[phobos] std.parallelism: Request for review

[Russel Winder]

On Sat, 2011-02-26 at 14:43 -0500, David Simcha wrote:

> I feel like the build process for the benchmarks is so trivial that no
> formal process is required.    Besides, I know nothing about build
> tools because, for anything I write, I tend to keep the build process
> so simple and stupid that nothing more than a 2-line script or the
> builtin build system for Code::Blocks is required.  

OK, I used SCons as it is the right tool for dealing with directories of
independent compilations.  

> For std.parallelism, as you appear to have figured out, you need to
> put it in your Phobos source folder, edit the makefile and recompile
> Phobos.  Each benchmark is completely self-contained.  The way I run
> them is to open them in Code::Blocks (or whatever IDE happens to be
> available) and hit "build and run".  dmd -O -inline -release
> someBenchmark.d && ./someBenchmark would also work fine.

I don't go anywhere near recompiling Phobos, I just use what comes in
the distribution.  I keep extra stuff in ~/lib/D and use the DPATH,
LIBPATH and LIBS capabilities.

        |> scons
        /usr/bin/python /home/Checkouts/Mercurial/SCons/bootstrap/src/script/scons.py
        scons: Reading SConscript files ...
        scons: done reading SConscript files.
        scons: Building targets ...
        dmd -I. -I/home/users/russel/lib/D -m64 -c -ofeuclidean.o euclidean.d
        gcc -o euclidean euclidean.o -L/home/users/russel/lib.Linux.x86_64 -L/home/users/russel/lib.Linux.x86_64/DMD2/lib64 -lparallelism -lphobos2 -lpthread -lm -lrt
        dmd -I. -I/home/users/russel/lib/D -m64 -c -ofmatrixInversion.o matrixInversion.d
        gcc -o matrixInversion matrixInversion.o -L/home/users/russel/lib.Linux.x86_64 -L/home/users/russel/lib.Linux.x86_64/DMD2/lib64 -lparallelism -lphobos2 -lpthread -lm -lrt
        dmd -I. -I/home/users/russel/lib/D -m64 -c -ofmillionSqrt.o millionSqrt.d
        gcc -o millionSqrt millionSqrt.o -L/home/users/russel/lib.Linux.x86_64 -L/home/users/russel/lib.Linux.x86_64/DMD2/lib64 -lparallelism -lphobos2 -lpthread -lm -lrt
        dmd -I. -I/home/users/russel/lib/D -m64 -c -ofparallelSort.o parallelSort.d
        gcc -o parallelSort parallelSort.o -L/home/users/russel/lib.Linux.x86_64 -L/home/users/russel/lib.Linux.x86_64/DMD2/lib64 -lparallelism -lphobos2 -lpthread -lm -lrt
        dmd -I. -I/home/users/russel/lib/D -m64 -c -ofpipelining.o pipelining.d
        gcc -o pipelining pipelining.o -L/home/users/russel/lib.Linux.x86_64 -L/home/users/russel/lib.Linux.x86_64/DMD2/lib64 -lparallelism -lphobos2 -lpthread -lm -lrt
        scons: done building targets.


        |> for f in euclidean matrixInversion millionSqrt parallelSort pipelining ; do echo "==========================  $f  ==============================" && $f ; done
        ==========================  euclidean  ==============================
        Serial reduce:  5182 milliseconds.
        Parallel reduce with 1 cores:  5183 milliseconds.
        ==========================  matrixInversion  ==============================
        Inverted a 256 x 256 matrix serially in 63 milliseconds.
        Inverted a 256 x 256 matrix using 1 cores in 64 milliseconds.
        ==========================  millionSqrt  ==============================
        Parallel benchmarks being done with 1 cores.
        Did serial millionSqrt in 975 milliseconds.
        Did parallel foreach millionSqrt in 1263 milliseconds.
        Did parallel map millionSqrt in 979 milliseconds.
        ==========================  parallelSort  ==============================
        Serial quick sort:  6256 milliseconds.
        Parallel quick sort:  6317 milliseconds.
        ==========================  pipelining  ==============================
        Did serial string -> float, euclid in 2606 milliseconds.
        Did parallel string -> float, euclid with 1 cores in 2576 milliseconds.


So we have the problem that the code is failing to observe that I have 8
cores on my machine :-((

-- 
Russel.
=============================================================================
Dr Russel Winder      t: +44 20 7585 2200   voip: sip:russel.winder at ekiga.net
41 Buckmaster Road    m: +44 7770 465 077   xmpp: russel at russel.org.uk
London SW11 1EN, UK   w: www.russel.org.uk  skype: russel_winder
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