Any takers for http://d.puremagic.com/issues/show_bug.cgi?id=9673?

[Vladimir Panteleev]

On Sunday, 10 March 2013 at 11:25:13 UTC, Rainer Schuetze wrote:
>
>
> On 10.03.2013 11:32, Vladimir Panteleev wrote:
>> On Sunday, 10 March 2013 at 10:27:38 UTC, Rainer Schuetze 
>> wrote:
>>> In my experience single file compilation of medium sized 
>>> projects is
>>> unacceptably slow. Much slower than what you are used to by 
>>> similar
>>> sized C++ projects.
>>
>> Even when taking advantage of multiple CPU cores?
>
> I don't have support for building on multiple cores, but trying 
> it on visuald itself (48 files) yields
>
> - combined compilation    6s
> - single file compilation 1min4s
>
> You'd need a lot of cores to be better off with single file 
> compilation.
>
> These are only the plugin files, not anything in the used 
> libraries (about 300 more files). Using dmd compiled with dmc 
> instead of cl makes these times 17s and 1min39s respectively)
>
> Almost any change causes a lot of files to be rebuilt (just 
> tried one, took 49s to build).

Do you think it has much to do with that Windows has a larger 
overhead for process creation?

I've ran some tests on Linux:

~$ git clone git://github.com/CyberShadow/DFeed.git
~$ cd DFeed
~/DFeed$ git submodule init
~/DFeed$ time rdmd --force --build-only dfeed
real    0m2.290s
user    0m1.960s
sys     0m0.304s
~/DFeed$ dmd -o- -v dfeed.d | grep '^import ' | sed 
's/.*(\(.*\))/\1/g' | grep -v '^/' > all.txt
~/DFeed$ time bash -c 'cat all.txt | xargs -n1 dmd -c'
real    0m16.935s
user    0m13.837s
sys     0m2.812s
~/DFeed$ time bash -c 'cat all.txt | xargs -n1 -P8 dmd -c'
real    0m3.703s
user    0m23.005s
sys     0m4.412s

(deprecation messages omitted)

I think 2.2s vs. 3.7s is a pretty good result. This was on a 
4-core i7 - results should be even better with the new 8-cores on 
the horizon.