RE: Libraw1394 question

[Mark K. <mk...@co...>]

Sebastien,
   Without waiting for the ACK, or without waiting for the response packet?
Mark

-----Original Message-----
From: Sebastien Rougeaux [mailto:Seb...@sy...]
Sent: Wednesday, May 10, 2000 7:19 PM
To: dai...@el...
Cc: ana...@ut...; lin...@li...
Subject: Re: Libraw1394 question


>>>>> "Olivier" == Olivier Daigle <dai...@el...> writes:

Olivier> --------------80790F6F4A9A7A46D27C5FE8 Content-Type: text/plain;
Olivier> charset=us-ascii Content-Transfer-Encoding: 7bit

Olivier> Hi Ashok, I managed to exchange raw data between 2 computers by
using
Olivier> an FCP-like method and libraw1394. Mainly, I copied FCP code and
Olivier> extended it to allow data being transferred by chunks of 2k
(instead
Olivier> of 512 bytes with bare FCP code).  This was pretty easy. Problem
is:
Olivier> there is a long delay between every data transfer and even with
fast
Olivier> machines (Pentium III 450MHz) and I can't manage to get data
Olivier> transferred faster than 2.5 Mbytes/sec. By using Frank Bonin's
Olivier> implementation of IP-over-1394 (which use async transactions), I
can
Olivier> ftp-transfer as fast as 15Mbytes/sec with slow machines (pentium
Olivier> 200MMX) so I guess I should be able to do as fast as him...

Olivier> I'm working on a way to speed-up transfer because I need at least
Olivier> 12Mbytes/sec.  I think the problem is that the code waits for an
Olivier> acknowledge before sending another packet. If you have any other
Olivier> suggestions, please help.

The OHCI driver has been designed to send multiple packets without waiting 
for the ack (currently the max is set to 32)... However I think it never
happens because of the internal mechanism of the subsystem/libraw. You
probably should ask Andreas Bombe about that.

-- 
Sebastien Rougeaux
RSISE, The Australian National University

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