Subject: [patch] enhance initcall_debug, measure latency
From: Ingo Molnar <mingo@elte.hu>
enhance the initcall_debug boot option:
- measure the time the initcall took to execute and report
it in units of milliseconds.
- show the return code of initcalls (useful to see failures and
to make sure that an initcall hung)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
init/main.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
Index: linux/init/main.c
===================================================================
--- linux.orig/init/main.c
+++ linux/init/main.c
@@ -685,6 +685,7 @@ static void __init do_initcalls(void)
int count = preempt_count();
for (call = __initcall_start; call < __initcall_end; call++) {
+ ktime_t t0, t1, delta;
char *msg = NULL;
char msgbuf[40];
int result;
@@ -694,10 +695,26 @@ static void __init do_initcalls(void)
print_fn_descriptor_symbol(": %s()",
(unsigned long) *call);
printk("\n");
+ t0 = ktime_get();
}
result = (*call)();
+ if (initcall_debug) {
+ t1 = ktime_get();
+ delta = ktime_sub(t1, t0);
+
+ printk("initcall 0x%p", *call);
+ print_fn_descriptor_symbol(": %s()",
+ (unsigned long) *call);
+ printk(" returned %d.\n", result);
+
+ printk("initcall 0x%p ran for %Ld msecs: ",
+ *call, delta.tv64 >> 20);
+ print_fn_descriptor_symbol("%s()\n",
+ (unsigned long) *call);
+ }
+
if (result && result != -ENODEV && initcall_debug) {
sprintf(msgbuf, "error code %d", result);
msg = msgbuf;
-
