Merge tag 'perf-core-for-mingo-20160429' of git://git.kernel.org/pub/…

…scm/linux/kernel/git/acme/linux into perf/core

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

User visible changes:

 - Allow generate timestamped suffixed multiple perf.data files upon receiving
   SIGUSR2 in 'perf record', to slice a long running monitoring session, allowing
   to dump uninteresting sessions (Wang Nan)

 - Handle ENOMEM for perf_event_max_stack + PERF_SAMPLE_CALLCHAIN
   in perf_evsel__open_strerror(), showing a more informative
   message when the request call stack depth can't be allocated by
   the kernel (Arnaldo Carvalho de Melo)

Infrastructure changes:

 - Use strbuf for making strings in 'perf probe' (Masami Hiramatsu)

 - Do not use sizeof on pointer type, not a problem since its a pointer to
   pointer, fix none the less. Found by Coccinelle (Vaishali Thakkar)

Cleanups:

 - Fix for Coverity found issues in the bpf feature build test (Florian Fainelli)

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

tools/build/feature/test-bpf.c

@@ -27,10 +27,9 @@ int main(void)
 	attr.log_level = 0;
 	attr.kern_version = 0;
 
-	attr = attr;
 	/*
 	 * Test existence of __NR_bpf and BPF_PROG_LOAD.
 	 * This call should fail if we run the testcase.
 	 */
-	return syscall(__NR_bpf, BPF_PROG_LOAD, attr, sizeof(attr));
+	return syscall(__NR_bpf, BPF_PROG_LOAD, &attr, sizeof(attr));
 }

tools/perf/Documentation/perf-record.txt

@@ -347,6 +347,19 @@ Configure all used events to run in kernel space.
 --all-user::
 Configure all used events to run in user space.
 
+--timestamp-filename
+Append timestamp to output file name.
+
+--switch-output::
+Generate multiple perf.data files, timestamp prefixed, switching to a new one
+when receiving a SIGUSR2.
+
+A possible use case is to, given an external event, slice the perf.data file
+that gets then processed, possibly via a perf script, to decide if that
+particular perf.data snapshot should be kept or not.
+
+Implies --timestamp-filename, --no-buildid and --no-buildid-cache.
+
 SEE ALSO
 --------
 linkperf:perf-stat[1], linkperf:perf-list[1]

tools/perf/builtin-record.c

@@ -34,6 +34,7 @@
 #include "util/parse-regs-options.h"
 #include "util/llvm-utils.h"
 #include "util/bpf-loader.h"
+#include "util/trigger.h"
 #include "asm/bug.h"
 
 #include <unistd.h>
@@ -57,6 +58,7 @@ struct record {
 	bool			no_buildid_cache_set;
 	bool			buildid_all;
 	bool			timestamp_filename;
+	bool			switch_output;
 	unsigned long long	samples;
 };
 
@@ -127,44 +129,9 @@ static volatile int done;
 static volatile int signr = -1;
 static volatile int child_finished;
 
-static volatile enum {
-	AUXTRACE_SNAPSHOT_OFF = -1,
-	AUXTRACE_SNAPSHOT_DISABLED = 0,
-	AUXTRACE_SNAPSHOT_ENABLED = 1,
-} auxtrace_snapshot_state = AUXTRACE_SNAPSHOT_OFF;
-
-static inline void
-auxtrace_snapshot_on(void)
-{
-	auxtrace_snapshot_state = AUXTRACE_SNAPSHOT_DISABLED;
-}
-
-static inline void
-auxtrace_snapshot_enable(void)
-{
-	if (auxtrace_snapshot_state == AUXTRACE_SNAPSHOT_OFF)
-		return;
-	auxtrace_snapshot_state = AUXTRACE_SNAPSHOT_ENABLED;
-}
-
-static inline void
-auxtrace_snapshot_disable(void)
-{
-	if (auxtrace_snapshot_state == AUXTRACE_SNAPSHOT_OFF)
-		return;
-	auxtrace_snapshot_state = AUXTRACE_SNAPSHOT_DISABLED;
-}
-
-static inline bool
-auxtrace_snapshot_is_enabled(void)
-{
-	if (auxtrace_snapshot_state == AUXTRACE_SNAPSHOT_OFF)
-		return false;
-	return auxtrace_snapshot_state == AUXTRACE_SNAPSHOT_ENABLED;
-}
-
-static volatile int auxtrace_snapshot_err;
 static volatile int auxtrace_record__snapshot_started;
+static DEFINE_TRIGGER(auxtrace_snapshot_trigger);
+static DEFINE_TRIGGER(switch_output_trigger);
 
 static void sig_handler(int sig)
 {
@@ -282,11 +249,12 @@ static void record__read_auxtrace_snapshot(struct record *rec)
 {
 	pr_debug("Recording AUX area tracing snapshot\n");
 	if (record__auxtrace_read_snapshot_all(rec) < 0) {
-		auxtrace_snapshot_err = -1;
+		trigger_error(&auxtrace_snapshot_trigger);
 	} else {
-		auxtrace_snapshot_err = auxtrace_record__snapshot_finish(rec->itr);
-		if (!auxtrace_snapshot_err)
-			auxtrace_snapshot_enable();
+		if (auxtrace_record__snapshot_finish(rec->itr))
+			trigger_error(&auxtrace_snapshot_trigger);
+		else
+			trigger_ready(&auxtrace_snapshot_trigger);
 	}
 }
 
@@ -532,6 +500,25 @@ record__finish_output(struct record *rec)
 	return;
 }
 
+static int record__synthesize_workload(struct record *rec)
+{
+	struct {
+		struct thread_map map;
+		struct thread_map_data map_data;
+	} thread_map;
+
+	thread_map.map.nr = 1;
+	thread_map.map.map[0].pid = rec->evlist->workload.pid;
+	thread_map.map.map[0].comm = NULL;
+	return perf_event__synthesize_thread_map(&rec->tool, &thread_map.map,
+						 process_synthesized_event,
+						 &rec->session->machines.host,
+						 rec->opts.sample_address,
+						 rec->opts.proc_map_timeout);
+}
+
+static int record__synthesize(struct record *rec);
+
 static int
 record__switch_output(struct record *rec, bool at_exit)
 {
@@ -560,6 +547,23 @@ record__switch_output(struct record *rec, bool at_exit)
 	if (!quiet)
 		fprintf(stderr, "[ perf record: Dump %s.%s ]\n",
 			file->path, timestamp);
+
+	/* Output tracking events */
+	if (!at_exit) {
+		record__synthesize(rec);
+
+		/*
+		 * In 'perf record --switch-output' without -a,
+		 * record__synthesize() in record__switch_output() won't
+		 * generate tracking events because there's no thread_map
+		 * in evlist. Which causes newly created perf.data doesn't
+		 * contain map and comm information.
+		 * Create a fake thread_map and directly call
+		 * perf_event__synthesize_thread_map() for those events.
+		 */
+		if (target__none(&rec->opts.target))
+			record__synthesize_workload(rec);
+	}
 	return fd;
 }
 
@@ -684,9 +688,12 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 	signal(SIGINT, sig_handler);
 	signal(SIGTERM, sig_handler);
 
-	if (rec->opts.auxtrace_snapshot_mode) {
+	if (rec->opts.auxtrace_snapshot_mode || rec->switch_output) {
 		signal(SIGUSR2, snapshot_sig_handler);
-		auxtrace_snapshot_on();
+		if (rec->opts.auxtrace_snapshot_mode)
+			trigger_on(&auxtrace_snapshot_trigger);
+		if (rec->switch_output)
+			trigger_on(&switch_output_trigger);
 	} else {
 		signal(SIGUSR2, SIG_IGN);
 	}
@@ -815,27 +822,45 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 		perf_evlist__enable(rec->evlist);
 	}
 
-	auxtrace_snapshot_enable();
+	trigger_ready(&auxtrace_snapshot_trigger);
+	trigger_ready(&switch_output_trigger);
 	for (;;) {
 		unsigned long long hits = rec->samples;
 
 		if (record__mmap_read_all(rec) < 0) {
-			auxtrace_snapshot_disable();
+			trigger_error(&auxtrace_snapshot_trigger);
+			trigger_error(&switch_output_trigger);
 			err = -1;
 			goto out_child;
 		}
 
 		if (auxtrace_record__snapshot_started) {
 			auxtrace_record__snapshot_started = 0;
-			if (!auxtrace_snapshot_err)
+			if (!trigger_is_error(&auxtrace_snapshot_trigger))
 				record__read_auxtrace_snapshot(rec);
-			if (auxtrace_snapshot_err) {
+			if (trigger_is_error(&auxtrace_snapshot_trigger)) {
 				pr_err("AUX area tracing snapshot failed\n");
 				err = -1;
 				goto out_child;
 			}
 		}
 
+		if (trigger_is_hit(&switch_output_trigger)) {
+			trigger_ready(&switch_output_trigger);
+
+			if (!quiet)
+				fprintf(stderr, "[ perf record: dump data: Woken up %ld times ]\n",
+					waking);
+			waking = 0;
+			fd = record__switch_output(rec, false);
+			if (fd < 0) {
+				pr_err("Failed to switch to new file\n");
+				trigger_error(&switch_output_trigger);
+				err = fd;
+				goto out_child;
+			}
+		}
+
 		if (hits == rec->samples) {
 			if (done || draining)
 				break;
@@ -858,12 +883,13 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 		 * disable events in this case.
 		 */
 		if (done && !disabled && !target__none(&opts->target)) {
-			auxtrace_snapshot_disable();
+			trigger_off(&auxtrace_snapshot_trigger);
 			perf_evlist__disable(rec->evlist);
 			disabled = true;
 		}
 	}
-	auxtrace_snapshot_disable();
+	trigger_off(&auxtrace_snapshot_trigger);
+	trigger_off(&switch_output_trigger);
 
 	if (forks && workload_exec_errno) {
 		char msg[STRERR_BUFSIZE];
@@ -1297,6 +1323,8 @@ struct option __record_options[] = {
 		    "Record build-id of all DSOs regardless of hits"),
 	OPT_BOOLEAN(0, "timestamp-filename", &record.timestamp_filename,
 		    "append timestamp to output filename"),
+	OPT_BOOLEAN(0, "switch-output", &record.switch_output,
+		    "Switch output when receive SIGUSR2"),
 	OPT_END()
 };
 
@@ -1352,6 +1380,9 @@ int cmd_record(int argc, const char **argv, const char *prefix __maybe_unused)
 		return -EINVAL;
 	}
 
+	if (rec->switch_output)
+		rec->timestamp_filename = true;
+
 	if (!rec->itr) {
 		rec->itr = auxtrace_record__init(rec->evlist, &err);
 		if (err)
@@ -1385,8 +1416,36 @@ int cmd_record(int argc, const char **argv, const char *prefix __maybe_unused)
 "If some relocation was applied (e.g. kexec) symbols may be misresolved\n"
 "even with a suitable vmlinux or kallsyms file.\n\n");
 
-	if (rec->no_buildid_cache || rec->no_buildid)
+	if (rec->no_buildid_cache || rec->no_buildid) {
 		disable_buildid_cache();
+	} else if (rec->switch_output) {
+		/*
+		 * In 'perf record --switch-output', disable buildid
+		 * generation by default to reduce data file switching
+		 * overhead. Still generate buildid if they are required
+		 * explicitly using
+		 *
+		 *  perf record --signal-trigger --no-no-buildid \
+		 *              --no-no-buildid-cache
+		 *
+		 * Following code equals to:
+		 *
+		 * if ((rec->no_buildid || !rec->no_buildid_set) &&
+		 *     (rec->no_buildid_cache || !rec->no_buildid_cache_set))
+		 *         disable_buildid_cache();
+		 */
+		bool disable = true;
+
+		if (rec->no_buildid_set && !rec->no_buildid)
+			disable = false;
+		if (rec->no_buildid_cache_set && !rec->no_buildid_cache)
+			disable = false;
+		if (disable) {
+			rec->no_buildid = true;
+			rec->no_buildid_cache = true;
+			disable_buildid_cache();
+		}
+	}
 
 	if (rec->evlist->nr_entries == 0 &&
 	    perf_evlist__add_default(rec->evlist) < 0) {
@@ -1445,9 +1504,13 @@ int cmd_record(int argc, const char **argv, const char *prefix __maybe_unused)
 
 static void snapshot_sig_handler(int sig __maybe_unused)
 {
-	if (!auxtrace_snapshot_is_enabled())
-		return;
-	auxtrace_snapshot_disable();
-	auxtrace_snapshot_err = auxtrace_record__snapshot_start(record.itr);
-	auxtrace_record__snapshot_started = 1;
+	if (trigger_is_ready(&auxtrace_snapshot_trigger)) {
+		trigger_hit(&auxtrace_snapshot_trigger);
+		auxtrace_record__snapshot_started = 1;
+		if (auxtrace_record__snapshot_start(record.itr))
+			trigger_error(&auxtrace_snapshot_trigger);
+	}
+
+	if (trigger_is_ready(&switch_output_trigger))
+		trigger_hit(&switch_output_trigger);
 }