tracing/fastboot: add better resolution to initcall debug/tracing

Change the time resolution for initcall_debug to microseconds, from
milliseconds.  This is handy to determine which initcalls you want to work
on for faster booting.

One one of my test machines, over 90% of the initcalls are less than a
millisecond and (without this patch) these are all reported as 0 msecs.
Working on the 900 us ones is more important than the 4 us ones.

With 'quiet' on the kernel command line, this adds no significant overhead
to kernel boot time.

Signed-off-by: Tim Bird <tim.bird@am.sony.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 4 insertions, 4 deletions

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 5812dba4ee24..a3d46151be19 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -215,9 +215,9 @@ ftrace_init_module(unsigned long *start, unsigned long *end) { }
 
 struct boot_trace {
         pid_t                   caller;
-        char                    func[KSYM_NAME_LEN];
+        char                    func[KSYM_NAME_LEN];
         int                     result;
-        unsigned long long      duration;
+        unsigned long long      duration;               /* usecs */
         ktime_t                 calltime;
         ktime_t                 rettime;
 };
diff --git a/init/main.c b/init/main.c
index e7939de80f3e..b2e7ff4a5349 100644
--- a/init/main.c
+++ b/init/main.c
@@ -721,8 +721,8 @@ int do_one_initcall(initcall_t fn)
         if (initcall_debug) {
                 it.rettime = ktime_get();
                 delta = ktime_sub(it.rettime, it.calltime);
-                it.duration = (unsigned long long) delta.tv64 >> 20;
-                printk("initcall %pF returned %d after %Ld msecs\n", fn,
+                it.duration = (unsigned long long) delta.tv64 >> 10;
+                printk("initcall %pF returned %d after %Ld usecs\n", fn,
                         it.result, it.duration);
                 trace_boot(&it, fn);
         }