Subject: Re: Efficient IPC mechanism on Linux
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Luca Veraldi <luca.veraldi@katamail.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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Date: Wed, 10 Sep 2003 00:11:57 +0100
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On Maw, 2003-09-09 at 22:57, Luca Veraldi wrote:
> Also. The central point is not to have10 instead of 50 assembler lines
> in the primitives. The central point is to implement communication
> primitives
> that do not require physical copying of the messages being sent and
> received.

The question (for smaller messages) is whether this is a win or not.
While the data fits in L1 cache the copy is close to free compared
with context switching and TLB overhead

> We have 2 process communicating over a channel in a pipeline fashion.
> A writes some information in a buffer and sends it to B.
> B receives and reads.
> This for 1000 times.
> Times reported are average time.

Ok - from you rexample I couldnt tell if B then touches each byte of
data as well as having it appear in its address space.

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