From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <1077309735.4036712706cd0@alcor.concordia.ca> Date: Fri, 20 Feb 2004 15:42:15 -0500 From: =?iso-8859-1?b?TWFyYy1BbmRy6SA=?= =?iso-8859-1?b?TGF2ZXJkaehyZQ==?= To: Marcel Holtmann Cc: BlueZ Mailing List Subject: Re: [Bluez-users] Major slowdown when service discovery+opening a service happens on two systems trying to talk to each other References: <1077022337.2841.15.camel@pegasus> <1077033023.4032383f0b3d3@alcor.concordia.ca> <1077034212.2665.19.camel@pegasus> In-Reply-To: <1077034212.2665.19.camel@pegasus> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 List-ID: I read the parts allowing me to have some kind of understanding of what's going on :) Sorry for the delay, I had a hard deadline for a report. Here's the situation in more Bluetooth-compliant terms: Configuration: Belkin FT0003 USB dongles RedHat 9 with kernel 2.4.28, from RedHat Running with latest released versions of BlueZ Running Impronto 1.18 Running Java SDK 1.4.2.3 Bluetooth activity (all happening in Java): Implicit: Inquiry Scan [device is set as GIAC] Thread 1: Inquiry [aka Device Discovery] [runs perpetually, with some sleeping between each iteration] Thread 2: Page Scan [opening a service and waiting for clients with acceptAndOpen()] Thread 3: SDP Paging + Connection [Service Discovery] [does so when new devices are found, could happen anytime. Sleeps most of the time] Thread 4: Paging + Connection [L2CAP Connection as a slave] [happens at user's input] Computer A and Computer B are running this configuration Planned Test: Start program on both computers Wait for both Computer A and Computer B to discover each other via Inquiry User prompts Computer A to send a message to Computer B [creating a L2CAP connection] Computer B reads the message and closes the connection Both shut down their services and exit cleanly What happens: Inconsistent behaviour. Service discovery can happen promptly on Computer A and never finish on Computer B. Sometimes, service discovery completes around 20 seconds for both systems. The L2CAP connection may not establish itself. Behaviour varies at every test's run, but generally the results look like a deadlock has occured somewhere. Very low Bluetooth performance compared to the speed of other configurations. I hope this makes more sense. I have to read more about the Bluetooth spec, see what I'm doing wrong Bluetooth-wise. Any sections particularly? I'm also considering adjusting the settings of hciconfig as well as upgrading to kernel 2.6 (I was told that it generally had a huge improvement I/O-wise) -- Marc-André Laverdière (†) Étudiant coop. en génie logiciel - Software Engineering Co-Op Student Université Concordia - Concordia University /"\ \ / ASCII Ribbon Campaign X against HTML e-mail / \ Selon Marcel Holtmann : > Hi Marc-Andre, > > > Only the 1.2 spec is available for people not from member companies. I > hope > > this > > version is OK. > > this version is almost fine. > > > I'll get the non-Java terminology right and I'll write an understandable > report > > then. This is frustrating. > > I don't think so. > > inquiry scan -> device is visible > page scan -> device is connectable > > inquiry -> search for other devices > page -> connect to another device > > SDP connection -> service discovery (includes page) > > Regards > > Marcel > >