From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754569Ab3JCQ6q (ORCPT ); Thu, 3 Oct 2013 12:58:46 -0400 Received: from mail-qc0-f172.google.com ([209.85.216.172]:44966 "EHLO mail-qc0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753738Ab3JCQ6p (ORCPT ); Thu, 3 Oct 2013 12:58:45 -0400 Date: Thu, 3 Oct 2013 13:58:32 -0300 From: Arnaldo Carvalho de Melo To: Ramkumar Ramachandra Cc: LKML , Ingo Molnar Subject: Re: [PATCH] perf tool: more user-friendly errors from trace Message-ID: <20131003165832.GA2436@ghostprotocols.net> References: <1380788891-31908-1-git-send-email-artagnon@gmail.com> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="ReaqsoxgOBHFXBhH" Content-Disposition: inline In-Reply-To: <1380788891-31908-1-git-send-email-artagnon@gmail.com> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --ReaqsoxgOBHFXBhH Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Em Thu, Oct 03, 2013 at 01:58:11PM +0530, Ramkumar Ramachandra escreveu: > Currently, execution of 'perf trace' reports the following cryptic > message to the user: > > $ perf trace > Couldn't read the raw_syscalls tracepoints information! > > Now, it prints a detailed message: What about the one attached instead? It [acme@zoo ~]$ mount | grep debugfs [acme@zoo ~]$ [acme@zoo ~]$ perf trace usleep 1 Is debugfs mounted? Try 'sudo mount -t debugfs nodev /sys/kernel/debug' [acme@zoo ~]$ sudo mkdir /d [acme@zoo ~]$ sudo mount -t debugfs nodev /d [acme@zoo ~]$ mount | grep debugfs nodev on /d type debugfs (rw,relatime) [acme@zoo ~]$ [acme@zoo ~]$ perf trace usleep 1 Couldn't access debugfs. Try 'sudo mount -o remount,mode=755 /d' [acme@zoo ~]$ sudo mount -o remount,mode=755 /d [acme@zoo ~]$ perf trace -e mmap usleep 1 0.956 ( 0.004 ms): mmap(len: 4096, prot: READ|WRITE, flags: PRIVATE|ANONYMOUS, fd: 4294967295) = 0x46dfc000 0.995 ( 0.004 ms): mmap(len: 125871, prot: READ, flags: PRIVATE, fd: 3 ) = 0x46ddd000 1.045 ( 0.005 ms): mmap(addr: 0x3da4800000, len: 2135088, prot: EXEC|READ, flags: PRIVATE|DENYWRITE, fd: 3) = 0xa4800000 1.068 ( 0.005 ms): mmap(addr: 0x3da4a08000, len: 8192, prot: READ|WRITE, flags: PRIVATE|DENYWRITE|FIXED, fd: 3, off: 32768) = 0xa4a08000 1.109 ( 0.005 ms): mmap(addr: 0x3d93400000, len: 3896312, prot: EXEC|READ, flags: PRIVATE|DENYWRITE, fd: 3) = 0x93400000 1.125 ( 0.006 ms): mmap(addr: 0x3d937ad000, len: 24576, prot: READ|WRITE, flags: PRIVATE|DENYWRITE|FIXED, fd: 3, off: 1757184) = 0x937ad000 1.134 ( 0.004 ms): mmap(addr: 0x3d937b3000, len: 17400, prot: READ|WRITE, flags: PRIVATE|ANONYMOUS|FIXED, fd: 4294967295) = 0x937b3000 1.147 ( 0.003 ms): mmap(len: 4096, prot: READ|WRITE, flags: PRIVATE|ANONYMOUS, fd: 4294967295) = 0x46ddc000 1.160 ( 0.003 ms): mmap(len: 8192, prot: READ|WRITE, flags: PRIVATE|ANONYMOUS, fd: 4294967295) = 0x46dda000 [acme@zoo ~]$ --ReaqsoxgOBHFXBhH Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="tracepoint_error_message.patch" diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c index 1bb8f15..8a35943 100644 --- a/tools/perf/builtin-trace.c +++ b/tools/perf/builtin-trace.c @@ -1501,17 +1501,13 @@ static int trace__run(struct trace *trace, int argc, const char **argv) } if (perf_evlist__add_newtp(evlist, "raw_syscalls", "sys_enter", trace__sys_enter) || - perf_evlist__add_newtp(evlist, "raw_syscalls", "sys_exit", trace__sys_exit)) { - fprintf(trace->output, "Couldn't read the raw_syscalls tracepoints information!\n"); - goto out_delete_evlist; - } + perf_evlist__add_newtp(evlist, "raw_syscalls", "sys_exit", trace__sys_exit)) + goto out_error_tp; if (trace->sched && perf_evlist__add_newtp(evlist, "sched", "sched_stat_runtime", - trace__sched_stat_runtime)) { - fprintf(trace->output, "Couldn't read the sched_stat_runtime tracepoint information!\n"); - goto out_delete_evlist; - } + trace__sched_stat_runtime)) + goto out_error_tp; err = perf_evlist__create_maps(evlist, &trace->opts.target); if (err < 0) { @@ -1628,6 +1624,23 @@ out_delete_evlist: out: trace->live = false; return err; +out_error_tp: + switch (errno) { + case ENOENT: + fputs("Is debugfs mounted? Try 'sudo mount -t debugfs nodev /sys/kernel/debug'\n", trace->output); + break; + case EACCES: + fprintf(trace->output, + "Couldn't access debugfs. Try 'sudo mount -o remount,mode=755 %s'\n", + debugfs_mountpoint); + break; + default: + fprintf(trace->output, "Can't trace: %s!\n", sys_errlist[errno]); + break; + + } + + goto out_unmap_evlist; } static int trace__replay(struct trace *trace) --ReaqsoxgOBHFXBhH--