Re: [PATCH 4/6] trace: Replace seq_printf by simpler equivalents

From: Steven Rostedt
Date: Wed Nov 05 2014 - 19:38:26 EST


On Wed, 05 Nov 2014 14:51:48 -0800
Joe Perches <joe@xxxxxxxxxxx> wrote:

> On Wed, 2014-11-05 at 17:34 -0500, Steven Rostedt wrote:
> > On Fri, 12 Sep 2014 11:25:52 +0200 Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx> wrote:
> > > Using seq_printf to print a simple string or a single character is a
> > > lot more expensive than it needs to be, since seq_puts and seq_putc
> > > exist.
> []
> > > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> []
> > @@ -556,13 +556,13 @@ static int function_stat_cmp(void *p1, void *p2)
> > > static int function_stat_headers(struct seq_file *m)
> > > {
> > > #ifdef CONFIG_FUNCTION_GRAPH_TRACER
> > > - seq_printf(m, " Function "
> > > - "Hit Time Avg s^2\n"
> > > - " -------- "
> > > - "--- ---- --- ---\n");
> > > + seq_puts(m,
> > > + " Function " "Hit Time Avg s^2\n"
> > > + " -------- " "--- ---- --- ---\n");
> >
> > Please keep the original format. I know that it's considered bad form
> > to split strings like this, but I consider this one of the exceptions
> > to the rule.
>
> Why is that?
>
> btw: when the strings fragments are put on the same line,
> it's nicer to take out the intermediate joining " " bits too.
>
> I'd've probably used 2 seq_puts calls like:
>
> seq_puts(m, " Function Hit Time Avg s^2\n");
> seq_puts(m, " -------- --- ---- --- ---\n");
>

In this case it's just that I hate that big white space followed by
content.

Maybe I'll change my mind in the future, but for now, I'd rather just
leave it as is.

-- Steve


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