This time recorded on Ubuntu. Did I mention 64bit already?
Do not miss my session at FOTB for a live demo.
Archive for the 'personal' Category
I am back home in Germany from my trip to San Francisco where I initially announced JITB at FITC. I did not expect it to get around that quickly and that a quick-and-dirty video filmed with my phone would get so much coverage.
I want to put a lot of things regarding JITB in perspective here as a followup to the various comments that I received via mail, reddit, etc.
Flash Replacement
JITB is not a Flash replacement. Imagine a F1 race car and a family van. The family van comes with air conditioning, a radio and a lot of comfort. For the F1 car you will probably have to wear a helmet and need an engineering team to get it running.
The important factor for me is that JITB will run very fast under certain conditions. A race car is also not a jeep. JITB will not support all features of the Flash Player. If you search for a Flash replacement you might want to take a look at lightspark.
Performance
Java is slow and the world is flat. That being said I will not talk about Java performance. JITB compiles to native Java code with a certain overhead. An ActionScript 3 closure is converted into an anonymous class for instance.
JITB converts ActionScript 3 bytecode to Java bytecode at runtime and performs various optimizations. This way we can leverage the speed of the JVM for ActionScript and get great results.
That being said there is also a problem of course. Startup time is not very good. JITB and its parent project Apparat are implemented in the Scala programming language and written for multi core architectures. The startup costs are high and JITB is only useful for long living applications. However compiling ActionScript to Java can be done AOT. This means you need to deal only with the normal JVM startup time. The Flash Player API is implemented in pure Java.
The compiler used for JITB is doing relatively naive optimizations at the moment. Namely constant folding, copy propagation, dead code elimination and strength reduction. An older proof of concept version I implemented a year ago featured also loop invariant code motion, inline expansion and tail-recursive optimizations. The new compiler framework is very powerful and I will add even more algorithms and a graph coloring register allocator for example. So there is some more NP-complete fun ahead making startup time even worse.
Purpose
We need a Flash Player that performs very fast for special purposes. We could use JITB at Audiotool to render mixdowns of tracks or other companies could use it to run their ActionScript code on the server side. You can use JITB to create an offline application that runs on a client machine. You can hack JITB to do what you want. Someone could potentially write a web framework for ActionScript and you could execute that code on Google App Engine if compiled AOT. And it is definitly possible to create Android applications using ActionScript. JITB’s terrain is everything but the browser in my opinion. However I can imagine that someone would be interested in creating a plugin version. With some clever simple caching algorithms it could make sense to get around startup costs but I am not interested in doing this.
Legal
There are no legal obligations to face since both the AVM2 and SWF specifications are published by Adobe. It is also not illegal to compile code for the JVM.
ActionScript Subset
By “a subset of the language” I really mean the language and not the API. JITB supports currently only statically typed ActionScript code. However the internal language model can be adjusted to support dynamic typing as well and with Java 7 things got even easier. In fact JITB does support dynamic code as long as it is able to infer types correct. Does this mean that I am willing to implement the full Flash Player API all by myself? Hell no.
In the next weeks I will probably create a better example that is easier to understand and get some other stuff ready so that you can try everything for yourself.
My talk at FITC San Francisco is over and I want to share some of the anouncements from today with you. At the end of my talk I was showing JITB.
What you see in the YouTube video I posted a while ago is a Java program executing a SWF. For FITC I added some more code and an OpenGL based Display List renderer. In other words: I wrote a Flash Player.
However I should rephrase that statement and say I am attempting to build a Flash Player. The current state is available in the sf2010-sprint clone of Apparat. I will merge the changes into the main Apparat branch when I am back home in Germany.
JITB is currently able to translate a subset of ActionScript code at runtime into Java bytecode and runs nearly at the same speed as native Java. This is a really huge improvement compared to standard ActionScript performance. A lot of smart people worked on the JVM and made it really fast. Apparat will allow you to leverage all this hard work in the future. I am also shooting for Java interoperability at some level so that you can call Java classes from within ActionScript. Hopefully you will be able to use JITB on your desktop machine, on a server or on an Android phone. Basically everywhere Java runs.
There are still a lot of things missing. The whole Flash API needs to be implemented. And the Display List rendering needs a proper OpenGL implementation. However I thought this might be some cool stuff to share with you in its early stages.
My hope is that more people start contributing to the project. Maybe some OpenGL guru wants to take care of the Display List rendering or someone else likes to help implement the Flash API in Java.
I also showed a Raytracer by Nico Zimmermann during my presentation and promised to put the URL on my blog so here it is. His company is called Britzpetermann and the address is http://www.britzpetermann.com/.
Update: Please do not think that this implementation is 30x faster than the Flash Player developed by Adobe. One(!) microbenchmark is never a number you should count on. I would like to make clear that I never said this.
A couple of weeks ago the FlashAndTheCity conference took place in New York. Part of the program was also the FATC Awards ceremony. I am really happy, proud and thankful for winning two awards: “Most Talended Flash Developer of 2010″ and “Best Contributor of 2010″.
A big thank you goes out to the organizers and the Flash community. It really shows that the opensource work I do is appreciated and not meaningless.
Part of the prize I already received has been donated to Eugene Zatepyakin. I think he is doing great work on ASSURF and was in desperate need of an FDT license ;)
Thank you. I hope I will be able to surprise you with some new stuff later this year.
Good news everyone. The Apparat inline expansion works now to full extent after fixing some minor bugs. A complete example is also available. Just change the paths in the build.properties file and compile everything using Ant.
Use the inline feature with care. Apparat does not try to optimize your code and performs nothing but dead simple inlining. This can lead to slower code due to the creation of lots of local registers. Your code gets also much bigger and will require more space in memory. I am actually not a fan of manual inlining at all. I think it makes only sense to inline code if you have a powerful optimizer available that will cleanup the whole mess.
The fun story about this example is that the inlined version is slower using the lastes Flash Player release candidate if you have only 40.000 particles. That is why I increased the number of particles to 80.000 ;). I developed the example using an old standalone player and the inlined version was nearly twice as fast. However when I watched the example in the browser with the latest release candidate the game was completely different. Kudos to Adobe for significantly improving the Flash Player performance!
In addition to macro expansion Apparat has now inline expansion as well. It works nearly the same way as macro expansion but without most of its limitations. To define a class for inline usage it must extend apparat.inline.Inlined and all its methods must be static. However the cool thing is that you can also return values in contrast to macro expansion. You can also pass normal parameters. For instance FastMath.sin(FastMath.sqrt(2.0)) is valid code using inline expansion. It is enabled by default in TDSI.
Apparat is now available using the Scala 2.8-RC2 build. You can find appropriate downloads now on Google Code by searching for the Scala version of your choice. 7z compression on OS X should work now as well.
Apparat has another new feature called Macro Expansion. I talked about this with Nico Zimmermann at FFK in Cologne. Nico was using TDSI for a project but he was not very satisfied with it because you have to inline all inverse-square root tricks manually.
This is why Apparat has now macro expansion. I am actually not a big fan of it. I think a good compiler would do this for you without you having to go through all the steps. Unfortunately writing this compiler will take longer than the couple of hours I have spent on the macro expansion today.
So if you want to have quick and dirty inlining capabilities: this is for you. It is an easy fix for a feature a lot of people have asked for. I will continue working on TAAS to implement this much better in the future.
Apparat has a great new feature that allows you to create even smaller files. Basic SWF files are compressed using Java’s standard java.util.zip.Deflater class. This is perfectly fine. And I would even go with no compression at all during development.
However when deploying you can spend some extra time compressing your SWF files with the best tools available. 7-Zip is for instance such a tool and achieves a great compression ratio.
If you have the 7z executable on your PATH Apparat will make use of it to achieve the best compression for your SWF files. More configuration options are available here.
This feature is currently only implemented for SWF files and not SWCs. However every tool will make use of it by default. So if you are running Reducer and have no graphics in your SWF files you can still get a better compression.
An example is straight from the sources:
Note please that this SWF file does not contain any graphical assets and we got still a ratio of 18%. Our main audiotool.swf file is compressed by about 10% — about 200kb — and contains no graphical assets either.
You can download the latest Apparat on Google Code. Please note that you will need Scala 2.8 RC1 as well.
We’ve been there before, and intermediate layers between the platform and the developer ultimately produces sub-standard apps and hinders the progress of the platform.
That is so right. The first thing that comes to my mind is Java on the Mac: sub-standard, castrated and broken. The second argument is even better. Intermediate layers can hinder the progress of a platform. So true. Apple, the intermediate layer between you and the iPhone, stops you from improving the platform. You have built something cool — like Unity3D — and can empower creative people with better tools? Sorry, you are out.
The only way to improve the progress of a platform is by opening it up. Yes, I think we have been there before.
