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

From: Ingo Molnar
Date: Sun Oct 05 2008 - 05:51:51 EST



* Arjan van de Ven <arjan@xxxxxxxxxxxxx> wrote:

> On Sat, 4 Oct 2008 22:58:12 +0200
> "Frédéric 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.

applied to tip/tracing/core, thanks!

Ingo
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