Re: How to avoid data copies in a driver ?


On Wed, 14 May 2008, Francis Moreau wrote:

Hello,

I'd like to optimize my driver, which receives data through a fifo and gives
them to a user space application. In turns this application moves this data
into a file.

To avoid several useless copies, I'd like the application to pass to
the driver
a file descriptor (?) to the driver and then the driver can directly
move the
received data to that file.

Could anybody give me some example of such scheme ?

Thanks,
--
Francis
--

You memory-map the data. Impliment mmap() in your driver.
You can also impliment poll() { select() } so your
application knows when new data are available.

You cannot use a user-mode file-descriptor in the kernel.


Cheers,
*** Johnson
Penguin : Linux version 2.6.22.1 on an i686 machine (5588.29 BogoMips).
My book : http://www.AbominableFirebug.com/
_


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Thank you.
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