[LLVMdev] FYI: Phoronix GCC vs. LLVM-GCC benchmarks

[Olivier Meurant]

On Tue, Sep 15, 2009 at 5:35 PM, David Greene <dag at cray.com> wrote:

>
> Remember, the goal here isn't to show how great LLVM is.  It's to get an
> honest assessment of where we are at.  Phoronix did us a big favor.
>  Getting
> more details about his tests would help us even more.
>

It's exactly what I'm trying to do. I'm not even a LLVM contributor, so I
don't feel responsible for a good or bad performances of LLVM. :)
Anyway, thanks for pointing this target differences. After some hours at
recompiling gcc, here we are :

Some information on the test platform :

cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=9.04
DISTRIB_CODENAME=jaunty
DISTRIB_DESCRIPTION="Ubuntu 9.04"

uname -a
Linux zaraki 2.6.28-15-generic #49-Ubuntu SMP Tue Aug 18 18:40:08 UTC 2009
i686 GNU/Linux

/proc/cpuinfo
dual core Intel(R) Core(TM)2 CPU X6800  @ 2.93GHz (cache size 4096)

llvm-gcc -v
Using built-in specs.
Target: i686-pc-linux-gnu
Configured with: ../llvm-gcc4.2-2.5.source/configure
--prefix=/mounts/zion/disks/0/localhome/tbrethou/2.5/prerelease2/llvm-gcc/obj/../install
--program-prefix=llvm-
--enable-llvm=/localhome/tbrethou/2.5/prerelease2/llvm-2.5/
--disable-bootstrap --enable-languages=c,c++,fortran
Thread model: posix
gcc version 4.2.1 (Based on Apple Inc. build 5636) (LLVM build 2.5)
(Binary from official x86 2.5 release)

gcc -v
Using built-in specs.
Target: i686-pc-linux-gnu
Configured with: ./configure --prefix=/usr/local
Thread model: posix
gcc version 4.4.1 (GCC)

The compilation line are :
gcc -o bin src.c -O3
llvm-gcc -o bin src.c -O3


Results :
LLVM average : 13553161.95
gcc average : 14624441.45
Average : gcc is better with 8%

The full report :
        "LLVM"  "GCC"   "Difference"    "Difference %"

"Run 1" 13842616        14693115.8      -850499.8       -6.14
"Run 2" 13773202.9      14785734.9      -1012532        -7.35
"Run 3" 13671309.3      14985114        -1313804.7      -9.61
"Run 4" 12916939        14640392.9      -1723453.9      -13.34
"Run 5" 13572133.3      14425575        -853441.7       -6.29
"Run 6" 13810096.5      14694240.6      -884144.1       -6.4
"Run 7" 13427435.8      14695094.6      -1267658.8      -9.44
"Run 8" 14056659.9      14468968.4      -412308.5       -2.93
"Run 9" 13699125.3      14373360.9      -674235.6       -4.92
"Run 10 12762101.5      14482817.4      -1720715.9      -13.48

"Average"       13553161.95     14624441.45     -1071279.5      -7.99
"Standard deviation"    412810.77       187898.68       430895.31       3.46

Is there again something wrong on this test ?

Olivier.
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