linux-kernel - [PATCH 7/8] perf data: Enable stream flush within processing

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Message-Id: <1417623842-14331-8-git-send-email-jolsa@kernel.org>
Date:	Wed,  3 Dec 2014 17:24:01 +0100
From:	Jiri Olsa <jolsa@...nel.org>
To:	linux-kernel@...r.kernel.org
Cc:	Jiri Olsa <jolsa@...nel.org>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	David Ahern <dsahern@...il.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Jeremie Galarneau <jgalar@...icios.com>,
	Namhyung Kim <namhyung@...il.com>,
	Paul Mackerras <paulus@...ba.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
	Tom Zanussi <tzanussi@...il.com>
Subject: [PATCH 7/8] perf data: Enable stream flush within processing

For big data files the size of data allocated for stream
instance could get really high. It's needed to flush the
data out of the stream once in a while.

Unfortunately there's no size indication in the stream
object, so we govern the flush based on the number of
stored events. Current flush limit is set ot 100000
events.

Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
Cc: David Ahern <dsahern@...il.com>
Cc: Frederic Weisbecker <fweisbec@...il.com>
Cc: Jeremie Galarneau <jgalar@...icios.com>
Cc: Jiri Olsa <jolsa@...nel.org>
Cc: Namhyung Kim <namhyung@...il.com>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc: Tom Zanussi <tzanussi@...il.com>
Signed-off-by: Jiri Olsa <jolsa@...nel.org>
---
 tools/perf/util/data-convert-bt.c | 28 +++++++++++++++++++++++++---
 1 file changed, 25 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/data-convert-bt.c b/tools/perf/util/data-convert-bt.c
index 2bc70b8d128d..df95fac399d7 100644
--- a/tools/perf/util/data-convert-bt.c
+++ b/tools/perf/util/data-convert-bt.c
@@ -43,6 +43,7 @@ struct evsel_priv {
 struct ctf_stream {
 	struct bt_ctf_stream *stream;
 	int cpu;
+	u32 count;
 };
 
 struct ctf_writer {
@@ -392,7 +393,10 @@ static int ctf_stream__flush(struct ctf_stream *cs)
 		if (err)
 			pr_err("CTF stream %d flush failed\n", cs->cpu);
 
-		pr("Flush stream for cpu %d\n", cs->cpu);
+		pr("Flush stream for cpu %d (%u samples)\n",
+		   cs->cpu, cs->count);
+
+		cs->count = 0;
 	}
 
 	return err;
@@ -490,6 +494,19 @@ static int get_sample_cpu(struct ctf_writer *cw, struct perf_sample *sample,
 	return cpu;
 }
 
+#define STREAM_FLUSH_COUNT 100000
+
+/*
+ * Currently we have no other way to determine the
+ * time for the stream flush other than keep track
+ * of the number of events and check it against
+ * threshold.
+ */
+static bool is_flush_needed(struct ctf_stream *cs)
+{
+	return cs->count >= STREAM_FLUSH_COUNT;
+}
+
 static int process_sample_event(struct perf_tool *tool,
 				union perf_event *_event __maybe_unused,
 				struct perf_sample *sample,
@@ -535,8 +552,13 @@ static int process_sample_event(struct perf_tool *tool,
 	}
 
 	cs = ctf_stream(cw, get_sample_cpu(cw, sample, evsel));
-	if (cs)
+	if (cs) {
+		if (is_flush_needed(cs))
+			ctf_stream__flush(cs);
+
+		cs->count++;
 		bt_ctf_stream_append_event(cs->stream, event);
+	}
 
 	bt_ctf_event_put(event);
 	return cs ? 0 : -1;
@@ -724,7 +746,7 @@ static int setup_streams(struct ctf_writer *cw, struct perf_session *session)
 	 * Try to get the number of cpus used in the data file,
 	 * if not present fallback to the MAX_CPUS.
 	 */
-	if (!ph)
+	if (!ph || !ph->env.nr_cpus_avail)
 		ncpus = MAX_CPUS;
 	else
 		ncpus = ph->env.nr_cpus_avail;
-- 
1.9.3

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