From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Fulghum Subject: Re: [Bug #14388] keyboard under X with 2.6.31 Date: Tue, 13 Oct 2009 10:33:00 -0500 Message-ID: <1255447980.3898.3.camel@x2.microgate.com> References: <56acieJJ2fF.A.nEB.Hzl0KB@chimera> <87ljjgfcbu.fsf@spindle.srvr.nix> <20091013113232.384b2432@lxorguk.ukuu.org.uk> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: kernel-testers-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Linus Torvalds Cc: Alan Cox , Nix , "Justin P. Mattock" , "Rafael J. Wysocki" , Linux Kernel Mailing List , Kernel Testers List , Boyan , Dmitry Torokhov , Ed Tomlinson , "=?ISO-8859-1?Q?Fr=E9d=E9ric?= L. W. Meunier" , OGAWA Hirofumi On Tue, 2009-10-13 at 07:39 -0700, Linus Torvalds wrote: > It's not a f*cking performance tweak, and you're ludicrous to claim it is. > It's pointless, and it's making the code _slower_ rather than faster. > > Lookie here, Alan - the common sequence is crap like this: > > tty_buffer_request_room(tty, buf->size); > tty_insert_flip_string(tty, buf->base, buf->size); The performance tweak of tty_prepare_xxx is that you fill the tty_buffer directly instead of writing data first to a staging buffer and then calling tty_insert_flip_string, which just copies from the staging buffer to the tty_buffer. So it saves a copy operation. -- Paul Fulghum Microgate Systems, Ltd