Hello All,

I found one difference between gcc-linaro-5.1 vs gcc-linaro-4.8 while I’m doing lmbench benchmark test for our LS1043 (cortex-A53).

While using gcc-linaro-4.8, gcc will generate advanced SIMD instructions (like as ld1, etc), however, gcc-linaro-5.1 will not generate advance SIMD instructions. This will cause big performance gap between gcc-4.8 and gcc-5.1 for lmbench memory bandwidth “fcp” test (bw_mem program).

 

My compiler flags is “-O3 -mcpu=cortex-a53”. I also tried several different compiler flags (“-O3 -mcpu=cortex-a53+fp+simd”, “-O2 -ftree-vectorize -mcpu=cortex-a53”,  “-O3 -ftree-vectorize -mcpu=cortex-a53”), all of them doesn’t work.

 

Gcc-5.1 toolchain was downloaded from following link:

 

https://snapshots.linaro.org/openembedded/sources/gcc-linaro-5.1-snapshot-2015.06-1-x86_64_aarch64-linux-gnu.tar.xz

 

Can I have your comments on this?

 

 

Thanks

Ron