Commit ca538f6b authored Oct 09, 2008 by Tim Bird Committed by Ingo Molnar Oct 14, 2008

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>

parent ad0a3b68

include/linux/ftrace.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -217,7 +217,7 @@ struct boot_trace {
		pid_t caller;
		char func[KSYM_NAME_LEN];
		int result;
		unsigned long long duration;
		unsigned long long duration; /* usecs */
		ktime_t calltime;
		ktime_t rettime;
		};

init/main.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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);
		}

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