perf report: Display user/kernel differentiator

Before:

    25.96%  copy_user_generic_string
    15.23%  two_op
    15.19%  one_op
     6.92%  enough_duration
     1.23%  alloc_pages_current
     1.14%  acpi_os_read_port
     1.08%  _spin_lock

After:

    25.96%  [k] copy_user_generic_string
    15.23%  [.] two_op
    15.19%  [.] one_op
     6.92%  [.] enough_duration
     1.23%  [k] alloc_pages_current
     1.14%  [k] acpi_os_read_port
     1.08%  [k] _spin_lock

The '[k]' differentiator is a quick clue that it's a kernel symbol,
without having to bring in the full dso column.
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Documentation/perf_counter/builtin-report.c

@@ -504,7 +504,7 @@ sort__comm_print(FILE *fp, struct hist_entry *self)
 }
 
 static struct sort_entry sort_comm = {
-	.header 	= "         Command",
+	.header		= "         Command",
 	.cmp		= sort__comm_cmp,
 	.collapse	= sort__comm_collapse,
 	.print		= sort__comm_print,
@@ -569,10 +569,12 @@ sort__sym_print(FILE *fp, struct hist_entry *self)
 	if (verbose)
 		ret += fprintf(fp, "%#018llx  ", (__u64)self->ip);
 
-	if (self->sym)
-		ret += fprintf(fp, "%s", self->sym->name);
-	else
+	if (self->sym) {
+		ret += fprintf(fp, "[%c] %s",
+			self->dso == kernel_dso ? 'k' : '.', self->sym->name);
+	} else {
 		ret += fprintf(fp, "%#016llx", (__u64)self->ip);
+	}
 
 	return ret;
 }
@@ -586,9 +588,9 @@ static struct sort_entry sort_sym = {
 static int sort__need_collapse = 0;
 
 struct sort_dimension {
-	char *name;
-	struct sort_entry *entry;
-	int taken;
+	char			*name;
+	struct sort_entry	*entry;
+	int			taken;
 };
 
 static struct sort_dimension sort_dimensions[] = {