Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Tue, 15 Dec 2020 12:45:21 -0300
From:   Arnaldo Carvalho de Melo <acme@kernel.org>
To:     Jiri Olsa <jolsa@kernel.org>
Cc:     lkml <linux-kernel@vger.kernel.org>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Ingo Molnar <mingo@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Michael Petlan <mpetlan@redhat.com>,
        Ian Rogers <irogers@google.com>,
        Stephane Eranian <eranian@google.com>,
        Alexei Budankov <abudankov@huawei.com>
Subject: Re: [PATCH 5/8] perf daemon: Add signal command
Message-ID: <20201215154521.GF258566@kernel.org>
References: <20201212104358.412065-1-jolsa@kernel.org>
 <20201212104358.412065-6-jolsa@kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20201212104358.412065-6-jolsa@kernel.org>
Precedence: bulk

Em Sat, Dec 12, 2020 at 11:43:55AM +0100, Jiri Olsa escreveu:
> Allow perf daemon to send SIGUSR2 to all running sessions:
> 
>   # perf daemon
>   [1:364758] perf record -m 10M -e cycles -o /opt/perfdata/1/perf.data --overwrite --switch-output -a
>   [2:364759] perf record -m 10M -e sched:* -o /opt/perfdata/2/perf.data --overwrite --switch-output -a

The above looks ambiguous, is it starting those sessions at this point
or is it checking if there is a running daemon and then listing its
sessions?

- Arnaldo
 
>   # perf daemon -s
>   signal 12 sent to session '1 [92187]'
>   signal 12 sent to session '2 [92188]'
> 
> Or to specific one:
> 
>   # perf daemon --signal=1
>   signal 12 sent to session '1 [364758]'
> 
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
>  tools/perf/Documentation/perf-daemon.txt | 24 +++++++++++
>  tools/perf/builtin-daemon.c              | 51 +++++++++++++++++++++++-
>  2 files changed, 73 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/Documentation/perf-daemon.txt b/tools/perf/Documentation/perf-daemon.txt
> index dee39be110ba..203ec4bf704c 100644
> --- a/tools/perf/Documentation/perf-daemon.txt
> +++ b/tools/perf/Documentation/perf-daemon.txt
> @@ -30,6 +30,11 @@ OPTIONS
>  --foreground::
>  	Do not put the process in background.
>  
> +-s::
> +--signal[=session]::
> +	Send SIGUSR2 to specific session, if session is not specified,
> +	send SIGUSR2 to all sessions.
> +
>  -v::
>  --verbose::
>  	Be more verbose.
> @@ -92,6 +97,25 @@ Check sessions with more info:
>  The 'output' file is perf record output for specific session.
>  
>  
> +Send SIGUSR2 signal to all sessions:
> +
> +  # perf daemon -s
> +  signal 12 sent to session '1 [92187]'
> +  signal 12 sent to session '2 [92188]'
> +
> +Send SIGUSR2 signal to session '1':
> +
> +  # perf daemon --signal=1
> +  signal 12 sent to session '1 [364758]'
> +
> +And check that the perf data dump was trigered:
> +
> +  # cat /opt/perfdata/2/output
> +  rounding mmap pages size to 32M (8192 pages)
> +  [ perf record: dump data: Woken up 1 times ]
> +  [ perf record: Dump /opt/perfdata/2/perf.data.2020120715220385 ]
> +
> +
>  SEE ALSO
>  --------
>  linkperf:perf-record[1], linkperf:perf-config[1]
> diff --git a/tools/perf/builtin-daemon.c b/tools/perf/builtin-daemon.c
> index 7f455837d58a..c53d4ddc2b49 100644
> --- a/tools/perf/builtin-daemon.c
> +++ b/tools/perf/builtin-daemon.c
> @@ -450,9 +450,15 @@ static int setup_server_socket(struct daemon *daemon)
>  enum cmd {
>  	CMD_LIST         = 0,
>  	CMD_LIST_VERBOSE = 1,
> +	CMD_SIGNAL       = 2,
>  	CMD_MAX,
>  };
>  
> +struct cmd_signal {
> +	int	sig;
> +	char	name[16];
> +};
> +
>  static int cmd_session_list(struct daemon *daemon, FILE *out, bool simple)
>  {
>  	struct session *session;
> @@ -469,6 +475,28 @@ static int cmd_session_list(struct daemon *daemon, FILE *out, bool simple)
>  	return 0;
>  }
>  
> +static int cmd_session_kill(struct daemon *daemon, FILE *out, int fd)
> +{
> +	struct session *session;
> +	struct cmd_signal data;
> +	bool all = false;
> +
> +	if (sizeof(data) != read(fd, &data, sizeof(data)))
> +		return -1;
> +
> +	all = !strcmp(data.name, "all");
> +
> +	list_for_each_entry(session, &daemon->sessions, list) {
> +		if (all || !strcmp(data.name, session->name)) {
> +			session__signal(session, data.sig);
> +			fprintf(out, "signal %d sent to session '%s [%d]'\n",
> +				data.sig, session->name, session->pid);
> +		}
> +	}
> +
> +	return 0;
> +}
> +
>  static int handle_server_socket(struct daemon *daemon, int sock_fd)
>  {
>  	int ret = -EINVAL, fd;
> @@ -497,6 +525,9 @@ static int handle_server_socket(struct daemon *daemon, int sock_fd)
>  	case CMD_LIST_VERBOSE:
>  		ret = cmd_session_list(daemon, out, cmd == CMD_LIST);
>  		break;
> +	case CMD_SIGNAL:
> +		ret = cmd_session_kill(daemon, out, fd);
> +		break;
>  	default:
>  		break;
>  	}
> @@ -730,8 +761,9 @@ static int __cmd_daemon(struct daemon *daemon, bool foreground, const char *conf
>  	return err;
>  }
>  
> -static int send_cmd(struct daemon *daemon, u64 cmd)
> +static int send_cmd(struct daemon *daemon, u64 cmd, const char *str)
>  {
> +	struct cmd_signal data;
>  	char *line = NULL;
>  	size_t len = 0;
>  	ssize_t nread;
> @@ -747,6 +779,14 @@ static int send_cmd(struct daemon *daemon, u64 cmd)
>  	if (sizeof(cmd) != write(fd, &cmd, sizeof(cmd)))
>  		return -1;
>  
> +	if (cmd == CMD_SIGNAL) {
> +		data.sig = SIGUSR2;
> +		strncpy(data.name, str, sizeof(data.name) - 1);
> +
> +		if (sizeof(data) != write(fd, &data, sizeof(data)))
> +			return -1;
> +	}
> +
>  	in = fdopen(fd, "r");
>  	if (!in) {
>  		perror("fopen");
> @@ -770,7 +810,9 @@ static const char * const daemon_usage[] = {
>  int cmd_daemon(int argc, const char **argv)
>  {
>  	bool foreground = false;
> +	bool signal = false;
>  	const char *config = NULL;
> +	const char *signal_str = NULL;
>  	struct daemon daemon = {
>  		.sessions = LIST_HEAD_INIT(daemon.sessions),
>  		.out	  = stdout,
> @@ -780,6 +822,8 @@ int cmd_daemon(int argc, const char **argv)
>  		OPT_STRING(0, "config", &config,
>  			   "config file", "config file path"),
>  		OPT_BOOLEAN('f', "foreground", &foreground, "stay on console"),
> +		OPT_STRING_OPTARG_SET('s', "signal", &signal_str, &signal,
> +				      "signal", "send signal to session", "all"),
>  		OPT_END()
>  	};
>  
> @@ -790,5 +834,8 @@ int cmd_daemon(int argc, const char **argv)
>  	if (config)
>  		return __cmd_daemon(&daemon, foreground, config);
>  
> -	return send_cmd(&daemon, verbose ? CMD_LIST_VERBOSE : CMD_LIST);
> +	if (signal)
> +		return send_cmd(&daemon, CMD_SIGNAL, signal_str);
> +
> +	return send_cmd(&daemon, verbose ? CMD_LIST_VERBOSE : CMD_LIST, NULL);
>  }
> -- 
> 2.26.2
> 

-- 

- Arnaldo