From 51a09d8f9aa05a9dc56baaec3f160df2802b0f7b Mon Sep 17 00:00:00 2001 From: Changbin Du Date: Sun, 10 May 2020 23:06:11 +0800 Subject: [PATCH] perf ftrace: Detect workload failure Currently there's no error message prompted if we failed to start workload. And we still get some trace which is confusing. Let's tell users what happened. Committer testing: Before: # perf ftrace nonsense |& head 5) | switch_mm_irqs_off() { 5) 0.400 us | load_new_mm_cr3(); 5) 3.261 us | } ------------------------------------------ 5) -0 => <...>-3494 ------------------------------------------ 5) | finish_task_switch() { 5) ==========> | 5) | smp_irq_work_interrupt() { # type nonsense -bash: type: nonsense: not found # After: # perf ftrace nonsense |& head workload failed: No such file or directory # type nonsense -bash: type: nonsense: not found # Signed-off-by: Changbin Du Tested-by: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Steven Rostedt (VMware) Link: http://lore.kernel.org/lkml/20200510150628.16610-3-changbin.du@gmail.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-ftrace.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c index b7d3fb5..2bfc1b0 100644 --- a/tools/perf/builtin-ftrace.c +++ b/tools/perf/builtin-ftrace.c @@ -45,6 +45,7 @@ struct filter_entry { char name[]; }; +static volatile int workload_exec_errno; static bool done; static void sig_handler(int sig __maybe_unused) @@ -63,7 +64,7 @@ static void ftrace__workload_exec_failed_signal(int signo __maybe_unused, siginfo_t *info __maybe_unused, void *ucontext __maybe_unused) { - /* workload_exec_errno = info->si_value.sival_int; */ + workload_exec_errno = info->si_value.sival_int; done = true; } @@ -383,6 +384,14 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv) write_tracing_file("tracing_on", "0"); + if (workload_exec_errno) { + const char *emsg = str_error_r(workload_exec_errno, buf, sizeof(buf)); + /* flush stdout first so below error msg appears at the end. */ + fflush(stdout); + pr_err("workload failed: %s\n", emsg); + goto out_close_fd; + } + /* read remaining buffer contents */ while (true) { int n = read(trace_fd, buf, sizeof(buf)); @@ -397,7 +406,7 @@ out_close_fd: out_reset: reset_tracing_files(ftrace); out: - return done ? 0 : -1; + return (done && !workload_exec_errno) ? 0 : -1; } static int perf_ftrace_config(const char *var, const char *value, void *cb) -- 2.7.4