perf trace: Add interface to access perf data from Perl handlers

The Perl scripting support for perf trace allows most of a trace
event's data to be accessed directly as handler arguments, but
not all of it e.g. the less common fields aren't passed in.  To
give scripts access to the other fields and/or any other data or
metadata in the main perf executable that might be useful, a way
to access the C data in perf from Perl is needed; this patch
uses the Perl XS facility to do it for the common_xxx event
fields not passed to handler functions.

Context.pm exports three functions to Perl scripts that access
fields for the current event by calling back into perf:
common_pc(), common_flags() and common_lock_depth().  Support
for common_flags() field values was added to Core.pm and a
script used to sanity check these and other basic scripting
features, check-perf-trace.pl, was also added.

Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: fweisbec@gmail.com
Cc: rostedt@goodmis.org
Cc: anton@samba.org
Cc: hch@infradead.org
LKML-Reference: <1259133352-23685-6-git-send-email-tzanussi@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 106 insertions, 0 deletions

diff --git a/tools/perf/scripts/perl/check-perf-trace.pl b/tools/perf/scripts/perl/check-perf-trace.pl
new file mode 100644
index 00000000000..4e7dc0a407a
--- /dev/null
+++ b/tools/perf/scripts/perl/check-perf-trace.pl
@@ -0,0 +1,106 @@
+# perf trace event handlers, generated by perf trace -g perl
+# (c) 2009, Tom Zanussi <tzanussi@gmail.com>
+# Licensed under the terms of the GNU GPL License version 2
+
+# This script tests basic functionality such as flag and symbol
+# strings, common_xxx() calls back into perf, begin, end, unhandled
+# events, etc.  Basically, if this script runs successfully and
+# displays expected results, perl scripting support should be ok.
+
+use lib "$ENV{'PERF_EXEC_PATH'}/scripts/perl/Perf-Trace-Util/lib";
+use lib "./Perf-Trace-Util/lib";
+use Perf::Trace::Core;
+use Perf::Trace::Context;
+use Perf::Trace::Util;
+
+sub trace_begin
+{
+    print "trace_begin\n";
+}
+
+sub trace_end
+{
+    print "trace_end\n";
+
+    print_unhandled();
+}
+
+sub irq::softirq_entry
+{
+	my ($event_name, $context, $common_cpu, $common_secs, $common_nsecs,
+	    $common_pid, $common_comm,
+	    $vec) = @_;
+
+	print_header($event_name, $common_cpu, $common_secs, $common_nsecs,
+		     $common_pid, $common_comm);
+
+	print_uncommon($context);
+
+	printf("vec=%s\n",
+	       symbol_str("irq::softirq_entry", "vec", $vec));
+}
+
+sub kmem::kmalloc
+{
+	my ($event_name, $context, $common_cpu, $common_secs, $common_nsecs,
+	    $common_pid, $common_comm,
+	    $call_site, $ptr, $bytes_req, $bytes_alloc,
+	    $gfp_flags) = @_;
+
+	print_header($event_name, $common_cpu, $common_secs, $common_nsecs,
+		     $common_pid, $common_comm);
+
+	print_uncommon($context);
+
+	printf("call_site=%p, ptr=%p, bytes_req=%u, bytes_alloc=%u, ".
+	       "gfp_flags=%s\n",
+	       $call_site, $ptr, $bytes_req, $bytes_alloc,
+
+	       flag_str("kmem::kmalloc", "gfp_flags", $gfp_flags));
+}
+
+# print trace fields not included in handler args
+sub print_uncommon
+{
+    my ($context) = @_;
+
+    printf("common_preempt_count=%d, common_flags=%s, common_lock_depth=%d, ",
+	   common_pc($context), trace_flag_str(common_flags($context)),
+	   common_lock_depth($context));
+
+}
+
+my %unhandled;
+
+sub print_unhandled
+{
+    if ((scalar keys %unhandled) == 0) {
+	return;
+    }
+
+    print "\nunhandled events:\n\n";
+
+    printf("%-40s  %10s\n", "event", "count");
+    printf("%-40s  %10s\n", "----------------------------------------",
+	   "-----------");
+
+    foreach my $event_name (keys %unhandled) {
+	printf("%-40s  %10d\n", $event_name, $unhandled{$event_name});
+    }
+}
+
+sub trace_unhandled
+{
+    my ($event_name, $context, $common_cpu, $common_secs, $common_nsecs,
+	$common_pid, $common_comm) = @_;
+
+    $unhandled{$event_name}++;
+}
+
+sub print_header
+{
+	my ($event_name, $cpu, $secs, $nsecs, $pid, $comm) = @_;
+
+	printf("%-20s %5u %05u.%09u %8u %-20s ",
+	       $event_name, $cpu, $secs, $nsecs, $pid, $comm);
+}