From: davidsen@tmr.com (bill davidsen)
To: linux-kernel@vger.kernel.org
Subject: Re: Can we kill f inb_p, outb_p and other random I/O on port 0x80, in 2.6?
Date: 23 Sep 2003 18:17:16 GMT [thread overview]
Message-ID: <bkq2nc$erb$1@gatekeeper.tmr.com> (raw)
In-Reply-To: 20030922182808.GA28372@mail.jlokier.co.uk
In article <20030922182808.GA28372@mail.jlokier.co.uk>,
Jamie Lokier <jamie@shareable.org> wrote:
| Arjan van de Ven wrote:
| > The first person to complain about the extra branch miss in udelay for
| > this will get laughed at by me ;)
|
| udelay(1) is too slow on a 386 even without the branch miss.
|
| If you think I/O operations are infinitely slower than other
| instructions, please explain why there is asm-optimised I/O code in
| asm-i386/floppy.h.
|
| :)
The choices are:
1 - there really were some old crappy chips which were both slow and
timing sensitive
2 - someone thought that would optimize access
3 - gcc of the time generated bad code if you didn't
--
bill davidsen <davidsen@tmr.com>
CTO, TMR Associates, Inc
Doing interesting things with little computers since 1979.
next prev parent reply other threads:[~2003-09-23 18:26 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-09-22 0:27 Can we kill f inb_p, outb_p and other random I/O on port 0x80, in 2.6? Eric W. Biederman
2003-09-22 11:22 ` Alan Cox
2003-09-22 16:26 ` Jamie Lokier
2003-09-22 16:33 ` Alan Cox
2003-09-22 17:11 ` Arjan van de Ven
2003-09-22 18:28 ` Jamie Lokier
2003-09-22 19:09 ` Eric W. Biederman
2003-09-22 19:27 ` Arjan van de Ven
2003-09-22 21:46 ` Jamie Lokier
2003-09-23 18:17 ` bill davidsen [this message]
2003-09-22 18:58 ` Eric W. Biederman
2003-09-22 19:19 ` Jamie Lokier
2003-09-23 0:09 ` Alan Cox
2003-09-23 18:20 ` bill davidsen
2003-09-22 19:00 ` Jamie Lokier
2003-09-22 20:05 ` Eric W. Biederman
2003-09-23 18:31 ` bill davidsen
2003-09-23 0:13 ` Alan Cox
[not found] <20030922153651.16497.qmail@science.horizon.com>
2003-09-22 18:35 ` Eric W. Biederman
2003-09-22 21:54 ` Jamie Lokier
2003-09-23 18:41 ` bill davidsen
2003-09-24 17:43 ` Linus Torvalds
-- strict thread matches above, loose matches on Subject: below --
2003-09-22 20:03 John Bradford
2003-09-22 21:37 ` Jamie Lokier
2003-09-22 21:42 ` Arjan van de Ven
2003-09-23 0:16 ` Alan Cox
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