11-Jan-2013 05:43, Timon Gehr пишет:
On 01/10/2013 08:52 PM, Dmitry Olshansky wrote:
[snip]
Cool! I'd love to take even the very preliminary peek at the speed
profile of this CTFE engine.
If you are interested I'd love to test a small (the code though contains
a lot of static data) CTFE benchmark that is the bottleneck in the
compilation of current ctRegex.
See the attachment here:
http://d.puremagic.com/issues/show_bug.cgi?id=7442
would be nice to see some rough numbers for this vs DMD.
I'll let you know as soon as the example runs. Currently this is blocked
by the missing implementation for the following language features:
- import declarations
- UFCS
- Optional parens on function calls
- Struct literals
- Static struct data
- debug declarations
- Some of the built-in array operations
- Missing object.d (no string, size_t, hash_t alias.)
- (static) foreach
- __ctfe
I guess that core.bitop intrinsics too. Either way, thanks in advance.
I will prioritize those features. Except import declarations, they are
mostly easy to implement, but I haven't gotten around to them yet.
For the meantime, maybe these quick measurements are somewhat useful:
They truly are. As I've been long wondering that CTFE could be quite
fast if it wasn't for it's current architecture in DMD. Just needed the
hard data to go by.
int[] erathos(int x){
bool[] p;
for(int i=0;i<=x;i++) p~=true;
for(int i=3;i*i<=x;i+=2){
if(p[i]) for(int k=i*i;k<=x;k=k+i) p[k]=false;
}
int[] r;
if(x>=2) r~=2;
for(int i=3;i<=x;i+=2) if(p[i]) r~=i;
return r;
}
pragma(msg, "erathos: ",erathos(40000).length);
The frontend (32-bit dmd build, without -inline, otherwise DMD ICEs):
$ time ./d erathos.d
erathos: 4203U
real 0m0.077s
user 0m0.076s
sys 0m0.000s
DMD 2.060 (64 bit):
$ time dmd -o- erathos.d
erathos: 4203u
real 0m2.594s
user 0m0.716s
sys 0m1.696s
...
pragma(msg, "erathos: ",erathos(400000)); // (that is one 0 more)
The frontend:
erathos: 33860U
real 0m0.662s
user 0m0.660s
sys 0m0.000s
DMD: brings down the machine
pragma(msg, "erathos: ",erathos(4000000)); // (yet another 0 more)
The frontend:
erathos: 283146U
real 0m6.867s
user 0m6.832s
sys 0m0.016s
// pragma(msg, "erathos: ",erathos(4000000));
void main(){
import std.stdio;
writeln(erathos(4000000).length);
}
$ dmd -O -release -inline -noboundscheck erathos.d && time ./erathos
dmd: module.c:829: void Module::semantic3(): Assertion `semanticstarted
== 2' failed.
I bet this one was fixed in 2.061, I've recently seen the similar bug as
resolved "works for me".
(I'll see if it also fails with DMD 2.061.)
$ dmd -O -release -noboundscheck erathos.d && time ./erathos
283146
real 0m0.144s
user 0m0.132s
sys 0m0.008s
So CTFE in the front end seems to be ~50 times slower than a optimized
DMD build of the same code in this case. But note that it is powered by
a simple-minded bytecode interpreter I hacked together mostly during two
weekends.
Yes, yes and yes! Simple bytecode interpreter is what I've been waiting
for :)
(the array append is the one from druntime) A lot more is
possible. I guess it is already fast enough to power std.regex.
Sure and a simple threaded-code interpreter should make it fly (when D
has e.g. explicit tail call).
--
Dmitry Olshansky
