Hi I know this is an OpenBLAS specific question, probably better posted on an OpenBLAS forum, but I just want to check that I have followed the correct steps to rebuild the Debian/Ubuntu OpenBLAS package on my Raspberry Pi 4 Model B running Ubuntu 20.04 aarch64. Following the instructions in the source debian/README.Debian and the Debian BuildingTutorial I did: $ mkdir -p build/openblas $ chown -R _apt:root build $ cd build/openblas $ sudo apt-get source openblas $ sudo apt-get build-dep openblas $ cd openblas-0.3.8+ds $ sudo cp cpuid_arm64.c cpuid_arm64.c.original $ sudo vim cpuid_arm64.c $ diff cpuid_arm64.c cpuid_arm64.c.original 275c275 < printf("#define L2_SIZE 1048576\n"); --- > printf("#define L2_SIZE 524288\n"); 278c278 < printf("#define DTB_DEFAULT_ENTRIES 32\n"); --- > printf("#define DTB_DEFAULT_ENTRIES 64\n"); $ DEB_BUILD_OPTIONS=custom dpkg-buildpackage -uc -b cd .. $ sudo apt remove libopenblas0-serial $ sudo dpkg -i libopenblas0-serial_0.3.8+ds-1_arm64.deb $ sudo update-alternatives --config libblas.so.3-aarch64-linux-gnu Everything appears to have worked fine. Note, the DTB_DEFAULT_ENTRIES is directly from the Arm Cortex-A72 TRM. And, the result was that the performance of my Pi running a Linpack benchmark was exactly the same as pre-L2 change. I was, possibly naively, expected a modest improvement with a doubling of L2 cache size. I would be grateful for confirmation that I have followed the correct procedure to make a change to the package source code. Kind regards |