Re: bluetooth 2.0 is extremely slow

[Mike Cronenworth <mike@xxxxxxxxxx>]

-------- Original Message  --------
Subject: Re:bluetooth 2.0 is extremely slow
From: Mike Cronenworth <mike@xxxxxxxxxx>
To: Bastien Nocera <bnocera@xxxxxxxxxx>
Date: 04/05/2008 12:50 AM

I punched myself into loading Windows XP (latest updates, latest drivers) and the same file (or any 1 meg file) transfers in *10 seconds*. A factor of four on speed improvement. There's nothing wrong with the firmware.

I saw someone fixed this by forcing larger MTUs.
http://lists.freebsd.org/pipermail/...ary/000847.html
<http://lists.freebsd.org/pipermail/freebsd-bluetooth/2007-January/000847.html>

Before modifying the OpenOBEX sources, I posted a message on their
board, but I haven't heard anything yet. Does anyone have any experience
with this?
    

OpenObex upstream is pretty much dead(-ish). Let's call it maintenance
mode.

  

I have tried the fedora-list without an answer. Also, the OpenOBEX 
developers are silent on this. Is this because no one has a 2.0 adapter 
and 2.0 device?
    

Probably not, one of the upstream for OpenObex is Marcel Holtmann, and
he certainly has more Bluetooth 2.0 devices than you or I.

Test the patch, tell us if it works, and mail the bluez-users list about
it. There's also ACL and SCO MTUs to take in consideration, and I would
guess the bug is more likely to be there (in the kernel, in the firmware
of your dongle, or the firmware of your phone) than solely in OpenObex.
  

I will try messing with OpenOBEX and report back. If no one else ventures into this... it might be a while. I don't have a lot of time to give to this.

Cheers

  

OK,

I applied the attached patch. I'm putting this up for review, and any suggestions (should this be posted somewhere else, etc.). My transfer time went from 40 seconds to 10 seconds. It now matches Windows XP performance. Just add it to the RPM spec like the existing patches.

Regards,
Michael

--- openobex-1.3/include/obex_const.h.mtu	2006-03-08 06:18:55.000000000 -0600
+++ openobex-1.3/include/obex_const.h	2008-04-09 21:26:53.000000000 -0500
@@ -192,8 +192,8 @@
 #define OBEX_RSP_DATABASE_LOCKED	0x61
 
 /* Min, Max and default transport MTU */
-#define OBEX_DEFAULT_MTU	1024
-#define OBEX_MINIMUM_MTU	255
+#define OBEX_DEFAULT_MTU	16384
+#define OBEX_MINIMUM_MTU	2048
 #define OBEX_MAXIMUM_MTU	65535
 
 /* Optimum MTU for various transport (optimum for throughput).

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