Re: [PATCH] fs: seq_file: optimize seq_pad()

[Dmitry Voytik]

On Wed, Sep 10, 2014 at 5:21 PM, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
> On Wed, Sep 10, 2014 at 01:20:19PM +0400, Dmitry Voytik wrote:
>> Use seq_putc() instead of seq_printf() in seq_pad() because the
>> former is faster.
>
> _Solitary_ seq_putc() is certainly going to be faster, but that loop...
> Do you have profiling results, or is it just an apriori "printf must
> be sloooowwww"?

My fail, sorry. The commit message is little bit wrong. I meant that simple
looping of seq_putc() is faster than seq_printf(). I haven't done profilings.
I just realized that seq_printf() is more complex than simple loop
with seq_putc()
(no need to decode format string as in vsnprintf(), etc).
If I resend the patch with the following commit message:

Use a simple loop with seq_putc() instead of seq_printf() in seq_pad() as
this approach is faster due to less complexity in terms of machine cycles.

Would be it Okay?
Thank you for reviewing.

-- 
Best Regards,
Dmitry Voytik.
voytikd@xxxxxxxxx
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