stream based live time synchronized tracing?

stream based live time synchronized tracing?

[Alexander Aring]

Hi,

I am curious if there is any way of getting time synchronized traces
in a kind of stream based communication like pipes, sockets, etc. and
get high level event representation as ?libtraceevent? provides. I
would like to get all "merged" events from all machines provided by -A
parameters. I think it isn't required to get them in order, but the
timestamp should be synchronized.

I could probably build something like that with libtracecmd to have it
directly implemented in an application, but I am curious if there
exists any interest in having such a feature upstream? E.g. having
additional parameters like '--tsync-interval'.

A use-case would be live capturing of time synchronized events or what
I have in my mind to collect stats and doing kernel runtime
optimizations.

- Alex

Re: stream based live time synchronized tracing?

[Mathieu Desnoyers]

----- On Aug 15, 2022, at 9:28 AM, Alexander Aring aahringo@redhat.com wrote:

> Hi,
> 
> I am curious if there is any way of getting time synchronized traces
> in a kind of stream based communication like pipes, sockets, etc. and
> get high level event representation as ?libtraceevent? provides. I
> would like to get all "merged" events from all machines provided by -A
> parameters. I think it isn't required to get them in order, but the
> timestamp should be synchronized.
> 
> I could probably build something like that with libtracecmd to have it
> directly implemented in an application, but I am curious if there
> exists any interest in having such a feature upstream? E.g. having
> additional parameters like '--tsync-interval'.
> 
> A use-case would be live capturing of time synchronized events or what
> I have in my mind to collect stats and doing kernel runtime
> optimizations.

You may want to have a look at babeltrace2 [1]. It allows merging multiple
traces together as they are read. Using the "lttng-live" source, you can read
traces as they are produced.

Thanks,

Mathieu

[1] https://babeltrace.org


-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com

Re: stream based live time synchronized tracing?

[Steven Rostedt]

On Mon, 15 Aug 2022 09:28:48 -0400
Alexander Aring <aahringo@redhat.com> wrote:

> Hi,
> 
> I am curious if there is any way of getting time synchronized traces
> in a kind of stream based communication like pipes, sockets, etc. and
> get high level event representation as ?libtraceevent? provides. I
> would like to get all "merged" events from all machines provided by -A
> parameters. I think it isn't required to get them in order, but the
> timestamp should be synchronized.

Are these for guests, or machines on a network?

> 
> I could probably build something like that with libtracecmd to have it
> directly implemented in an application, but I am curious if there
> exists any interest in having such a feature upstream? E.g. having
> additional parameters like '--tsync-interval'.
> 
> A use-case would be live capturing of time synchronized events or what
> I have in my mind to collect stats and doing kernel runtime
> optimizations.

So basically not save to a file? Just record the events live and interleave
them for different machines?

I'm not exactly sure what you are asking for. Can you please elaborate some
more?

Thanks,

-- Steve