linux-kernel - [PATCH v5 07/13] perf stat: factor out event handling loop into dispatch

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Message-ID: <7f200782-c0ad-16f2-e000-bb4743ea976d@linux.intel.com>
Date:   Mon, 1 Jun 2020 18:56:33 +0300
From:   Alexey Budankov <alexey.budankov@...ux.intel.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Jiri Olsa <jolsa@...hat.com>, Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Andi Kleen <ak@...ux.intel.com>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: [PATCH v5 07/13] perf stat: factor out event handling loop into
 dispatch_events()


Consolidate event dispatching loops for launch, attach and system wide
monitoring use cases into common dispatch_events() function. If passed
pid contains valid pid i.e. doesn't equal to -1 then the function returns
pid process exit status in case the process terminates during monitoring.

Signed-off-by: Alexey Budankov <alexey.budankov@...ux.intel.com>
---
 tools/perf/builtin-stat.c | 35 ++++++++++++++++++++++++-----------
 1 file changed, 24 insertions(+), 11 deletions(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index dc7506be8bbd..8eeaf92912d8 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -504,6 +504,27 @@ static bool is_target_alive(struct target *_target,
 	return false;
 }
 
+static int dispatch_events(pid_t pid, bool timeout, int interval, int *times, struct timespec *ts)
+{
+	bool stop = false;
+	int child = 0, status = 0;
+
+	while (1) {
+		if (pid != -1)
+			child = waitpid(pid, &status, WNOHANG);
+		else
+			child = is_target_alive(&target, evsel_list->core.threads) == false ? 1 : 0;
+
+		if (done || stop || child)
+			break;
+
+		nanosleep(ts, NULL);
+		stop = process_timeout(timeout, interval, times);
+	}
+
+	return status;
+}
+
 enum counter_recovery {
 	COUNTER_SKIP,
 	COUNTER_RETRY,
@@ -575,7 +596,6 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
 	struct affinity affinity;
 	int i, cpu;
 	bool second_pass = false;
-	bool stop = false;
 
 	if (interval) {
 		ts.tv_sec  = interval / USEC_PER_MSEC;
@@ -744,12 +764,8 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
 		perf_evlist__start_workload(evsel_list);
 		enable_counters();
 
-		if (interval || timeout) {
-			while (!stop && !waitpid(child_pid, &status, WNOHANG)) {
-				nanosleep(&ts, NULL);
-				stop = process_timeout(timeout, interval, &times);
-			}
-		}
+		if (interval || timeout)
+			status = dispatch_events(child_pid, timeout, interval, &times, &ts);
 		if (child_pid != -1) {
 			if (timeout)
 				kill(child_pid, SIGTERM);
@@ -766,10 +782,7 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
 			psignal(WTERMSIG(status), argv[0]);
 	} else {
 		enable_counters();
-		while (!done && !stop && is_target_alive(&target, evsel_list->core.threads)) {
-			nanosleep(&ts, NULL);
-			stop = process_timeout(timeout, interval, &times);
-		}
+		dispatch_events(-1, timeout, interval, &times, &ts);
 	}
 
 	disable_counters();
-- 
2.24.1