help with using GST_TRACER

[mariannasb]

Hi,

I have been trying to use the GST_TRACER and my first problem is the difficulty of finding documentation and understanding how to use it.

Is there other documentation available other than https://cgit.freedesktop.org/gstreamer/gstreamer/tree/docs/design/part-tracing.txt ?

From what I understand from there I can use the tracer by setting the GST_TRACERS env variable to one or more of the following: latency, rusage, stats, leaks.
Then setting as well GST_DEBUG=GST_TRACER:7 so that the output of the tracer shows up in the debug log.
Then there is the possibility of passing the debug log to gst-stats-1.0 so it gets parsed.

From what I understand "latency" will tell me the time it takes for a buffer to traverse the whole pipeline: go from source to sink.
I'm actually interested in the individual processing time of each element as well, is it possible to get this information?
And it would also be helpful if gst-stats could print the latency information like it does for buffer size: min/avg/max

[Stefan Sauer]

Hi marianna,
On 10/18/2016 08:40 AM, mariannasb wrote:
> Hi,
>
> I have been trying to use the GST_TRACER and my first problem is the
> difficulty of finding documentation and understanding how to use it.
>
> Is there other documentation available other than
> https://cgit.freedesktop.org/gstreamer/gstreamer/tree/docs/design/part-tracing.txt
> ?
That is all the docs. Each tracer has a doc blob in the sources too, but
we don't have them in the generated docs yet.

>
> From what I understand from there I can use the tracer by setting the
> GST_TRACERS env variable to one or more of the following: latency, rusage,
> stats, leaks.
> Then setting as well GST_DEBUG=GST_TRACER:7 so that the output of the tracer
> shows up in the debug log.
> Then there is the possibility of passing the debug log to gst-stats-1.0 so
> it gets parsed.
>
> From what I understand "latency" will tell me the time it takes for a buffer
> to traverse the whole pipeline: go from source to sink.
> I'm actually interested in the individual processing time of each element as
> well, is it possible to get this information?

gst-stats is showing those if you use stats+rsuage. Please note that the
cpu usage we show is not always correct. This is where we should merge
the existing tools.

Stefan

> And it would also be helpful if gst-stats could print the latency
> information like it does for buffer size: min/avg/max
>
>
>
> --
> View this message in context: http://gstreamer-devel.966125.n4.nabble.com/help-with-using-GST-TRACER-tp4680090.html
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[mariannasb]

Hi Stefan,

Thanks for pointing me to the existing documentation during the conference :)

>> From what I understand "latency" will tell me the time it takes for a buffer
>> to traverse the whole pipeline: go from source to sink.
>> I'm actually interested in the individual processing time of each element as
>> well, is it possible to get this information?
>gst-stats is showing those if you use stats+rsuage. Please note that the
>cpu usage we show is not always correct. This is where we should merge
>the existing tools.

Yes I run gst-stats after running a pipe with GST_TRACERS="stats;rusage" and that shows cpu usage and some buffer information.
I'm not very interested in the cpu load, so for me it is not a problem if it isn't always right.

What I really want is the latency information (the individual processing time of each element).
And it think it could be nice if that could be parsed by gst-stats to show latency information like fx. the buffer size information is shown.

The only thing I can get right now is the time from src element to sink element when setting GST_TRACERS=latency.

I'm running 1.8.0 so I might not be up to date with new features.

Is it possible to get the information I want at the moment or is there any interest/plan to add such functionality?

Thanks

Marianna

[Stefan Sauer]

On 10/21/2016 12:36 PM, mariannasb wrote:

> Hi Stefan,
>
> Thanks for pointing me to the existing documentation during the conference
> :)
>
>>> From what I understand "latency" will tell me the time it takes for a
>>> buffer
>>> to traverse the whole pipeline: go from source to sink.
>>> I'm actually interested in the individual processing time of each element
>>> as
>>> well, is it possible to get this information?
>> gst-stats is showing those if you use stats+rsuage. Please note that the
>> cpu usage we show is not always correct. This is where we should merge
>> the existing tools.
> Yes I run gst-stats after running a pipe with GST_TRACERS="stats;rusage" and
> that shows cpu usage and some buffer information.
> I'm not very interested in the cpu load, so for me it is not a problem if it
> isn't always right.
>
> What I really want is the latency information (the individual processing
> time of each element).
> And it think it could be nice if that could be parsed by gst-stats to show
> latency information like fx. the buffer size information is shown.

RIghtm we can add average processing time. At least for filter elements
(effects, converter, codecs). It is really tricky to get this right for
elements with multiple src/sink pads. I'll take a look.

Stefan

>
> The only thing I can get right now is the time from src element to sink
> element when setting GST_TRACERS=latency.
>
> I'm running 1.8.0 so I might not be up to date with new features.
>
> Is it possible to get the information I want at the moment or is there any
> interest/plan to add such functionality?
>
> Thanks
>
> Marianna
>
>
>
> --
> View this message in context: http://gstreamer-devel.966125.n4.nabble.com/help-with-using-GST-TRACER-tp4680090p4680157.html
> Sent from the GStreamer-devel mailing list archive at Nabble.com.
> _______________________________________________
> gstreamer-devel mailing list
> [hidden email]
> https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel

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