Re: Compilation to native

[Stefan Monnier]

>> I don't think that a speedup of less than a factor of 2 would be worth
>> installing something that might take substantial maintenance effort.
> Hmm, I expected more speedup given that it compiles to machine code.

Maybe Richard is right, but I wouldn't be surprised if we can't go much
faster than that.  A lot of time is spent in C primitives including
binding variables and looking them up.  Also a lot of the time spent in
function call is cleverly spread and duplicated between the caller and the
callee which are at two different places, so there's a lot of opportunities
for optimization but it's very difficult to do it at all, let
alone do it automatically.

> Anyhow, while jit compilation of Emacs bytecode to native code would
> be a far-reaching goal, the most urgent issue is with CCL programs.
> Currently, CCL programs are unbearable slow.  For example, opening
> a 10MB UTF-8 file on a fast machine takes 5 min, while opening it
> without conversion is performed instantly.

And compiling CCL to native code is likely to bring much more impressive
speed ups because less time is spent in C primitives.


        Stefan