[lttng-dev] LTTng trace files organize

[Jeffrey Chen]

We need to read the traces while trace session is still running. We set the max-file-size. When LTTng rollover to the next trace file, we would want to read the old traces from the old trace files. If LTTng separate the traces per CPU core, time T traces might be at the first trace file of CPU 1, but at 6th trace file of CPU 3. It is much harder for use to search for traces, when each CPU core writes their own trace files. We will need to do extra processing to search for the traces at time T for each CPU core's trace files.



> To: lttng-dev at lists.lttng.org
> From: Jonathan.rajotte-julien at efficios.com
> Date: Tue, 15 Dec 2015 14:47:47 -0500
> Subject: Re: [lttng-dev] LTTng trace files organize
> 
> Hey Jeffrey
> 
> On 2015-12-15 02:15 PM, Jeffrey Chen wrote:
> > Hi:
> >
> > I have a question on how LTTng organize trace files. I noticed by 
> > default for userspace tracing, LTTng writes a trace file per CPU core. 
> > So, I would get something like channel0_0, channel0_1, channel0_2, 
> > channel0_3, for the case of 4 CPU cores. Is there a way to config 
> > LTTng only writes to 1 trace file? This is much easier for us to 
> > organize the traces for our use case.
> If you don't mind me asking what exactly would be your use case here? 
> Folder separation is not enough (via  -o on lttng create) ?
> 
> Cheers
> 
> > Thanks.
> >
> >
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> > lttng-dev at lists.lttng.org
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> 
> -- 
> Jonathan R. Julien
> Efficios
> 
> 
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