This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
gcj Linpack performance
- To: gcc at gcc dot gnu dot org
- Subject: gcj Linpack performance
- From: Florian Schintke <schintke at zib dot de>
- Date: Tue, 10 Jul 2001 12:35:24 +0200
- Reply-To: Florian Schintke <schintke at zib dot de>
Hi all,
I just tested the performace of gcj 3.0 with the Linpack
benchmark
http://www.netlib.org/benchmark/linpackjava/Linpack.java
and got the following results:
The used system
> uname -a
Linux host 2.2.18 #1 Fri Jan 19 22:10:35 GMT 2001 i686 unknown
> cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 8
model name : Pentium III (Coppermine)
stepping : 3
cpu MHz : 797.559
cache size : 256 KB
fdiv_bug : no
hlt_bug : no
sep_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 2
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 sep mtrr pge mca
cmov pat pse36 mmx fxsr xmm
bogomips : 1592.52
256MB main memory
###### gcj
> gcc -v
Reading specs from /usr/local/lib/gcc-lib/i686-pc-linux-gnu/3.0/specs
Configured with: ./configure
Thread model: single
gcc version 3.0
> gcj --version
3.0
> gcj -O3 --main=Linpack -funroll-all-loops Linpack.java
> ./a.out
Mflops/s: 24.833 Time: 1.73 secs Norm Res: 4.7
Precision: 2.220446049250313E-16
###### java 1.1.8
> /usr/lib/java/bin/java -version
java version "1.1.8"
> /usr/lib/java/bin/javac Linpack.java
> /usr/lib/java/bin/java Linpack
Mflops/s: 4.812 Time: 8.93 secs Norm Res: 6.34
Precision: 2.220446049250313E-16
###### IBM java JDK 1.3.0
> /usr/lib/jdk1.3/bin/java -version
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0)
Classic VM (build 1.3.0, J2RE 1.3.0 IBM build cx130-20001025 (JIT
enabled: jitc))
> /usr/lib/jdk1.3/bin/javac Linpack.java
> /usr/lib/jdk1.3/bin/java Linpack
Mflops/s: 46.877 Time: 0.92 secs Norm Res: 6.54
Precision: 2.220446049250313E-16
###### Compiled with java 1.1.8, executed with IBM JIT
> /usr/lib/java/bin/java -version
java version "1.1.8"
> /usr/lib/java/bin/javac Linpack.java
> /usr/lib/jdk1.3/bin/java -version
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0)
Classic VM (build 1.3.0, J2RE 1.3.0 IBM build cx130-20001025 (JIT
enabled: jitc))
> /usr/lib/jdk1.3/bin/java Linpack
Mflops/s: 44.778 Time: 0.96 secs Norm Res: 6.54
Precision: 2.220446049250313E-16
Why is gcj not as fast as IBMs JIT compiler?
Maybe this info helps you to look how to improve the performance.
Florian Schintke
--
Florian Schintke <schintke@zib.de>, http://www.zib.de/schintke/