[PATCH 0/2] [GIT PULL] tracing: updates

[PATCH 0/2] [GIT PULL] tracing: updates

[Steven Rostedt]

Ingo,

Please pull the latest tip/perf/core tree, which can be found at:

  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git
tip/perf/core


Steven Rostedt (1):
      tracing/events: Show real number in array fields

Wu Zhangjin (1):
      ftrace: Speed up recordmcount

----
 include/linux/ftrace_event.h |    4 ++++
 include/trace/ftrace.h       |   14 ++++++++++----
 kernel/trace/trace_events.c  |    6 ++++++
 kernel/trace/trace_export.c  |   14 ++++++++++----
 scripts/Makefile.build       |   13 +++++++++----
 5 files changed, 39 insertions(+), 12 deletions(-)

[PATCH 1/2] ftrace: Speed up recordmcount

[Steven Rostedt]

[-- Attachment #1: 0001-ftrace-Speed-up-recordmcount.patch --]
[-- Type: text/plain, Size: 2746 bytes --]

From: Wu Zhangjin <wuzhangjin@gmail.com>

cmd_record_mcount is used to locate the _mcount symbols in the object
files, only the files compiled with -pg has the _mcount symbol, so, it
is only needed for such files, but the current cmd_record_mcount is used
for all of the object files, so, we need to fix it and speed it up.

Since -pg may be removed by the method used in kernel/trace/Makefile:

ORIG_CFLAGS := $(KBUILD_CFLAGS)
KBUILD_CFLAGS = $(subst -pg,,$(ORIG_CFLAGS))

Or may be removed by the method used in arch/x86/kernel/Makefile:

CFLAGS_REMOVE_file.o = -pg

So, we must check the last variable stores the compiling flags, that is
c_flags(Please refer to cmd_cc_o_c and rule_cc_o_c defined in
scripts/Makefile.build) and since the CFLAGS_REMOVE_file.o is already
filtered in _c_flags(Please refer to scripts/Makefile.lib) and _c_flags
has less symbols, therefore, we only need to check _c_flags.

---------------
Changes from v1:

  o Don't touch Makefile for CONFIG_FTRACE_MCOUNT_RECORD is enough
  o Use _c_flags intead of KBUILD_CFLAGS to cover CONFIG_REMOVE_file.o = -pg
  (feedback from Steven Rostedt <rostedt@goodmis.org>)

Acked-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
LKML-Reference: <3dc8cddf022eb7024f9f2cf857529a15bee8999a.1288196498.git.wuzhangjin@gmail.com>

[ changed if [ .. == .. ] to if [ .. = .. ] to handle dash environments ]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 scripts/Makefile.build |   13 +++++++++----
 1 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 5ad25e1..4eb99ab 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -214,17 +214,22 @@ ifdef BUILD_C_RECORDMCOUNT
 # The empty.o file is created in the make process in order to determine
 #  the target endianness and word size. It is made before all other C
 #  files, including recordmcount.
-cmd_record_mcount = if [ $(@) != "scripts/mod/empty.o" ]; then			\
-			$(objtree)/scripts/recordmcount "$(@)";			\
-		    fi;
+sub_cmd_record_mcount =					\
+	if [ $(@) != "scripts/mod/empty.o" ]; then	\
+		$(objtree)/scripts/recordmcount "$(@)";	\
+	fi;
 else
-cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
+sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
 	"$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
 	"$(if $(CONFIG_64BIT),64,32)" \
 	"$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \
 	"$(LD)" "$(NM)" "$(RM)" "$(MV)" \
 	"$(if $(part-of-module),1,0)" "$(@)";
 endif
+cmd_record_mcount = 						\
+	if [ "$(findstring -pg,$(_c_flags))" = "-pg" ]; then	\
+		$(sub_cmd_record_mcount)			\
+	fi;
 endif
 
 define rule_cc_o_c
-- 
1.7.1

[PATCH 2/2] tracing/events: Show real number in array fields

[Steven Rostedt]

[-- Attachment #1: 0002-tracing-events-Show-real-number-in-array-fields.patch --]
[-- Type: text/plain, Size: 3992 bytes --]

From: Steven Rostedt <srostedt@redhat.com>

Currently we have in something like the sched_switch event:

  field:char prev_comm[TASK_COMM_LEN];	offset:12;	size:16;	signed:1;

When a userspace tool such as perf tries to parse this, the
TASK_COMM_LEN is meaningless. This is done because the TRACE_EVENT() macro
simply uses a #len to show the string of the length. When the length is
an enum, we get a string that means nothing for tools.

By adding a static buffer and a mutex to protect it, we can store the
string into that buffer with snprintf and show the actual number.
Now we get:

  field:char prev_comm[16];       offset:12;      size:16;        signed:1;

Something much more useful.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/linux/ftrace_event.h |    4 ++++
 include/trace/ftrace.h       |   14 ++++++++++----
 kernel/trace/trace_events.c  |    6 ++++++
 kernel/trace/trace_export.c  |   14 ++++++++++----
 4 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 725bf6b..47e3997 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -225,6 +225,10 @@ enum {
 	FILTER_PTR_STRING,
 };
 
+#define EVENT_STORAGE_SIZE 128
+extern struct mutex event_storage_mutex;
+extern char event_storage[EVENT_STORAGE_SIZE];
+
 extern int trace_event_raw_init(struct ftrace_event_call *call);
 extern int trace_define_field(struct ftrace_event_call *call, const char *type,
 			      const char *name, int offset, int size,
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index e718a91..e16610c 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -296,13 +296,19 @@ static struct trace_event_functions ftrace_event_type_funcs_##call = {	\
 
 #undef __array
 #define __array(type, item, len)					\
-	BUILD_BUG_ON(len > MAX_FILTER_STR_VAL);				\
-	ret = trace_define_field(event_call, #type "[" #len "]", #item,	\
+	do {								\
+		mutex_lock(&event_storage_mutex);			\
+		BUILD_BUG_ON(len > MAX_FILTER_STR_VAL);			\
+		snprintf(event_storage, sizeof(event_storage),		\
+			 "%s[%d]", #type, len);				\
+		ret = trace_define_field(event_call, event_storage, #item, \
 				 offsetof(typeof(field), item),		\
 				 sizeof(field.item),			\
 				 is_signed_type(type), FILTER_OTHER);	\
-	if (ret)							\
-		return ret;
+		mutex_unlock(&event_storage_mutex);			\
+		if (ret)						\
+			return ret;					\
+	} while (0);
 
 #undef __dynamic_array
 #define __dynamic_array(type, item, len)				       \
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 0725eea..35fde09 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -27,6 +27,12 @@
 
 DEFINE_MUTEX(event_mutex);
 
+DEFINE_MUTEX(event_storage_mutex);
+EXPORT_SYMBOL_GPL(event_storage_mutex);
+
+char event_storage[EVENT_STORAGE_SIZE];
+EXPORT_SYMBOL_GPL(event_storage);
+
 LIST_HEAD(ftrace_events);
 LIST_HEAD(ftrace_common_fields);
 
diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c
index 4ba44de..4b74d71 100644
--- a/kernel/trace/trace_export.c
+++ b/kernel/trace/trace_export.c
@@ -83,13 +83,19 @@ static void __always_unused ____ftrace_check_##name(void)	\
 
 #undef __array
 #define __array(type, item, len)					\
-	BUILD_BUG_ON(len > MAX_FILTER_STR_VAL);				\
-	ret = trace_define_field(event_call, #type "[" #len "]", #item,	\
+	do {								\
+		BUILD_BUG_ON(len > MAX_FILTER_STR_VAL);			\
+		mutex_lock(&event_storage_mutex);			\
+		snprintf(event_storage, sizeof(event_storage),		\
+			 "%s[%d]", #type, len);				\
+		ret = trace_define_field(event_call, event_storage, #item, \
 				 offsetof(typeof(field), item),		\
 				 sizeof(field.item),			\
 				 is_signed_type(type), FILTER_OTHER);	\
-	if (ret)							\
-		return ret;
+		mutex_unlock(&event_storage_mutex);			\
+		if (ret)						\
+			return ret;					\
+	} while (0);
 
 #undef __array_desc
 #define __array_desc(type, container, item, len)			\
-- 
1.7.1