Re: [UDEV, PATCH] Add profiling support to Makefile

[Michael Buesch <mbuesch@freenet.de>]

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Quoting Greg KH <greg@kroah.com>:
> On Sun, Feb 13, 2005 at 05:16:51PM +0100, Michael Buesch wrote:
> > Hi,
> > 
> > This patch adds an option to the Makefile to enable
> > profiling. Profiling is only enabled, when not building
> > against klibc, as klibc lacks support for mcount().
> > 
> > Please apply. Thanks.
> 
> You forgot to update the documentation about this option, so I'll hold
> off till you redo that :)

Oops. :O Here it is.

> Also, what has profiling information helped you out with in udev?  Found
> anything interesting?  Or are you just using it for coverage analysis
> (which is a flawed thing, but that's another topic...)

I did not do much testing, yet, because of missing time.
But I will do that.
My first testrun showed that the namedev matchrule function and the udevdb
are the slowest parts of the whole executable. So maybe there's some
optimization possible. But I'll look closer at it later.

> thanks,
> 
> greg k-h
> 
> 

-- 
Regards Michael Buesch  [ http://www.tuxsoft.de.vu ]



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===== README 1.15 vs edited =====
--- 1.15/README	2004-10-06 00:51:23 +02:00
+++ edited/README	2005-02-15 09:40:07 +01:00
@@ -50,6 +50,13 @@
 	DEBUG
 		if set to 'true', debugging messages will be sent to the syslog
 		as udev is run.  Default value is 'false'.
+	PROFILE
+		if set to 'true', additional profiling code is generated by gcc.
+		Every run of any udev executable will generate the gmon.out file,
+		which can be examined by tools like gprof / kprof and so on.
+		Klibc does NOT support profiling. Profiling is automatically
+		disabled if USE_KLIBC=true.
+		Default value is 'false'.
 	KERNEL_DIR
 		If this is not set it will default to /lib/modules/`uname -r`/build
 		This is used if USE_KLIBC=true to find the kernel include
===== Makefile 1.232 vs edited =====
--- 1.232/Makefile	2005-02-11 20:55:00 +01:00
+++ edited/Makefile	2005-02-13 17:15:25 +01:00
@@ -25,6 +25,12 @@
 # Leave this set to `false' for production use.
 DEBUG = false
 
+# Set the following to 'true' to let gcc generate
+# additional profiling code.
+# Profiling is NOT supported by klibc and disabled
+# automatically if USE_KLIBC=true
+PROFILE = false
+
 # Set this to compile with Security-Enhanced Linux support.
 USE_SELINUX = false
 
@@ -162,6 +168,10 @@
 	CFLAGS  += -DLOG
 endif
 
+ifeq ($(strip $(PROFILE)),true)
+	PROFILE_FLAGS = -pg -fno-omit-frame-pointer
+endif
+
 # if DEBUG is enabled, then we do not strip or optimize
 ifeq ($(strip $(DEBUG)),true)
 	CFLAGS  += -O1 -g -DDEBUG -D_GNU_SOURCE
@@ -185,6 +195,8 @@
 	# arch specific objects
 	ARCH_LIB_OBJS =	 $(KLIBC_DIR)/libc.a
 
+	# profiling is not supported by klibc (missing mcount() function)
+	PROFILE_FLAGS =
 
 	CRT0 = $(KLIBC_DIR)/crt0.o
 	LIBC = $(ARCH_LIB_OBJS) $(LIB_OBJS) $(CRT0)
@@ -218,6 +230,9 @@
 	LIB_OBJS = -lc
 	LDFLAGS =
 endif
+
+CFLAGS += $(PROFILE_FLAGS)
+LIB_OBJS += $(PROFILE_FLAGS)
 
 ifeq ($(strip $(USE_SELINUX)),true)
 	UDEV_OBJS += udev_selinux.o

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