand (everywhere) with a trait
  • http://eclipse.org/aspectj/doc/released/progguide/index.html
  • Trait vs Aspect in scala
• deeply understand scalac code
• learn more GC tuning

original idea from : mailing-list plugin tuning

Screenshots :

CPU eat by GC Activity [[image:2010-07-15-0015171680x1050scrot.png]]

Memory Usage [[image:2010-07-15-0012421680x1050scrot.png]]

Number of Compilation run on startup [[image:2010-09-11-1054131680x1048scrot.png]]