[ltt-dev] Module example and Lttv-gui

Mathieu Desnoyers compudj at krystal.dyndns.org
Sat Jun 19 12:31:07 EDT 2010


* Fabien Royer (Fabien.Royer at arm.com) wrote:
> HI Mathieu,
> 
>

Hi Fabien,

> 
> I have installed successfully the LTTng on the beagle board and compile
> the sample kernel modules.
> 

Great!

[ CCing ltt-dev, as these explanation might be useful to others ]

>  
> 
> However I am not quite sure to understand. If  I am using lttv-gui to
> trace the marker example, it makes no difference to me than when I don't
> run it ! I mean to say I don't understand where the important data is
> while looking at the lttv gui as it just look the same to me when I run
> the example and when I don't. 

You mean the marker example data is flooded in other events ?

You should probably use the lttv event filer (the "and" logical door
icon) to filter by event. Use

  event.name=samples.subsystem_event

as filter string. It will only show these events. You can specifically
use the "filter" icon from the detailed event list if you want to
specify it for that list. You can even load multiple detailed event
lists with different filters if you like.

> 
>  
> 
> I am using Linux Trace Toolkit Visualizer 0.12.30-02102010 and Linux
> beagleboard 2.6.33.1-ga0ff4c3
> 
> Below is the output of dmesg. I would have liked to include the trace
> output but in the GUI there is no file-> save as.

Note that the trace is usually saved in a directory under /tmp.

Hope this helps,

Mathieu

> 
>  
> 
> Thanks in advance,
> 
> Regards,
> 
> Fabien
> 
>  
> 
> $ dmesg
> 
> .....
> 
> .....
> 
> LTT state dump begin
> 
> LTT state dump thread start
> 
> LTT state dump end
> 
> example init
> 
> Value 123, string example string
> 
> example exit
> 
> Number of event b : 10
> 
> LTT: 367 events written in channel syscall_state (cpu 0, index 0)
> 
> LTT: 32 events written in channel softirq_state (cpu 0, index 0)
> 
> LTT: 131 events written in channel task_state (cpu 0, index 0)
> 
> LTT: 359 events written in channel fd_state (cpu 0, index 0)
> 
> LTT: 3092 events written in channel vm_state (cpu 0, index 0)
> 
> LTT: 17 events written in channel irq_state (cpu 0, index 0)
> 
> LTT: 3 events written in channel netif_state (cpu 0, index 0)
> 
> LTT: 1 events written in channel global_state (cpu 0, index 0)
> 
> LTT: 34235 events written in channel kernel (cpu 0, index 0)
> 
> LTT: 1758 events written in channel mm (cpu 0, index 0)
> 
> LTT: 5992 events written in channel fs (cpu 0, index 0)
> 
> LTT: 1110 events written in channel rcu (cpu 0, index 0)
> 
> LTT: 4421 events written in channel net (cpu 0, index 0)
> 
> LTT: 352 events written in channel block (cpu 0, index 0)
> 
> LTT: 298 events written in channel metadata (cpu 0, index 0)
> 
> -- 
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-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com




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