https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93327
Bug ID: 93327
Summary: Performance degradation of povray benchmark from gcc
8.3.1 to gcc 9.2.1
Product: gcc
Version: 9.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: driver
Assignee: unassigned at gcc dot gnu.org
Reporter: ming.chen1986 at gmail dot com
Target Milestone: ---
I'm seeing a performance degradation of povray benchmark from gcc 8.3.1 to
9.2.1 on a dual-socket Intel Xeon Platinum 8280L system. Details can be found
below. Please let me know if any other information is needed. Thanks.
Hardware spec:
CPU: Dual-socket Intel Xeon Platinum 8280L
Motherboard: Intel S2600WF
RAM: 384 GB
OS: Clear Linux 31890 (also reproduced the issue with Ubuntu 20.04 daily build
20200107)
Steps to reproduce:
# download and build the benchmark with g++ 8.3.1 and 9.2.1, respectively
wget http://www.phoronix-test-suite.com/benchmark-files/povray-3.7.0.7.tar.xz
tar -xf povray-3.7.0.7.tar.xz
cd povray-3.7.0.7/
cd unix/
autoupdate
./prebuild.sh
cd ..
automake --add-missing
LIBS="-lboost_system" ./configure COMPILED_BY="PhoronixTestSuite"
--with-boost-thread=boost_thread
make
# run the benchmark
echo 1 | ./unix/povray -benchmark
Expected results:
The benchmark binaries compiled by g++ 8.3.1 and 9.2.1 should produce similar
scores.
Actual results:
Score of g++ 8.3.1 compiled povray: 14 seconds (less is better)
Score of g++ 9.2.1 compiled povray: vary between 25 - 60 seconds (less is
better)
Output of g++ -v (8.3.1):
Using built-in specs.
COLLECT_GCC=g++-8
COLLECT_LTO_WRAPPER=/usr/lib64/gcc/x86_64-generic-linux/8/lto-wrapper
Target: x86_64-generic-linux
Configured with: ../gcc-8.3.0/configure --program-suffix=-8 --prefix=/usr
--with-pkgversion='Clear Linux OS for Intel Architecture' --libdir=/usr/lib64/
--enable-libstdcxx-pch --libexecdir=/usr/lib64 --with-system-zlib
--enable-shared --enable-gnu-indirect-function --disable-vtable-verify
--enable-threads=posix --enable-__cxa_atexit --enable-plugin
--enable-ld=default --enable-clocale=gnu --disable-multiarch --disable-multilib
--enable-lto --enable-linker-build-id --build=x86_64-generic-linux
--target=x86_64-generic-linux --enable-languages=c,c++ --enable-bootstrap
--with-ppl=yes --with-isl --includedir=/usr/include --exec-prefix=/usr
--with-glibc-version=2.28 --disable-libunwind-exceptions --with-gnu-ld
--with-tune=haswell --with-arch=westmere --enable-cet
--with-gcc-major-version-only --enable-default-pie --disable-libmpx
Thread model: posix
gcc version 8.3.1 20190513 gcc-8-branch@271113 (Clear Linux OS for Intel
Architecture)
Output of g++ -v (9.2.1):
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/lib64/gcc/x86_64-generic-linux/9/lto-wrapper
Target: x86_64-generic-linux
Configured with: ../gcc-9.2.0/configure --prefix=/usr --with-pkgversion='Clear
Linux OS for Intel Architecture' --libdir=/usr/lib64 --enable-libstdcxx-pch
--libexecdir=/usr/lib64 --with-system-zlib --enable-shared
--enable-gnu-indirect-function --disable-vtable-verify --enable-threads=posix
--enable-__cxa_atexit --enable-plugin --enable-ld=default --enable-clocale=gnu
--disable-multiarch --enable-multilib --enable-lto --disable-werror
--enable-linker-build-id --build=x86_64-generic-linux
--target=x86_64-generic-linux --enable-languages=c,c++,fortran,go
--enable-bootstrap --with-ppl=yes --with-isl --includedir=/usr/include
--exec-prefix=/usr --with-glibc-version=2.19 --disable-libunwind-exceptions
--with-gnu-ld --with-tune=haswell --with-arch=westmere --enable-cet
--disable-libmpx --with-gcc-major-version-only --enable-default-pie
Thread model: posix
gcc version 9.2.1 20191223 gcc-9-branch@279714 (Clear Linux OS for Intel
Architecture)
