Commit f33cbe72 authored by Arnaldo Carvalho de Melo's avatar Arnaldo Carvalho de Melo
Browse files

perf evlist: Send the errno in the signal when workload fails 

When a tool uses perf_evlist__start_workload and the supplied workload
fails (e.g.: its binary wasn't found), perror was being used to print
the error reason.

This is undesirable, as the caller may be a GUI, when it wants to have
total control of the error reporting process.

So move to using sigaction(SA_SIGINFO) + siginfo_t->sa_value->sival_int
to communicate to the caller the errno and let it print it using the UI
of its choosing.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-epgcv7kjq8ll2udqfken92pz@git.kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 6af206fd

tools/perf/builtin-record.c

+37 −2
Original line number Diff line number Diff line
@@ -341,6 +341,22 @@ static void record__init_features(struct record *rec) 
		perf_header__clear_feat(&session->header, HEADER_BRANCH_STACK);

}



static volatile int workload_exec_errno;



/*

 * perf_evlist__prepare_workload will send a SIGUSR1

 * if the fork fails, since we asked by setting its

 * want_signal to true.

 */

static void workload_exec_failed_signal(int signo, siginfo_t *info,

					void *ucontext __maybe_unused)

{

	workload_exec_errno = info->si_value.sival_int;

	done = 1;

	signr = signo;

	child_finished = 1;

}



static int __cmd_record(struct record *rec, int argc, const char **argv)

{

	int err;
@@ -359,7 +375,6 @@ static int __cmd_record(struct record *rec, int argc, const char **argv) 
	on_exit(record__sig_exit, rec);

	signal(SIGCHLD, sig_handler);

	signal(SIGINT, sig_handler);

	signal(SIGUSR1, sig_handler);

	signal(SIGTERM, sig_handler);



	session = perf_session__new(file, false, NULL);
@@ -492,8 +507,20 @@ static int __cmd_record(struct record *rec, int argc, const char **argv) 
	/*

	 * Let the child rip

	 */

	if (forks)

	if (forks) {

		struct sigaction act = {

			.sa_flags     = SA_SIGINFO,

			.sa_sigaction = workload_exec_failed_signal,

		};

		/*

		 * perf_evlist__prepare_workload will, after we call

		 * perf_evlist__start_Workload, send a SIGUSR1 if the exec call

		 * fails, that we will catch in workload_signal to flip

		 * workload_exec_errno.

 		 */

		sigaction(SIGUSR1, &act, NULL);

		perf_evlist__start_workload(evsel_list);

	}



	for (;;) {

		int hits = rec->samples;
@@ -521,6 +548,14 @@ static int __cmd_record(struct record *rec, int argc, const char **argv) 
		}

	}



	if (forks && workload_exec_errno) {

		char msg[512];

		const char *emsg = strerror_r(workload_exec_errno, msg, sizeof(msg));

		pr_err("Workload failed: %s\n", emsg);

		err = -1;

		goto out_delete_session;

	}



	if (quiet || signr == SIGUSR1)

		return 0;

tools/perf/builtin-stat.c

+15 −6
Original line number Diff line number Diff line
@@ -58,6 +58,7 @@ 
#include "util/thread.h"

#include "util/thread_map.h"



#include <signal.h>

#include <stdlib.h>

#include <sys/prctl.h>

#include <locale.h>
@@ -509,16 +510,17 @@ static void handle_initial_delay(void) 
	}

}



static volatile bool workload_exec_failed;

static volatile int workload_exec_errno;



/*

 * perf_evlist__prepare_workload will send a SIGUSR1

 * if the fork fails, since we asked by setting its

 * want_signal to true.

 */

static void workload_exec_failed_signal(int signo __maybe_unused)

static void workload_exec_failed_signal(int signo __maybe_unused, siginfo_t *info,

					void *ucontext __maybe_unused)

{

	workload_exec_failed = true;

	workload_exec_errno = info->si_value.sival_int;

}



static int __run_perf_stat(int argc, const char **argv)
@@ -596,13 +598,17 @@ static int __run_perf_stat(int argc, const char **argv) 
	clock_gettime(CLOCK_MONOTONIC, &ref_time);



	if (forks) {

		struct sigaction act = {

			.sa_flags     = SA_SIGINFO,

			.sa_sigaction = workload_exec_failed_signal,

		};

		/*

		 * perf_evlist__prepare_workload will, after we call

		 * perf_evlist__start_Workload, send a SIGUSR1 if the exec call

		 * fails, that we will catch in workload_signal to flip

		 * workload_exec_failed.

		 * workload_exec_errno.

 		 */

		signal(SIGUSR1, workload_exec_failed_signal);

		sigaction(SIGUSR1, &act, NULL);



		perf_evlist__start_workload(evsel_list);

		handle_initial_delay();
@@ -615,8 +621,11 @@ static int __run_perf_stat(int argc, const char **argv) 
		}

		wait(&status);



		if (workload_exec_failed)

		if (workload_exec_errno) {

			const char *emsg = strerror_r(workload_exec_errno, msg, sizeof(msg));

			pr_err("Workload failed: %s\n", emsg);

			return -1;

		}



		if (WIFSIGNALED(status))

			psignal(WTERMSIG(status), argv[0]);

tools/perf/util/evlist.c

+8 −3
Original line number Diff line number Diff line
@@ -1073,9 +1073,14 @@ int perf_evlist__prepare_workload(struct perf_evlist *evlist, struct target *tar 


		execvp(argv[0], (char **)argv);



		if (want_signal) {

			union sigval val;



			val.sival_int = errno;

			if (sigqueue(getppid(), SIGUSR1, val))

				perror(argv[0]);

		} else

			perror(argv[0]);

		if (want_signal)

			kill(getppid(), SIGUSR1);

		exit(-1);

	}

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