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 <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
LKML-Reference: <[e-mail]>
Signed-off-by: Ingo Molnar <[e-mail]>

tools/perf/Makefile

···
 	BASIC_CFLAGS += -DNO_LIBPERL
 else
 	ALL_LDFLAGS += $(PERL_EMBED_LDOPTS)
+	LIB_OBJS += scripts/perl/Perf-Trace-Util/Context.o
 endif
 
 ifdef NO_DEMANGLE
···
 util/trace-event-perl.o: util/trace-event-perl.c PERF-CFLAGS
 	$(QUIET_CC)$(CC) -o util/trace-event-perl.o -c $(ALL_CFLAGS) $(PERL_EMBED_CCOPTS) -Wno-redundant-decls -Wno-strict-prototypes  -Wno-unused-parameter $<
 
+scripts/perl/Perf-Trace-Util/Context.o: scripts/perl/Perf-Trace-Util/Context.c PERF-CFLAGS
+	$(QUIET_CC)$(CC) -o scripts/perl/Perf-Trace-Util/Context.o -c $(ALL_CFLAGS) $(PERL_EMBED_CCOPTS) -Wno-redundant-decls -Wno-strict-prototypes -Wno-unused-parameter -Wno-nested-externs $<
+
 perf-%$X: %.o $(PERFLIBS)
 	$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) $(LIBS)
 
···
 #	$(RM) configure
 
 clean:
-	$(RM) *.o */*.o $(LIB_FILE)
+	$(RM) *.o */*.o */*/*.o */*/*/*.o $(LIB_FILE)
 	$(RM) $(ALL_PROGRAMS) $(BUILT_INS) perf$X
 	$(RM) $(TEST_PROGRAMS)
 	$(RM) *.spec *.pyc *.pyo */*.pyc */*.pyo common-cmds.h TAGS tags cscope*

tools/perf/scripts/perl/Perf-Trace-Util/Context.c

···
+/*
+ * This file was generated automatically by ExtUtils::ParseXS version 2.18_02 from the
+ * contents of Context.xs. Do not edit this file, edit Context.xs instead.
+ *
+ *	ANY CHANGES MADE HERE WILL BE LOST! 
+ *
+ */
+
+#line 1 "Context.xs"
+/*
+ * Context.xs.  XS interfaces for perf trace.
+ *
+ * Copyright (C) 2009 Tom Zanussi <[e-mail]>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#include "EXTERN.h"
+#include "perl.h"
+#include "XSUB.h"
+#include "../../../util/trace-event-perl.h"
+
+#ifndef PERL_UNUSED_VAR
+#  define PERL_UNUSED_VAR(var) if (0) var = var
+#endif
+
+#line 41 "Context.c"
+
+XS(XS_Perf__Trace__Context_get_common_pc); /* prototype to pass -Wmissing-prototypes */
+XS(XS_Perf__Trace__Context_get_common_pc)
+{
+#ifdef dVAR
+    dVAR; dXSARGS;
+#else
+    dXSARGS;
+#endif
+    if (items != 1)
+       Perl_croak(aTHX_ "Usage: %s(%s)", "Perf::Trace::Context::get_common_pc", "context");
+    PERL_UNUSED_VAR(cv); /* -W */
+    {
+	struct scripting_context *	context = INT2PTR(struct scripting_context *,SvIV(ST(0)));
+	int	RETVAL;
+	dXSTARG;
+
+	RETVAL = get_common_pc(context);
+	XSprePUSH; PUSHi((IV)RETVAL);
+    }
+    XSRETURN(1);
+}
+
+
+XS(XS_Perf__Trace__Context_get_common_flags); /* prototype to pass -Wmissing-prototypes */
+XS(XS_Perf__Trace__Context_get_common_flags)
+{
+#ifdef dVAR
+    dVAR; dXSARGS;
+#else
+    dXSARGS;
+#endif
+    if (items != 1)
+       Perl_croak(aTHX_ "Usage: %s(%s)", "Perf::Trace::Context::get_common_flags", "context");
+    PERL_UNUSED_VAR(cv); /* -W */
+    {
+	struct scripting_context *	context = INT2PTR(struct scripting_context *,SvIV(ST(0)));
+	int	RETVAL;
+	dXSTARG;
+
+	RETVAL = get_common_flags(context);
+	XSprePUSH; PUSHi((IV)RETVAL);
+    }
+    XSRETURN(1);
+}
+
+
+XS(XS_Perf__Trace__Context_get_common_lock_depth); /* prototype to pass -Wmissing-prototypes */
+XS(XS_Perf__Trace__Context_get_common_lock_depth)
+{
+#ifdef dVAR
+    dVAR; dXSARGS;
+#else
+    dXSARGS;
+#endif
+    if (items != 1)
+       Perl_croak(aTHX_ "Usage: %s(%s)", "Perf::Trace::Context::get_common_lock_depth", "context");
+    PERL_UNUSED_VAR(cv); /* -W */
+    {
+	struct scripting_context *	context = INT2PTR(struct scripting_context *,SvIV(ST(0)));
+	int	RETVAL;
+	dXSTARG;
+
+	RETVAL = get_common_lock_depth(context);
+	XSprePUSH; PUSHi((IV)RETVAL);
+    }
+    XSRETURN(1);
+}
+
+#ifdef __cplusplus
+extern "C"
+#endif
+XS(boot_Perf__Trace__Context); /* prototype to pass -Wmissing-prototypes */
+XS(boot_Perf__Trace__Context)
+{
+#ifdef dVAR
+    dVAR; dXSARGS;
+#else
+    dXSARGS;
+#endif
+    const char* file = __FILE__;
+
+    PERL_UNUSED_VAR(cv); /* -W */
+    PERL_UNUSED_VAR(items); /* -W */
+    XS_VERSION_BOOTCHECK ;
+
+        newXSproto("Perf::Trace::Context::get_common_pc", XS_Perf__Trace__Context_get_common_pc, file, "$");
+        newXSproto("Perf::Trace::Context::get_common_flags", XS_Perf__Trace__Context_get_common_flags, file, "$");
+        newXSproto("Perf::Trace::Context::get_common_lock_depth", XS_Perf__Trace__Context_get_common_lock_depth, file, "$");
+    if (PL_unitcheckav)
+         call_list(PL_scopestack_ix, PL_unitcheckav);
+    XSRETURN_YES;
+}
+

tools/perf/scripts/perl/Perf-Trace-Util/Context.xs

···
+/*
+ * Context.xs.  XS interfaces for perf trace.
+ *
+ * Copyright (C) 2009 Tom Zanussi <[e-mail]>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#include "EXTERN.h"
+#include "perl.h"
+#include "XSUB.h"
+#include "../../../util/trace-event-perl.h"
+
+MODULE = Perf::Trace::Context		PACKAGE = Perf::Trace::Context
+PROTOTYPES: ENABLE
+
+int
+get_common_pc(context)
+	struct scripting_context * context
+
+int
+get_common_flags(context)
+	struct scripting_context * context
+
+int
+get_common_lock_depth(context)
+	struct scripting_context * context
+

tools/perf/scripts/perl/Perf-Trace-Util/Makefile.PL

···
 # See lib/ExtUtils/MakeMaker.pm for details of how to influence
 # the contents of the Makefile that is written.
 WriteMakefile(
-    NAME              => 'Perf::Trace::Util',
-    VERSION_FROM      => 'lib/Perf/Trace/Util.pm', # finds $VERSION
+    NAME              => 'Perf::Trace::Context',
+    VERSION_FROM      => 'lib/Perf/Trace/Context.pm', # finds $VERSION
     PREREQ_PM         => {}, # e.g., Module::Name => 1.1
     ($] >= 5.005 ?     ## Add these new keywords supported since 5.005
-      (ABSTRACT_FROM  => 'lib/Perf/Trace/Util.pm', # retrieve abstract from module
+      (ABSTRACT_FROM  => 'lib/Perf/Trace/Context.pm', # retrieve abstract from module
        AUTHOR         => 'Tom Zanussi <[e-mail]>') : ()),
+    LIBS              => [''], # e.g., '-lm'
+    DEFINE            => '-I ../..', # e.g., '-DHAVE_SOMETHING'
+    INC               => '-I.', # e.g., '-I. -I/usr/include/other'
+	# Un-comment this if you add C files to link with later:
+    OBJECT            => 'Context.o', # link all the C files too
 );

tools/perf/scripts/perl/Perf-Trace-Util/README

···
 
 This module contains utility functions for use with perf trace.
 
+Core.pm and Util.pm are pure Perl modules; Core.pm contains routines
+that the core perf support for Perl calls on and should always be
+'used', while Util.pm contains useful but optional utility functions
+that scripts may want to use.  Context.pm contains the Perl->C
+interface that allows scripts to access data in the embedding perf
+executable; scripts wishing to do that should 'use Context.pm'.
+
+The Perl->C perf interface is completely driven by Context.xs.  If you
+want to add new Perl functions that end up accessing C data in the
+perf executable, you add desciptions of the new functions here.
+scripting_context is a pointer to the perf data in the perf executable
+that you want to access - it's passed as the second parameter,
+$context, to all handler functions.
+
+After you do that:
+
+  perl Makefile.PL   # to create a Makefile for the next step
+  make               # to create Context.c
+
+  edit Context.c to add const to the char* file = __FILE__ line in
+  XS(boot_Perf__Trace__Context) to silence a warning/error.
+
+  You can delete the Makefile, object files and anything else that was
+  generated e.g. blib and shared library, etc, except for of course
+  Context.c
+
+  You should then be able to run the normal perf make as usual.
+
 INSTALLATION
 
 Building perf with perf trace Perl scripting should install this
···
 
 This module requires these other modules and libraries:
 
-  blah blah blah
+  None
 
 COPYRIGHT AND LICENCE
-
-Put the correct copyright and licence information here.
 
 Copyright (C) 2009 by Tom Zanussi <[e-mail]>
 
···
 Alternatively, this software may be distributed under the terms of the
 GNU General Public License ("GPL") version 2 as published by the Free
 Software Foundation.
-
-
 

tools/perf/scripts/perl/Perf-Trace-Util/lib/Perf/Trace/Context.pm

···
+package Perf::Trace::Context;
+
+use 5.010000;
+use strict;
+use warnings;
+
+require Exporter;
+
+our @ISA = qw(Exporter);
+
+our %EXPORT_TAGS = ( 'all' => [ qw(
+) ] );
+
+our @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } );
+
+our @EXPORT = qw(
+	common_pc common_flags common_lock_depth
+);
+
+our $VERSION = '0.01';
+
+require XSLoader;
+XSLoader::load('Perf::Trace::Context', $VERSION);
+
+1;
+__END__
+=head1 NAME
+
+Perf::Trace::Context - Perl extension for accessing functions in perf.
+
+=head1 SYNOPSIS
+
+  use Perf::Trace::Context;
+
+=head1 SEE ALSO
+
+Perf (trace) documentation
+
+=head1 AUTHOR
+
+Tom Zanussi, E<lt>[e-mail]<gt>
+
+=head1 COPYRIGHT AND LICENSE
+
+Copyright (C) 2009 by Tom Zanussi
+
+This library is free software; you can redistribute it and/or modify
+it under the same terms as Perl itself, either Perl version 5.10.0 or,
+at your option, any later version of Perl 5 you may have available.
+
+Alternatively, this software may be distributed under the terms of the
+GNU General Public License ("GPL") version 2 as published by the Free
+Software Foundation.
+
+=cut

tools/perf/scripts/perl/Perf-Trace-Util/lib/Perf/Trace/Core.pm

···
 our @EXPORT = qw(
 define_flag_field define_flag_value flag_str dump_flag_fields
 define_symbolic_field define_symbolic_value symbol_str dump_symbolic_fields
+trace_flag_str
 );
 
 our $VERSION = '0.01';
+
+my %trace_flags = (0x00 => "NONE",
+		   0x01 => "IRQS_OFF",
+		   0x02 => "IRQS_NOSUPPORT",
+		   0x04 => "NEED_RESCHED",
+		   0x08 => "HARDIRQ",
+		   0x10 => "SOFTIRQ");
+
+sub trace_flag_str
+{
+    my ($value) = @_;
+
+    my $string;
+
+    my $print_delim = 0;
+
+    foreach my $idx (sort {$a <=> $b} keys %trace_flags) {
+	if (!$value && !$idx) {
+	    $string .= "NONE";
+	    last;
+	}
+
+	if ($idx && ($value & $idx) == $idx) {
+	    if ($print_delim) {
+		$string .= " | ";
+	    }
+	    $string .= "$trace_flags{$idx}";
+	    $print_delim = 1;
+	    $value &= ~$idx;
+	}
+    }
+
+    return $string;
+}
 
 my %flag_fields;
 my %symbolic_fields;

tools/perf/scripts/perl/Perf-Trace-Util/typemap

···
+struct scripting_context * T_PTR

tools/perf/scripts/perl/check-perf-trace.pl

···
+# perf trace event handlers, generated by perf trace -g perl
+# (c) 2009, Tom Zanussi <[e-mail]>
+# 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);
+}

tools/perf/util/trace-event-parse.c

···
 			      "common_pid");
 }
 
-static int parse_common_pc(void *data)
+int parse_common_pc(void *data)
 {
 	static int pc_offset;
 	static int pc_size;
···
 			      "common_preempt_count");
 }
 
-static int parse_common_flags(void *data)
+int parse_common_flags(void *data)
 {
 	static int flags_offset;
 	static int flags_size;
···
 			      "common_flags");
 }
 
-static int parse_common_lock_depth(void *data)
+int parse_common_lock_depth(void *data)
 {
 	static int ld_offset;
 	static int ld_size;

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

···
 #include "trace-event.h"
 #include "trace-event-perl.h"
 
+void xs_init(pTHX);
+
+void boot_Perf__Trace__Context(pTHX_ CV *cv);
+void boot_DynaLoader(pTHX_ CV *cv);
+
+void xs_init(pTHX)
+{
+	const char *file = __FILE__;
+	dXSUB_SYS;
+
+	newXS("Perf::Trace::Context::bootstrap", boot_Perf__Trace__Context,
+	      file);
+	newXS("DynaLoader::boot_DynaLoader", boot_DynaLoader, file);
+}
+
 INTERP my_perl;
 
 #define FTRACE_MAX_EVENT				\
···
 	return event;
 }
 
+int get_common_pc(struct scripting_context *context)
+{
+	int pc;
+
+	pc = parse_common_pc(context->event_data);
+
+	return pc;
+}
+
+int get_common_flags(struct scripting_context *context)
+{
+	int flags;
+
+	flags = parse_common_flags(context->event_data);
+
+	return flags;
+}
+
+int get_common_lock_depth(struct scripting_context *context)
+{
+	int lock_depth;
+
+	lock_depth = parse_common_lock_depth(context->event_data);
+
+	return lock_depth;
+}
+
 static void perl_process_event(int cpu, void *data,
 			       int size __attribute((unused)),
 			       unsigned long long nsecs, char *comm)
···
 	}
 
 	PUTBACK;
+
 	if (get_cv(handler, 0))
 		call_pv(handler, G_SCALAR);
 	else if (get_cv("main::trace_unhandled", 0)) {
···
 	my_perl = perl_alloc();
 	perl_construct(my_perl);
 
-	if (perl_parse(my_perl, NULL, 2, (char **)command_line, (char **)NULL))
+	if (perl_parse(my_perl, xs_init, 2, (char **)command_line,
+		       (char **)NULL))
 		return -1;
 
 	perl_run(my_perl);

tools/perf/util/trace-event-perl.h

···
 #define perl_run(a)		(0)
 #define perl_destruct(a)	(0)
 #define perl_free(a)		(0)
+#define pTHX			void
+#define CV			void
+#define dXSUB_SYS
+#define pTHX_
+static inline void newXS(const char *a, void *b, const char *c) {}
 #else
 #include <EXTERN.h>
 #include <perl.h>
···
 struct scripting_context {
 	void *event_data;
 };
+
+int get_common_pc(struct scripting_context *context);
+int get_common_flags(struct scripting_context *context);
+int get_common_lock_depth(struct scripting_context *context);
 
 #endif /* __PERF_TRACE_EVENT_PERL_H */

tools/perf/util/trace-event.h

···
 int parse_header_page(char *buf, unsigned long size);
 int trace_parse_common_type(void *data);
 int trace_parse_common_pid(void *data);
+int parse_common_pc(void *data);
+int parse_common_flags(void *data);
+int parse_common_lock_depth(void *data);
 struct event *trace_find_event(int id);
 struct event *trace_find_next_event(struct event *event);
 unsigned long long read_size(void *ptr, int size);