Re: [patch] fix printk format typo in boot ftracer.

From: Arjan van de Ven
Date: Sat Oct 04 2008 - 20:25:12 EST


On Sat, 4 Oct 2008 22:58:12 +0200
"FrÃdÃric Weisbecker" <fweisbec@xxxxxxxxx> wrote:

> > - ret = trace_seq_printf(s, "[%5ld.%06ld] initcall %s
> > "
> > + ret = trace_seq_printf(s, "[%5ld.%09ld] initcall %s
> > " "returned %d after %lld msecs\n",
> > rettime.tv_sec,
> > rettime.tv_nsec,
>
> I picked these formats from the printk.c time formatting. But you're
> right, 09 would give us the whole nano precision.

it's more than precision, it's correctness.

doing "0.%02i" will do
0.100 if you pass it 100 and
0.10 if you pass it 10

and most off the time, except the first 0.1 seconds, you'll be passing
it 9 digits, but the first 0.1 seconds.. the %06 will just give really
incorrect results.



--
Arjan van de Ven Intel Open Source Technology Centre
For development, discussion and tips for power savings,
visit http://www.lesswatts.org
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/