Exupery is not JIT (was Re: Cryptographic Primitives)
tim at rowledge.org
Fri Oct 6 23:38:55 UTC 2006
On 6-Oct-06, at 4:25 PM, <bryce at kampjes.demon.co.uk> wrote:
> Andreas Raab writes:
>> J J wrote:
>>>> No. First, Exupery is not a JIT.
>>> I had been told it was. In this list actually.
>> Yeah, it's quite confusing actually. I found the statement that
>> "[Exupery is] a "JIT" for Squeak that doesn't compile just in time"
>> which (to me) makes no sense as "JIT" stands for "just in time" so
>> could a JIT not compile just in time? ;-)
> When Exupery is running in a background thread a user shouldn't
> notice that it's not a "real" JIT. So calling it a JIT is fair.
Actually I don't think JIT is a sensible description at all; it isn't
accurate and it doesn't really indicate the advantages that Exupery
could have. For example, no extra startup costs, easier extension/
maintenance/optimising because it is written in a sensible language,
access to all of the reflexive capabilities of the system, trivial
fallback if the system is run on an unsupported platform (it just
doesn't do the compiles and leaves everything to the interpreter),
potential for using a spoon-like inter-image communication system to
allow the compiles to run in a different image/machine, and... well I
could probably go on.
JIT really has been tied to a very limited concept of "oh I need
this, let's compile something, er, now where was I?" approach. The
compiler has to be internal to the VM and so far as I'm aware is
pretty much tied to C/C++ or worse.
Exupery is CALIL - Compile At Leisure, Install Later. Oh, and you
could even have setup where an external compiler-server caches a lot
of methods and avoids even doing the compile a lot of the time.
tim Rowledge; tim at rowledge.org; http://www.rowledge.org/tim
User: A harmless drudge.
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