5 ms·

Here's the original paper on super optimization by Alexia Massalin : http://courses.cs.washington.edu/courses/cse501/15sp/papers/massalin.pdf http://courses.cs.

by molyss 11y ago

Here's the original paper on super optimization by Alexia Massalin : http://courses.cs.washington.edu/courses/cse501/15sp/papers/massalin.pdf http://courses.cs.washington.edu/courses/cse501/15sp/papers/... I ran into it a couple years ago, after hearing from other research from her. Her papers are really impressive. I would have loved that the author of the article had mentioned her. On a side note, I wouldn't be surprised if the JIT compilers were doing some use of this, allowing some interpreted language to have better performances than compiled C on some benchmarks EDIT : formatting and JIT addition

kevinnk 11y ago
JIT compilers are time constrained so super optimization isn't a very good match.
- chrisseaton 11y ago
  Why are JIT compilers time constrained? If you have a banking system that runs all day every day, why does it matter if it takes 5 minutes to compile the hot spots at the top tier of optimisation?
  - oso2k 11y ago
    Imagine you happen to walk up to your ATM when it's Mother Banking System is in the middle hotspot compile followed by a GC pause. What would you do if your ATM took 5 minutes+ to respond to your Withdrawal Request? You'd probably freak out and worry about getting ATM card back.
    - chrisseaton 11y ago
      The program doesn't have to stop to run the JIT - it can run it on a background thread.
    - copsarebastards 11y ago
      Hotspot compilations are blocking? That would surprise and horrify me.
    - duaneb 11y ago
      I would hope an ATM isn't built to use a stop the world GC along with a stop the world jit compiler. I hope you realize how absurd you sound making an argument against jit with a real time device.
  - kevinnk 11y ago
    If you have a banking system that runs all day every day, why are you not compiling ahead of time and running super optimization then? JIT is most useful where the application or the target is highly dynamic and you aren't able to compile ahead of time.
    - chrisseaton 11y ago
      If the workload characteristic changes over time you may want to recompile with different profiling data.
WalterBright 11y ago
That paper caused a small sensation in the compiler community at the time, as everyone rushed to implement it!
- fit2rule 11y ago
  Where is this compiler community?

by molyss 11y ago

kevinnk 11y ago

JIT compilers are time constrained so super optimization isn't a very good match.

chrisseaton 11y ago
Why are JIT compilers time constrained? If you have a banking system that runs all day every day, why does it matter if it takes 5 minutes to compile the hot spots at the top tier of optimisation?
- oso2k 11y ago
  Imagine you happen to walk up to your ATM when it's Mother Banking System is in the middle hotspot compile followed by a GC pause. What would you do if your ATM took 5 minutes+ to respond to your Withdrawal Request? You'd probably freak out and worry about getting ATM card back.
  - chrisseaton 11y ago
    The program doesn't have to stop to run the JIT - it can run it on a background thread.
  - copsarebastards 11y ago
    Hotspot compilations are blocking? That would surprise and horrify me.
  - duaneb 11y ago
    I would hope an ATM isn't built to use a stop the world GC along with a stop the world jit compiler. I hope you realize how absurd you sound making an argument against jit with a real time device.
- kevinnk 11y ago
  If you have a banking system that runs all day every day, why are you not compiling ahead of time and running super optimization then? JIT is most useful where the application or the target is highly dynamic and you aren't able to compile ahead of time.
  - chrisseaton 11y ago
    If the workload characteristic changes over time you may want to recompile with different profiling data.

WalterBright 11y ago

That paper caused a small sensation in the compiler community at the time, as everyone rushed to implement it!

fit2rule 11y ago
Where is this compiler community?