From: Ingo Oeser <ioe-lkml@axxeo.de>
To: Linus Torvalds <torvalds@osdl.org>
Cc: linux@horizon.com, Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Make pipe data structure be a circular list of pages, rather
Date: Thu, 13 Jan 2005 22:46:37 +0100 [thread overview]
Message-ID: <200501132246.37289.ioe-lkml@axxeo.de> (raw)
In-Reply-To: <Pine.LNX.4.58.0501081018271.2386@ppc970.osdl.org>
Hi,
Linus Torvalds wrote:
> None of the pipes would do anything on their own - they aren't "actors".
> They'd be purely buffers. So if you want to have an asynchronous
> long-running "tee()/copy()/peek()", you'd have a thread that does that for
> you.
Hmm, that's a pity, because it makes hardware support more difficult.
I thought you might consider an system call, which "wires up" fds.
Imagine a device fd, which gets lots of measuring data, wired through a
DSP pipe, spliced to realtime display fd and file storage fd.
How many buffers do you like to use here? How much unnecessary copies
are made by the CPU?
Any realtime mass data processing needing hardware support could benefit
from "active" pipes, where either end could be drivers "knowing each other"
and deciding to rather route the IO in hardware, avoiding to go through the
overworked memory bus and CPU.
This kind of "wire me up to my next chip" is needed quite often in the
embedded world, where power matters and special purpose chips or even
DSPs rule. Every chipset vendor does its own libraries there for now,
but a more generic approach might be better.
What do you think?
Regards
Ingo Oeser
next prev parent reply other threads:[~2005-01-13 21:51 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-01-08 8:25 Make pipe data structure be a circular list of pages, rather linux
2005-01-08 18:41 ` Linus Torvalds
2005-01-08 21:47 ` Alan Cox
2005-01-13 21:46 ` Ingo Oeser [this message]
2005-01-13 22:32 ` Linus Torvalds
2005-01-14 21:03 ` Ingo Oeser
2005-01-14 21:29 ` Linus Torvalds
2005-01-14 22:12 ` Ingo Oeser
2005-01-14 22:44 ` Linus Torvalds
2005-01-14 23:34 ` Ingo Oeser
2005-01-15 0:16 ` Linus Torvalds
2005-01-16 2:59 ` Linus Torvalds
2005-01-17 16:03 ` Ingo Oeser
2005-01-19 21:12 ` Make pipe data structure be a circular list of pages, rather than linux
2005-01-20 2:06 ` Robert White
2005-01-15 23:42 Make pipe data structure be a circular list of pages, rather linux
2005-01-15 22:55 ` Alan Cox
2005-01-16 0:12 ` Linus Torvalds
2005-01-16 2:02 ` Miquel van Smoorenburg
2005-01-16 2:06 ` Jeff Garzik
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