From 872523233d640c21ce13ea51269c5c031ebb2f78 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Thu, 18 Jan 2018 13:07:00 -0300 Subject: perf bpf: Don't warn about unavailability of builtin clang, just fallback When clang is not linked with 'perf' we should just add a debug message about that before doing the fallback to calling the external compiler. I.e. just the "-95" warning below gets turned into a debug message: # cat sys_enter_open.c #include "bpf.h" SEC("syscalls:sys_enter_open") int func(void *ctx) { struct { char *ptr; char path[256]; } filename = { .ptr = *((char **)(ctx + 16)), }; int len = bpf_probe_read_str(filename.path, sizeof(filename.path), filename.ptr); if (len > 0) { if (len == 1) perf_event_output(ctx, &__bpf_stdout__, BPF_F_CURRENT_CPU, &filename, len + sizeof(filename.ptr)); else if (len < 256) perf_event_output(ctx, &__bpf_stdout__, BPF_F_CURRENT_CPU, &filename, len + sizeof(filename.ptr)); } return 0; } # trace -e open,sys_enter_open.c bpf: builtin compilation failed: -95, try external compiler 0.000 ( ): __bpf_stdout__:@......./proc/self/task/11160/comm..) 0.014 ( 0.116 ms): qemu-system-x8/6721 open(filename: /proc/self/task/11160/comm, flags: RDWR) = 91 2335.411 ( ): __bpf_stdout__:FB..~.../etc/resolv.conf....) 2335.421 ( 0.030 ms): chronyd/883 open(filename: /etc/resolv.conf, flags: CLOEXEC) = 5 ^C# Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: https://lkml.kernel.org/n/tip-z5aak9oay448ffj37giz94yr@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/bpf-loader.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools') diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c index 72c107fcbc5a..ab2598af91eb 100644 --- a/tools/perf/util/bpf-loader.c +++ b/tools/perf/util/bpf-loader.c @@ -94,7 +94,7 @@ struct bpf_object *bpf__prepare_load(const char *filename, bool source) err = perf_clang__compile_bpf(filename, &obj_buf, &obj_buf_sz); perf_clang__cleanup(); if (err) { - pr_warning("bpf: builtin compilation failed: %d, try external compiler\n", err); + pr_debug("bpf: builtin compilation failed: %d, try external compiler\n", err); err = llvm__compile_bpf(filename, &obj_buf, &obj_buf_sz); if (err) return ERR_PTR(-BPF_LOADER_ERRNO__COMPILE); -- cgit