[ltt-dev] Problems with LTTV GUI

Gianluca Valentino g_v_valentino at hotmail.com
Tue May 18 10:52:01 EDT 2010


Dear Jerome,

I think I have destroyed it correctly, at least that's what it says when I run it in text-mode (see no. 8 below).. I will explain each step that I have done after booting with the LTTng patched kernel below:

1. Edit system-wide configuration (as explained in the guide: http://lttng.org/cgi-bin/gitweb.cgi?p=lttv.git;a=blob_plain;f=LTTngManual.html#section2)
mkdir /mnt/debugfs
cp /etc/fstab /etc/fstab.lttng.bkp
echo "debugfs         /mnt/debugfs    debugfs rw              0       0"  >> /etc/fstab
2. Insert the specific modules (every time I boot)
modprobe kernel-trace
modprobe mm-trace
modprobe net-trace
modprobe fs-trace
modprobe jbd2-trace
modprobe ext4-trace
modprobe syscall-trace
modprobe trap-trace
modprobe ltt-statedump

I couldn't do

modprobe ltt-trace-control
modprobe ltt-marker-control
modprobe ltt-tracer
modprobe ltt-serialize
modprobe ltt-relay

However these should be in-built as they appear as .o and .c files in /lib/modules/2.6.31.5-custom/build/ltt

3. I installed the ltt-control and lttv packages as explained in the guide above

4. echo text > sudo tee -a /mnt/debugfs/ltt/write_event does not give me any error

5. I execute sudo ltt-armall, and sudo lttv-gui

6. I click on the 'traffic light' icon and I enter the root password. I click on start and then stop. LTTng Trace Control asks me if I want to open the trace in LTTV. I click yes, and it tells me "Cannot open trace: maybe you should enter in the directory to select it". Checking the sizes of the files in /tmp/trace1 (as you asked me) are all zero-sized.

7. With the CLI version of lttv: I execute sudo lttctl -C -w /tmp/trace1 trace1. It gives me:

Linux Trace Toolkit Trace Control 0.84-07042010

Controlling trace : trace1

lttctl: Creating trace
lttctl: Forking lttd
Linux Trace Toolkit Trace Daemon 0.84-07042010

Reading from debugfs directory : /sys/kernel/debug/ltt/trace1
Writing to trace directory : /tmp/trace1

lttctl: Starting trace
ubuntu at beagleboard:~$

8. Then I execute sudo lttctl -D trace1 to destroy trace. It gives me:



Linux Trace Toolkit Trace Control 0.84-07042010

Controlling trace : trace1

lttctl: Pausing trace
lttctl: Destroying trace
ubuntu at beagleboard:~$

9. The only error I encountered was when I tried lttv -m textDump -t /tmp/trace1 for a simple trace dump in text format.

After a series of long lines like:

The input data file /tmp/trace1/net_0 does not contain a trace

it told me WARNING **: Trace /tmp/trace1 has no metadata tracefile

and CRITICAL **: cannot open trace /tmp/trace1

and finally: /usr/local/bin/lttv: line 15: 2152 Segmentation fault $0.real $*



Date: Tue, 18 May 2010 21:27:20 +0800
Subject: Re: [ltt-dev] Problems with LTTV GUI
From: jeromezhr at gmail.com
To: g_v_valentino at hotmail.com
CC: ltt-dev at lists.casi.polymtl.ca

2010/5/18 Gianluca Valentino <g_v_valentino at hotmail.com>







 


From: g_v_valentino at hotmail.com
To: jeromezhr at gmail.com
Subject: RE: [ltt-dev] Problems with LTTV GUI

Date: Tue, 18 May 2010 15:18:16 +0200



Dear Jerome,
 
Thanks for your reply. Yes they are all zero-sized..
 
Regards,
 
Gianluca
 


So I think there must be some problems in traceing.
Have you destroyed your trace correctly?
-- 
Regards,

Jerome
 		 	   		  
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