Re: Performance problem with gcc 4.9.2-3 on 64 bit

Marco Atzeri wrote: >On 2/27/2015 5:49 PM, Bengt Larsson wrote: >> Below are two benchmarks that explore maximum floating point >> performance. loopm6 is double precision floating point and loopm6fp is >> parallell single-precision. They are manually unrolled multiply-add >> loops. >> >> I used to

Re: Performance problem with gcc 4.9.2-3 on 64 bit

On 2/27/2015 5:49 PM, Bengt Larsson wrote: Below are two benchmarks that explore maximum floating point performance. loopm6 is double precision floating point and loopm6fp is parallell single-precision. They are manually unrolled multiply-add loops. I used to reach 2.8 and 11 GFlops on these. No

Re: Performance problem

Vladimir Baltchev wrote: In fact you have 3 gl.h in cygwin but only one library - libGL, and it's the X11 one... Nope. There is also libopengl32.a (in /usr/lib/w32api). That's the one used by the OpenGL package, and the one using hardware acceleration if available. and: OK, guys, I understan

Re: Performance problem

Vladimir, Just a clarification. OpenGL on Cygwin is *not* slow. OpenGL support in Cygwin/XFree86 *is* slow, because they do software emulation. If you use OpenGL with X, you will either have to bear the cost of this emulation, or rewrite the UI of your application to use the non-X OpenGL packag

Re: Performance problem

OK, guys, I understand what Andre is saying, but he said cygwin is offering an opportunity to use a OpenGL package different from the X11 one. In fact I am trying to use cygwin to avoid havy porting effort. Obviousely OpenGL on cygwin is slow and I'll forget about cygwin if I have to rewrite the

Re: Performance problem

Vladimir, I think you're a little too fixated on the portability aspects such that you're not really processing what Andre is saying. If you want absolute minimal porting changes, the route you took is the proper one, but you will suffer extreme performance degradation due to the fact that all of

Re: Performance problem

In fact you have 3 gl.h in cygwin but only one library - libGL, and it's the X11 one... Vladimir Baltchev wrote: The combination OpenGL X11 works fine on Unix. That's because it is hardware accelerated on Unix. We are trying to use cygwin to port our applications on Windows. The cyg

Re: Performance problem

Vladimir Baltchev wrote: The combination OpenGL X11 works fine on Unix. That's because it is hardware accelerated on Unix. We are trying to use cygwin to port our applications on Windows. The cygwin's OpenGL gives us the dependency on the X11 cygwin simulation on Windows which is slow, I gess..

Re: Performance problem

The combination OpenGL X11 works fine on Unix. We are trying to use cygwin to port our applications on Windows. The cygwin's OpenGL gives us the dependency on the X11 cygwin simulation on Windows which is slow, I gess... - If I am interpreting the output below correctly, you ar

Re: Performance problem

If I am interpreting the output below correctly, you are developing an OpenGL program under X11; that's the main reason it is so slow. OpenGL under X11 renders everything in software, without any hardware acceleration, so it's rendering is orders of magnitude slower. It is true that Cygwin's I/

Re: Performance problem

General observation: There are quite a few more optimizations that can have *some* impact on performance. Options for processor specific code and increased math speed. Note also -O2 is not maximum optimization, -O3 is: -O3 Optimize yet more. -O3 turns on all optimizations specified by -O2

Re: Performance problem

Some amount of benchmarking has been done. You can see the email archives for reports from various interested folks with their comparisons. If you haven't already, visit . The FAQ covers some common issues that may affect your results. However, it sounds to me from t

Re: Performance problem

Thanks Larry, I know about the license. About the speed - it's several times slower... May be it worth the effort to make some benchmarking... Vlad Larry Hall wrote: Vladimir Baltchev wrote: Hi there, We are about to port Unix - Irix and Linux applications to Windows using Cygwin. However the C

Re: Performance problem

Vladimir Baltchev wrote: Hi there, We are about to port Unix - Irix and Linux applications to Windows using Cygwin. However the Cygwin version is very slow compared to Linux, even I compiled with the optimize option -O2. It is a Windows 2000, the program is a segmentation editor using Qt, OpenG