Re: [Boost-users] g++ compilation is slow with Boost's constructs

Subject: Re: [Boost-users] g++ compilation is slow with Boost's constructs
From: OvermindDL1 (overminddl1_at_[hidden])
Date: 2010-09-10 21:50:58

On Fri, Sep 10, 2010 at 7:38 PM, OvermindDL1 <overminddl1_at_[hidden]> wrote:
> On Fri, Sep 10, 2010 at 7:37 PM, OvermindDL1 <overminddl1_at_[hidden]> wrote:
>> On Thu, Sep 9, 2010 at 10:17 AM, Ilya Murav'jov <muravev_at_[hidden]> wrote:
>>> Jason Merrill пишет:
>>>> > On 09/08/2010 07:40 AM, Ilya Murav'jov wrote:
>>>>> >> Dave Abrahams пишет:
>>>>>> >>> G++4.5 implements O(1) template lookup, which could have a
>>> significant
>>>>>> >>> effect for Boost users.
>>>>> >>
>>>>> >> Thanks for the info. I've built gcc-4.5.1 myself and got not very
>>>>> >> comforting results: g++4.2 is still 'unbeaten', g++4.5 is 15% slower.
>>>> >
>>>> > Hmm, that's disappointing. Â I grabbed the source file you mentioned, but
>>>> > it seems to depend on other headers from your project; if you send me a
>>>> > preprocessed file I'll try to take a look at what's slowing it down
>>>> > sometime soon.
>>>> >
>>>> > Jason
>>>> >
>>>
>>> After some experiments I've done a clear example. It shows that
>>> boost::lambda::bind() invocation cost 0.1 sec. Here is the code:
>>>
>>> //////////////////// begin ////////////////////////
>>>
>>> #include <boost/lambda/bind.hpp> Â  // boost::lambda::bind
>>> #include <boost/function.hpp> Â  Â  Â // boost::function
>>>
>>> typedef boost::function<void()> TestFunctor;
>>>
>>> template<int value>
>>> struct TestStruct
>>> {
>>> };
>>>
>>> #define IMPL_DEF_(Idx, Type) void Impl ## Idx(Type) {} \
>>> void TestImpl ## Idx() Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  \
>>> { Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â \
>>> Â  Â TestFunctor fnr; Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  \
>>> Â  Â fnr = boost::lambda::bind(&Impl ## Idx, Type()); Â \
>>> } \
>>> /**/
>>>
>>> #define IMPL_DEF(Idx) IMPL_DEF_(Idx, TestStruct<Idx>)
>>>
>>> #define IMPL_DEF_10_(Idx) \
>>> IMPL_DEF(Idx ## 0) \
>>> IMPL_DEF(Idx ## 1) \
>>> IMPL_DEF(Idx ## 2) \
>>> IMPL_DEF(Idx ## 3) \
>>> IMPL_DEF(Idx ## 4) \
>>> IMPL_DEF(Idx ## 5) \
>>> IMPL_DEF(Idx ## 6) \
>>> IMPL_DEF(Idx ## 7) \
>>> IMPL_DEF(Idx ## 8) \
>>> IMPL_DEF(Idx ## 9) \
>>> /**/
>>>
>>> #define IMPL_DEF_10(Idx) IMPL_DEF_10_(Idx)
>>>
>>> IMPL_DEF_10(__LINE__)
>>> IMPL_DEF_10(__LINE__)
>>> IMPL_DEF_10(__LINE__)
>>> IMPL_DEF_10(__LINE__)
>>> IMPL_DEF_10(__LINE__)
>>> IMPL_DEF_10(__LINE__)
>>> IMPL_DEF_10(__LINE__)
>>> IMPL_DEF_10(__LINE__)
>>> IMPL_DEF_10(__LINE__)
>>> IMPL_DEF_10(__LINE__)
>>>
>>> //////////////////// end ////////////////////////
>>>
>>> It does 100 invocations of boost::lambda::bind() with various types.
>>> Benchmarks with "-c -g -O0 -pipe", Boost 1.44:
>>>
>>> G++ 4.2.4: 14.75 sec
>>> G++ 4.5.1: 09.57 sec
>>>
>>> P.S. It shows that  g++4.5 is quicker, though.  :)  Later I try to do
>>> examples with other constructs (BOOST_FOREACH, Boost.Range, B.Function)
>>> to find out where g++4.2 is better.
>>>
>>> P.S.S. I suggest to make comparison among varios compilers (i.e., clang,
>>> msvc, icc) with this test. It is interesting to see the quickest (don't
>>> forget to include your CPU).
>>
>> I have an AMD Phenom II CPU, 3.2ghz, my times:
>>
>> home:/home/overminddl1/projects/testingrandom# g++ -v
>> Using built-in specs.
>> Target: i486-linux-gnu
>> Configured with: ../src/configure -v --with-pkgversion='Ubuntu
>> 4.4.3-4ubuntu5'
>> --with-bugurl=file:///usr/share/doc/gcc-4.4/README.Bugs
>> --enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr
>> --enable-shared --enable-multiarch --enable-linker-build-id
>> --with-system-zlib --libexecdir=/usr/lib --without-included-gettext
>> --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.4
>> --program-suffix=-4.4 --enable-nls --enable-clocale=gnu
>> --enable-libstdcxx-debug --enable-plugin --enable-objc-gc
>> --enable-targets=all --disable-werror --with-arch-32=i486
>> --with-tune=generic --enable-checking=release --build=i486-linux-gnu
>> --host=i486-linux-gnu --target=i486-linux-gnu
>> Thread model: posix
>> gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5)
>> home:/home/overminddl1/projects/testingrandom# ~/llvm/Release/bin/clang++ -v
>> clang version 2.8 (trunk 113038)
>> Target: i386-pc-linux-gnu
>> Thread model: posix
>> home:/home/overminddl1/projects/testingrandom# time g++ test.cpp
>> /usr/lib/gcc/i486-linux-gnu/4.4.3/../../../../lib/crt1.o: In function `_start':
>> (.text+0x18): undefined reference to `main'
>> collect2: ld returned 1 exit status
>>
>> real    0m8.504s
>> user    0m5.336s
>> sys     0m0.184s
>> home:/home/overminddl1/projects/testingrandom# time
>> ~/llvm/Release/bin/clang++ test.cpp
>> /usr/lib/gcc/i486-linux-gnu/4.4.3/../../../../lib/crt1.o: In function `_start':
>> (.text+0x18): undefined reference to `main'
>> collect2: ld returned 1 exit status
>> clang: error: linker (via gcc) command failed with exit code 1 (use -v
>> to see invocation)
>>
>> real    0m3.443s
>> user    0m2.524s
>> sys     0m0.188s
>>
>>
>> However, clang++ usually does not compile code that runs quite as fast
>> as g++ as of yet, but they are getting close, and yes, I know my g++
>> is old, it is the stock install.
>
>
> Guess I should use the same parameters you did, here it is:
> home:/home/overminddl1/projects/testingrandom# time g++ test.cpp -c -g -O0 -pipe
>
> real    0m9.404s
> user    0m5.500s
> sys     0m1.608s
> home:/home/overminddl1/projects/testingrandom# time
> ~/llvm/Release/bin/clang++ test.cpp -c -g -O0 -pipe
>
> real    0m4.644s
> user    0m2.948s
> sys     0m0.240s

And compiling it in MSVC2k5 I got:
Release:
    Build Time 1:28
Debug:
    Build Time 1:00

In MSVC2k5 I was using WinXP 32-bit, for clang++/g++ I was using
Ubuntu 10.04 in a virtual machine with hardware virtualization enabled
on top of this WinXP 32-bit machine.