From: Jiri Slaby <jirislaby@gmail.com>
To: Adrian Bunk <bunk@kernel.org>
Cc: linux-kernel@vger.kernel.org, Frank Seidel <fseidel@suse.de>
Subject: Re: [RFC 13/13] Char: nozomi, cleanup read and write
Date: Sat, 10 Nov 2007 23:04:41 +0100 [thread overview]
Message-ID: <47362AF9.5080009@gmail.com> (raw)
In-Reply-To: <20071110161511.GA21669@stusta.de>
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
next prev parent reply other threads:[~2007-11-10 22:04 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-09 23:43 [RFC 1/13] Char: nozomi, remove unneded stuff Jiri Slaby
2007-11-09 23:44 ` [RFC 2/13] Char: nozomi, expand some functions Jiri Slaby
2007-11-10 15:41 ` Frank Seidel
2007-11-09 23:44 ` [RFC 3/13] Char: nozomi, fix fail paths Jiri Slaby
2007-11-10 15:41 ` Frank Seidel
2007-11-09 23:45 ` [RFC 4/13] Char: nozomi, tty index cleanup Jiri Slaby
2007-11-10 15:41 ` Frank Seidel
2007-11-10 15:50 ` Jiri Slaby
2007-11-09 23:46 ` [RFC 5/13] Char: nozomi, ioctls cleanup Jiri Slaby
2007-11-10 15:41 ` Frank Seidel
2007-11-09 23:46 ` [RFC 6/13] Char: nozomi, reorder and cleanup probe, remove Jiri Slaby
2007-11-10 15:42 ` Frank Seidel
2007-11-09 23:47 ` [RFC 7/13] Char: nozomi, remove struct irq Jiri Slaby
2007-11-10 15:42 ` Frank Seidel
2007-11-12 15:11 ` Frank Seidel
2007-11-09 23:48 ` [RFC 8/13] Char: nozomi, tty cleanup Jiri Slaby
2007-11-10 15:42 ` Frank Seidel
2007-11-12 18:43 ` Frank Seidel
2007-11-09 23:48 ` [RFC 9/13] Char: nozomi, lock cleanup Jiri Slaby
2007-11-10 15:42 ` Frank Seidel
2007-11-09 23:49 ` [RFC! 10/13] Char: nozomi, fix tty_flip_buffer_push Jiri Slaby
2007-11-10 15:43 ` Frank Seidel
2007-11-09 23:50 ` [RFC 11/13] Char: nozomi, remove unused includes Jiri Slaby
2007-11-10 15:43 ` Frank Seidel
2007-11-09 23:50 ` [RFC 12/13] Char: nozomi, remove void acc char2 char3 more mp mp.c mp.yy m1 nozomi2 proto rej slock1 casts Jiri Slaby
2007-11-10 15:43 ` Frank Seidel
2007-11-09 23:51 ` [RFC 13/13] Char: nozomi, cleanup read and write Jiri Slaby
2007-11-10 15:43 ` Frank Seidel
2007-11-10 16:15 ` Adrian Bunk
2007-11-10 22:04 ` Jiri Slaby [this message]
2007-11-11 2:37 ` Frank Seidel
2007-11-11 16:02 ` Frank Seidel
2007-11-12 7:54 ` Adrian Bunk
2007-11-12 9:43 ` Frank Seidel
2007-11-10 15:41 ` [RFC 1/13] Char: nozomi, remove unneded stuff Frank Seidel
2007-11-10 15:55 ` Jiri Slaby
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