From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnaldo Carvalho de Melo Subject: [PATCH 05/43] perf bpf: Don't warn about unavailability of builtin clang, just fallback Date: Tue, 23 Jan 2018 10:12:13 -0300 Message-ID: <20180123131251.28197-6-acme@kernel.org> References: <20180123131251.28197-1-acme@kernel.org> Return-path: Received: from mail.kernel.org ([198.145.29.99]:46646 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751933AbeAWNNN (ORCPT ); Tue, 23 Jan 2018 08:13:13 -0500 In-Reply-To: <20180123131251.28197-1-acme@kernel.org> Sender: linux-perf-users-owner@vger.kernel.org List-ID: To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Arnaldo Carvalho de Melo , Adrian Hunter , David Ahern , Jiri Olsa , Namhyung Kim , Wang Nan From: Arnaldo Carvalho de Melo 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(-) 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); -- 2.14.3