[lttng-dev] adding new channel

[Julien Desfossez]

Hi,

I'm just curious, is there a problem with creating new sessions when
needed for this kind of use-case ?

Thanks,

Julien

On 15-02-20 02:25 PM, Anand Neeli wrote:
> Thanks for the reply.
> 
> I think adding channels on the fly must be supported.
> From debugging point of view, it will be good if we can add channels on
> the fly with each channel having different set of events.
> Even "stop tracing" and adding channel doesnt help now.
> 
> Thanks,
> Anand Neeli
> 
> On Sat, Feb 21, 2015 at 12:35 AM, Philippe Proulx
> <eeppeliteloop at gmail.com <mailto:eeppeliteloop at gmail.com>> wrote:
> 
>     On Fri, Feb 20, 2015 at 2:00 PM, Anand Neeli <anand.neeli at gmail.com
>     <mailto:anand.neeli at gmail.com>> wrote:
>     > Hi All,
>     > Is adding a new channel to an existing(running) session supported?
> 
>     No.
>     >
>     > i get following error when doing this.
>     > Error: Channel myc5: Tracing already started
>     >
>     > Is there any way to add channels on the fly?
> 
>     No. LTTng's documentation [1] states:
> 
>         Note: Because of a current limitation, all channels must be
>         created prior to beginning tracing in a given tracing session,
>         i.e. before the first time you do lttng start.
> 
>         Since a channel is automatically created by enable-event
>         only for the specified domain, you cannot, for example, enable
>         a kernel domain event, start tracing and then enable a user
>         space domain event because no user space channel exists
>         yet and it's too late to create one.
> 
>         For this reason, make sure to configure your channels
>         properly before starting the tracers for the first time!
> 
>     Phil
> 
>     [1] http://lttng.org/docs/#doc-enabling-disabling-channels
> 
>     > I'm using 2.4.1 version
>     >
>     > Thanks,
>     > Anand Neeli
>     >
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> 
> 
> 
> 
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