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List:       linux-arm-kernel
Subject:    perfomance of copy_to/from_user
From:       Thomas =?iso-8859-1?q?W=F6ckinger?= <twc () sbox ! tugraz ! at>
Date:       2004-10-06 16:06:52
Message-ID: 200410061806.53286.twc () sbox ! tugraz ! at
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Hi!

I have some performance Problems using copy_to_user or copy_from_user. I can 
only transfer about 22,5 MB/s from or to userspace

I am using an Intel Xscale processor running on 500MHz pluged into idxp425 
development board. An DSP card (pluged into PCI slot) is writing directly 
into a 256K kernel space buffer.

the kernel version is 2.6.8.1

My first question is: can i speed up the copy_to/from_user?

if not, is it possible on an idxp425 board to access the whole memory 
directly, so that i can write to the userspace buffer without using the 
xscale.

i heard about dma_bounce buffer, but i am not sure if they are a solution form 
my problem.

thx Tom

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