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From: Andrew Morton <andrewm@uow.edu.au>
To: Linus Torvalds <torvalds@transmeta.com>
Cc: Andrea Arcangeli <andrea@suse.de>, Ingo Molnar <mingo@elte.hu>,
	Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: softirq bugs in pre2
Date: Tue, 12 Jun 2001 12:54:49 +1000	[thread overview]
Message-ID: <3B258479.472F5C91@uow.edu.au> (raw)
In-Reply-To: <20010611193703.S5468@athlon.random> <Pine.LNX.4.31.0106111207350.4452-100000@penguin.transmeta.com>

Linus Torvalds wrote:
> 
> On Mon, 11 Jun 2001, Andrea Arcangeli wrote:
> >
> > Since I mentioned the copy-user latency fixes (even if offtopic with the
> > above) this is the URL for trivial merging:
> 
> The copy-user latency fixes only make sense for out-of-line copies. If
> we're going to have a conditional function call to "schedule()", we do not
> want to inline the dang thing any more - we've just destroyed our register
> set etc anyway.

It's overkill.  This adds many hundreds of scheduling points
to the kernel, of which we need only five.  It makes more
sense to simply open-code those five.

- generic_file_read/write
- read /dev/zero, /dev/mem
- memcpy_to_iovec()

This will by no means provide a low-latency kernel, but it will
fix the most common causes of poor interactivity in normal
use.

Just doing generic_file_read/write would suffice, actually.

  parent reply	other threads:[~2001-06-12  3:03 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-06-11 17:37 softirq bugs in pre2 Andrea Arcangeli
2001-06-11 19:09 ` Linus Torvalds
2001-06-11 19:41   ` Andrea Arcangeli
2001-06-11 20:55   ` Alan Cox
2001-06-11 22:42   ` Gigabit Intel NIC? - Intel Gigabit Ethernet Pro/1000T Shawn Starr
2001-06-12 16:34     ` Alan Cox
2001-06-12 17:20       ` Riley Williams
2001-06-13 10:25         ` Ion Badulescu
2001-06-13 12:40           ` Ralf Baechle
2001-06-13 17:07             ` James Sutherland
2001-06-14 20:59           ` Riley Williams
2001-06-14 21:10             ` Jeff Garzik
2001-06-14 21:14             ` Matthew Jacob
2001-06-14 21:29             ` Alan Cox
2001-06-14 21:52               ` Matthew Dharm
2001-06-14 21:58                 ` Alan Cox
2001-06-14 22:03                 ` Matthew Jacob
2001-06-15  2:20             ` Shawn Starr
2001-06-12  2:54   ` Andrew Morton [this message]
2001-06-11 21:58 ` softirq bugs in pre2 Pavel Machek

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