Backport time tracking fix from NewOS:

thread code now properly traces time spent in user vs kernel mode. The code was
just plain broken before
http://www.newos.org/cgi-bin/perfbrowse.perl?@describe+1704


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@2599 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/kernel/thread_types.h

@@ -44,6 +44,10 @@ enum team_state {
 	TEAM_STATE_DEATH	// being killed
 };
 
+enum {
+	KERNEL_TIME,
+	USER_TIME
+};
 
 #define THREAD_RETURN_EXIT			0x1
 #define THREAD_RETURN_INTERRUPTED	0x2
@@ -129,6 +133,7 @@ struct thread {
 	bigtime_t		user_time;
 	bigtime_t		kernel_time;
 	bigtime_t		last_time;
+	int				last_time_type;	// KERNEL_TIME or USER_TIME
 	
 	// architecture dependant section
 	struct arch_thread arch_info;

src/kernel/core/scheduler.c

@@ -129,9 +129,12 @@ context_switch(struct thread *fromThread, struct thread *toThread)
 {
 	bigtime_t now;
 
-	// track kernel time
+	// track kernel & user time
 	now = system_time();
+	if(fromThread->last_time_type == KERNEL_TIME)
 		fromThread->kernel_time += now - fromThread->last_time;
+	else
+		fromThread->user_time += now - fromThread->last_time;
 	toThread->last_time = now;
 
 	toThread->cpu = fromThread->cpu;

src/kernel/core/thread.c

@@ -187,6 +187,7 @@ create_thread_struct(const char *name)
 	t->user_time = 0;
 	t->kernel_time = 0;
 	t->last_time = 0;
+	t->last_time_type = KERNEL_TIME;
 	t->return_code = 0;
 	t->return_flags = 0;
 
@@ -248,7 +249,9 @@ _create_user_thread_kentry(void)
 
 	// a signal may have been delivered here
 //	thread_atkernel_exit();
+	// start tracking kernel & user time
 	thread->last_time = system_time();
+	thread->last_time_type = KERNEL_TIME;
 	thread->in_kernel = false;
 
 	// jump to the entry point in user space
@@ -268,7 +271,9 @@ _create_kernel_thread_kentry(void)
 	struct thread *thread = thread_get_current_thread();
 	int (*func)(void *args);
 
+	// start tracking kernel & user time
 	thread->last_time = system_time();
+	thread->last_time_type = KERNEL_TIME;
 
 	// call the entry function with the appropriate args
 	func = (void *)thread->entry;
@@ -905,6 +910,7 @@ thread_atkernel_entry(void)
 	now = system_time();
 	t->user_time += now - t->last_time;
 	t->last_time = now;
+	t->last_time_type = KERNEL_TIME;
 
 	t->in_kernel = true;
 
@@ -937,6 +943,7 @@ thread_atkernel_exit(void)
 	now = system_time();
 	t->kernel_time += now - t->last_time;
 	t->last_time = now;
+	t->last_time_type = USER_TIME;
 
 	RELEASE_THREAD_LOCK();
 	restore_interrupts(state);