• Miroslav Benes's avatar
    kbuild: use -flive-patching when CONFIG_LIVEPATCH is enabled · 43bd3a95
    Miroslav Benes authored
    GCC 9 introduces a new option, -flive-patching. It disables certain
    optimizations which could make a compilation unsafe for later live
    patching of the running kernel.
    
    The option is used only if CONFIG_LIVEPATCH is enabled and $(CC)
    supports it.
    
    Performance impact of the option was measured on three different
    Intel machines - two bigger NUMA boxes and one smaller UMA box. Kernel
    intensive (IO, scheduling, networking) benchmarks were selected, plus a
    set of HPC workloads from NAS Parallel Benchmark. The tests were done on
    upstream kernel 5.0-rc8 with openSUSE Leap 15.0 userspace.
    
    The majority of the tests is unaffected. The only significant exception
    is the scheduler section which suffers 1-3% degradation.
    Evaluated-by: default avatarGiovanni Gherdovich <ggherdovich@suse.cz>
    Signed-off-by: default avatarMiroslav Benes <mbenes@suse.cz>
    Acked-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
    Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
    43bd3a95
Makefile 59.5 KB