[ltt-dev] simple userspace tracing with LTTng 0.9.10

[Akyurek, Ali (EXT)]

Hi,

Since there is no specialized trace concept in legacy LTTng 0.9.10, 

I'm thinking of defining a new marker and use it as below. I think this would be ok, but it'll require many additions.

What if i use an existing trace_mark like kernel_printk below, instead of defining a new marker. 
I know this is ugly and tricky, but can i make it work?

Thanks.



static ssize_t write_event(struct file *file, const char __user *user_buf,
		size_t count, loff_t *ppos)
{
.
..
...
-	marker = &GET_MARKER(userspace, event);
-	ltt_specialized_trace(marker, marker->single.probe_private,
-		page, count + 1, sizeof(char));

+	trace_mark(userspace_event,"%s",string_from_user_buf);

...
..
.
}

 

-----Ursprüngliche Nachricht-----
Von: Mathieu Desnoyers [mailto:compudj at krystal.dyndns.org] 
Gesendet: Mittwoch, 28. Januar 2009 16:57
An: Akyurek, Ali (EXT)
Cc: ltt-dev at lists.casi.polymtl.ca
Betreff: Re: [ltt-dev] simple userspace tracing with LTTng 0.9.10

* Akyurek, Ali (EXT) (ali.akyurek.ext at siemens.com) wrote:
> Hi all,
>  
> I've used simple userspace event tracing with the latest version by
> writing to the  mnt/debugfs/ltt/write_event.
> But now i'm using an old LTTng (because i have to), 0.9.10. 
> 
> Is it possible to port this simple uspace tracing feature to the old
> lttng versions?
> 
> Or it is not possible because of some architectural restrictions of
> kernel or LTTng?
> Thanks.
> 

That should be easily doable, as long as you have a kernel with debugfs.

The main patch concerned is :
lttng-userspace-write-event.patch

Mathieu

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-- 
Mathieu Desnoyers
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