Re: [RFC 13/13] Char: nozomi, cleanup read and write

Jiri Slaby
2007-11-10T22:04:53Z

On 11/10/2007 05:15 PM, Adrian Bunk wrote:
> On Fri, Nov 09, 2007 at 06:51:35PM -0500, Jiri Slaby wrote:
>> ...
>> --- a/drivers/char/nozomi.c
>> +++ b/drivers/char/nozomi.c
>> ...
>> - if (size_bytes - i == 2) {
>> + if (unlikely(size_bytes - i == 2)) {
>> ...
>
> Please don't add likely/unlikely in drivers unless it brings a
> measurable improvement.

Why? Anyway I think this is the case. The body of the then branch is executed at
most once, while the else branch each time but last. If you write/read 1002
bytes, it means 250:1. ...and it's invoked from interrupt too...

regards,
--
Jiri Slaby (jirislaby@gmail.com)
Faculty of Informatics, Masaryk University