To build this program successfully with clang, there have three compiler options need to be specified: - Header file path: tools/perf/include/bpf; - Specify architecture; - Define macro __NR_CPUS__. This patch add comments to explain the reasons for building failure and give two examples for llvm.clang-opt variable, one is for x86_64 architecture and another is for aarch64 architecture. Signed-off-by: Leo Yan <leo.yan@xxxxxxxxxx> --- .../examples/bpf/augmented_raw_syscalls.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/tools/perf/examples/bpf/augmented_raw_syscalls.c b/tools/perf/examples/bpf/augmented_raw_syscalls.c index f4ed101b697d..5adc0b3bb351 100644 --- a/tools/perf/examples/bpf/augmented_raw_syscalls.c +++ b/tools/perf/examples/bpf/augmented_raw_syscalls.c @@ -6,6 +6,25 @@ * * perf trace -e tools/perf/examples/bpf/augmented_raw_syscalls.c cat /etc/passwd > /dev/null * + * This program include two header files 'unistd.h' and 'pid_filter.h', which + * are placed in the folder tools/perf/include/bpf, but this folder is not + * included in env $KERNEL_INC_OPTIONS and it leads to compilation failure. + * For building this code, we also need to specify architecture and define macro + * __NR_CPUS__. To resolve these issues, variable llvm.clang-opt can be set in + * the file ~/.perfconfig: + * + * E.g. Test on a platform with 8 CPUs with x86_64 architecture: + * + * [llvm] + * clang-opt = "-D__NR_CPUS__=8 -D__x86_64__ \ + * -I./tools/perf/include/bpf" + * + * E.g. Test on a platform with 5 CPUs with aarch64 architecture: + * + * [llvm] + * clang-opt = "-D__NR_CPUS__=5 -D__aarch64__ \ + * -I./tools/perf/include/bpf" + * This exactly matches what is marshalled into the raw_syscall:sys_enter * payload expected by the 'perf trace' beautifiers. * -- 2.17.1
