[solved] Qt qmake compiled program is 4 times slower than compiled with cmake!?

[visoda]

Hi,

may you can help me, cause I'm quite new to linux, qmake and cmake and therefore absolutely do not know why I get the following results.

I intend to use a c++ library in my Qt project. You will find this library "here":http://www.cvlibs.net/download.php?file=libviso2.zip, including a readme.txt.

This is the CMakeLists.txt from the downloaded library:
@

project

cmake_minimum_required (VERSION 2.6)
project (libviso2)

directories

set (LIBVISO2_SRC_DIR src)

include directory

include_directories("${LIBVISO2_SRC_DIR}")

use sse3 instruction set

SET(CMAKE_CXX_FLAGS "-msse3")

sources

FILE(GLOB LIBVISO2_SRC_FILES "src/*.cpp")

make release version

set(CMAKE_BUILD_TYPE Release)

demo program

add_executable(viso2 ${LIBVISO2_SRC_FILES})
target_link_libraries (viso2 png)
@

First I created a new Qt project, inserted the the c++ files and adapted the .pro file slightly.

the .pro file:
@
#-------------------------------------------------

Project created by QtCreator 2013-11-27T22:47:00

#-------------------------------------------------

QT += core

QT -= gui

TARGET = VisoOdo
CONFIG += console
CONFIG -= app_bundle

TEMPLATE = app

SOURCES += main.cpp
viso.cpp
viso_stereo.cpp
viso_mono.cpp
triangle.cpp
reconstruction.cpp
matrix.cpp
matcher.cpp
filter.cpp

HEADERS +=
viso.h
viso_stereo.h
viso_mono.h
triangle.h
timer.h
reconstruction.h
matrix.h
matcher.h
filter.h

OTHER_FILES +=
VisoOdo.pro.user

added

QMAKE_CXXFLAGS += -msse3

https://wiki.gentoo.org/wiki/GCC_optimization

#QMAKE_CXXFLAGS += -march=native

added

unix:!macx: LIBS += -lpng
#unix:!macx: LIBS += -lpng12
@

When I compile this program with Qt and execute it the program takes ~1620ms.

But when I build this library with cmake [1] and execute it, the same program takes only ~420ms!

My problem is I have to use Qt, but it's far to slow.
Is there a way to get with Qt the same performance as with Cmake?

May has it something to do with the msse3? I also tried “QMAKE_CXXFLAGS += -march=native”, but the result is the same.

Please tell me if I should send you the Qt and Cmake project files.

Thanks a lot for your help!

---

My system:

Dell Workstation M6700
Intel(R) Core(TM) i7-3740QM CPU @ 2.70GHz
Linux Ubuntu 12.04 LTS
64 bit
QtCreator 2.8.1, Based on Qt 5.1.1 (GCC 4.6.1, 64 bit)

[1]
I do not use any additional flags at compiling with cmake:
2) Type 'cmake .'
3) Type 'make'
4) Run './viso2 2010_03_09_drive_0019'

[bobEdwards]

Hello,

Perhaps try adding:

CONFIG += release

to your qmake .pro file

[visoda]

Hello,

thats it! The qmake builded program takes now 430ms --> equal to cmake.

Many thanks for your help!!!!