profiling: dynamically enable readprofile at runtime
Way too often, I have a machine that exhibits some kind of crappy
behavior. The CPU looks wedged in the kernel or it is spending way too
much system time and I wonder what is responsible.
I try to run readprofile. But, of course, Ubuntu doesn't enable it by
default. Dang!
The reason we boot-time enable it is that it takes a big bufffer that we
generally can only bootmem alloc. But, does it hurt to at least try and
runtime-alloc it?
To use:
echo 2 > /sys/kernel/profile
Then run readprofile like normal.
This should fix the compile issue with allmodconfig. I've compile-tested
on a bunch more configs now including a few more architectures.
Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/profile.h b/include/linux/profile.h
index 7e70872..5700450 100644
--- a/include/linux/profile.h
+++ b/include/linux/profile.h
@@ -35,7 +35,9 @@
extern int prof_on __read_mostly;
/* init basic kernel profiler */
-void __init profile_init(void);
+int profile_init(void);
+int profile_setup(char *str);
+int create_proc_profile(void);
void profile_tick(int type);
/*
@@ -84,9 +86,9 @@
#define prof_on 0
-static inline void profile_init(void)
+static inline int profile_init(void)
{
- return;
+ return 0;
}
static inline void profile_tick(int type)