@tlk,- Ignorance doesn't mean knowledge, it is quite the opposite... DKMS doesn't break because of headers when using clang with lto. The headers are there and complete! Everything complete with well produced binaries from LLVM/Clang.
The problem is because programs (not the headers and not the kernel) dynamically re-compilling off-tree modules, e.g.: the guest additions of Virtualbox; uses GCC with the exact same build configuration as the Kernel. i.e. the LLVM/Clang with LTO build process; thus it uses compile options used with LLVM/CLang e.g. -flto=thin (there are others); that are not compatible with GCC with GCC! Then it fails obviously because GCC has no idea what to do with those options. The Linux kernel, header, dbg, etc; all of it is perfectly made and approved by the Linux kernel team and forms part of the official kernel build documentation. see here: https://www.kernel.org/doc/html/latest/kbuild/llvm.html Not all DKMS enabled programs fail, and there's a way to fix the compile configuration, just that it is a lot of hoops to do and each build or distro environment upgrade could overwrite the config since DKMS is a distro responsibility and not Linus's when approving Linux versions. Distro upgrades don't overwrite the kernel. As for Clang vs GCC... https://www.phoronix.com/scan.php?page=article&item=clang12-gcc11-icelake&num=6 Also I have computers, servers, IoT devices all over the place and only 1 of them is zen3; most of them are ivybridge and the oldest is a penryn (core2 duo!) There is no penryn architecture option in GCC and misses out on SSE4, SSE4.1 This is what GCC offers: MMX, SSE, SSE2, SSE3 and SSSE3 https://gcc.gnu.org/onlinedocs/gcc/x86-Options.html Your statement is fake news. show me benchmarks where GCC built programs are faster than CLANG-12 otherwise you are spreading rubbish and telling people to use linux with missing or broken headers. I can only think of one where GCC beat Clang-12 and that's Python 3.9.6. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1926938 Title: Recent mainline packages are built with Hirsuite 21.04, not Focal 20.04 LTS Status in linux package in Ubuntu: Confirmed Bug description: Hi all, The Mainline wiki states that the mainline kernels are built with the previous LTS toolchain, but the recent 5.12.x and 5.11.x releases are being built with Hirsuite 21.04, and before that Groovy? If this is intentional, then the wiki should be updated to reflect the change in policy. From https://wiki.ubuntu.com/Kernel/MainlineBuilds Mainline kernel build toolchain These kernels are built with the toolchain (gcc, g++, etc.) from the previous Ubuntu LTS release. (e.g. Ubuntu 14.04 "Trusty Tahr" / 16.04 "Xenial Xerus" / 18.04 "Bionic Beaver", etc.) Therefore, out-of-tree kernel modules you already have built and installed for use with your release kernels are not likely to work with the mainline builds. The 5.12 kernel was built with GCC 10.3.0, and 5.11.16 with 10.2.0. On my Focal LTS system I have GCC 9.3.0. The Mainline kernel build toolchain These kernels are built with the toolchain (gcc, g++, etc.) from the previous Ubuntu LTS release. (e.g. Ubuntu 14.04 "Trusty Tahr" / 16.04 "Xenial Xerus" / 18.04 "Bionic Beaver", etc.) Therefore, out-of-tree kernel modules you already have built and installed for use with your release kernels are not likely to work with the mainline builds. The *linux-headers-generic* packages have unmet dependencies on 20.04 LTS. I could install Groovy built kernels fine, but the Hirsuite ones built with GCC 10.3.0 appear to require libc6 >= 2.33. So the new kernels can't be installed on Focal (libc 2.31). Thanks, Mark To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1926938/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
