perf script: Add generic perl handler to process events

The current perf scripting facility only supports tracepoints. This
patch implements a generic perl handler to support other events than
tracepoints too.

This patch introduces a function process_event() that is called by perf
for each sample. The function is called with byte streams as arguments
containing information about the event, its attributes, the sample and
raw data. Perl's unpack() function can easily be used for byte decoding.
The following is the default implementation for process_event() that can
also be generated with perf script:

# Packed byte string args of process_event():
#
# $event: union perf_event util/event.h
# $attr: struct perf_event_attr linux/perf_event.h
# $sample: struct perf_sample util/event.h
# $raw_data: perf_sample->raw_data util/event.h

sub process_event
{
my ($event, $attr, $sample, $raw_data) = @_;

my @event = unpack("LSS", $event);
my @attr = unpack("LLQQQQQLLQQ", $attr);
my @sample = unpack("QLLQQQQQLL", $sample);
my @raw_data = unpack("C*", $raw_data);

use Data::Dumper;
print Dumper \@event, \@attr, \@sample, \@raw_data;
}

Cc: Ingo Molnar <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Stephane Eranian <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Robert Richter <[e-mail]>
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/scripting-engines/trace-event-perl.c

···
 #include "../thread.h"
 #include "../event.h"
 #include "../trace-event.h"
+#include "../evsel.h"
 
 #include <EXTERN.h>
 #include <perl.h>
···
 	return event;
 }
 
-static void perl_process_event(union perf_event *pevent __unused,
-			       struct perf_sample *sample,
-			       struct perf_evsel *evsel,
-			       struct machine *machine __unused,
-			       struct thread *thread)
+static void perl_process_tracepoint(union perf_event *pevent __unused,
+				    struct perf_sample *sample,
+				    struct perf_evsel *evsel,
+				    struct machine *machine __unused,
+				    struct thread *thread)
 {
 	struct format_field *field;
 	static char handler[256];
···
 	char *comm = thread->comm;
 
 	dSP;
+
+	if (evsel->attr.type != PERF_TYPE_TRACEPOINT)
+		return;
 
 	type = trace_parse_common_type(data);
 
···
 	PUTBACK;
 	FREETMPS;
 	LEAVE;
+}
+
+static void perl_process_event_generic(union perf_event *pevent __unused,
+				       struct perf_sample *sample,
+				       struct perf_evsel *evsel __unused,
+				       struct machine *machine __unused,
+				       struct thread *thread __unused)
+{
+	dSP;
+
+	if (!get_cv("process_event", 0))
+		return;
+
+	ENTER;
+	SAVETMPS;
+	PUSHMARK(SP);
+	XPUSHs(sv_2mortal(newSVpvn((const char *)pevent, pevent->header.size)));
+	XPUSHs(sv_2mortal(newSVpvn((const char *)&evsel->attr, sizeof(evsel->attr))));
+	XPUSHs(sv_2mortal(newSVpvn((const char *)sample, sizeof(*sample))));
+	XPUSHs(sv_2mortal(newSVpvn((const char *)sample->raw_data, sample->raw_size)));
+	PUTBACK;
+	call_pv("process_event", G_SCALAR);
+	SPAGAIN;
+	PUTBACK;
+	FREETMPS;
+	LEAVE;
+}
+
+static void perl_process_event(union perf_event *pevent,
+			       struct perf_sample *sample,
+			       struct perf_evsel *evsel,
+			       struct machine *machine,
+			       struct thread *thread)
+{
+	perl_process_tracepoint(pevent, sample, evsel, machine, thread);
+	perl_process_event_generic(pevent, sample, evsel, machine, thread);
 }
 
 static void run_start_sub(void)
···
 	fprintf(ofp, "sub print_header\n{\n"
 		"\tmy ($event_name, $cpu, $secs, $nsecs, $pid, $comm) = @_;\n\n"
 		"\tprintf(\"%%-20s %%5u %%05u.%%09u %%8u %%-20s \",\n\t       "
-		"$event_name, $cpu, $secs, $nsecs, $pid, $comm);\n}");
+		"$event_name, $cpu, $secs, $nsecs, $pid, $comm);\n}\n");
+
+	fprintf(ofp,
+		"\n# Packed byte string args of process_event():\n"
+		"#\n"
+		"# $event:\tunion perf_event\tutil/event.h\n"
+		"# $attr:\tstruct perf_event_attr\tlinux/perf_event.h\n"
+		"# $sample:\tstruct perf_sample\tutil/event.h\n"
+		"# $raw_data:\tperf_sample->raw_data\tutil/event.h\n"
+		"\n"
+		"sub process_event\n"
+		"{\n"
+		"\tmy ($event, $attr, $sample, $raw_data) = @_;\n"
+		"\n"
+		"\tmy @event\t= unpack(\"LSS\", $event);\n"
+		"\tmy @attr\t= unpack(\"LLQQQQQLLQQ\", $attr);\n"
+		"\tmy @sample\t= unpack(\"QLLQQQQQLL\", $sample);\n"
+		"\tmy @raw_data\t= unpack(\"C*\", $raw_data);\n"
+		"\n"
+		"\tuse Data::Dumper;\n"
+		"\tprint Dumper \\@event, \\@attr, \\@sample, \\@raw_data;\n"
+		"}\n");
 
 	fclose(ofp);