Hello,

New Eigen user here.

I am currently running some benchmarks for Eigen's QR factorization on an ARM development board with ARMv7 Processor rev 10, with the following features: half thumb fastmult vfp edsp thumbee neon vfpv3 tls vfpd32,

Right now, I get best results with a compile line as follows:

Code: Select all

clang++ -O3 -mfpu=neon -I/usr/local/include/eigen3/ test4.cpp -o test4

However, I read in the Eigen documentation http://eigen.tuxfamily.org/index.php?ti ... ization.3F, that I also need -mfloat-abi=softfp

However, my Debian installation doesn't let me do that as I get the following error:

Code: Select all

clang++ -O3 -mfpu=neon -mfloat-abi=softfp -I/usr/local/include/eigen3/ test4.cpp -o test4
In file included from /usr/include/features.h:398:
/usr/include/arm-linux-gnueabihf/gnu/stubs.h:7:11: [color=#FF0000]fatal[/color] error: 'gnu/stubs-soft.h' file not found

Am I missing out on performance by not being able to specify -mfloat-abi=softfp? If so, is there a way to add support for this on Debian 7 running on armhf?

More generally, are there some additional optimization or code generation flags I could be using to advantage?

Thanks for any and all help.

Charles.