mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2025-01-28 01:58:19 +00:00
dc159be1b2
Original commit message from CVS: * docs/random/ensonic/distributed.txt: add some ideas about doing distributed processing * docs/random/ensonic/profiling.txt: get_rusage look promising
78 lines
2.7 KiB
Text
78 lines
2.7 KiB
Text
$Id$
|
|
|
|
= profiling =
|
|
|
|
== what information is interesting? ==
|
|
* pipeline throughoutput
|
|
if we know the cpu-load for a given datastream, we could extrapolate what the
|
|
system can handle
|
|
-> qos profiling
|
|
* load distribution
|
|
which element causes which cpu load/memory usage
|
|
|
|
|
|
= qos profiling =
|
|
|
|
* what data is needed ?
|
|
* streamtime,propotion pairs from sinks
|
|
draw a graph with gnuplot or similar
|
|
* number of frames in total
|
|
* number of frames dropped from each element that support QOS
|
|
elements that don't support QOS wont have this information anyway
|
|
|
|
* idea1: parse data from debug log
|
|
GST_QOS gstbasesink.c:1188:gst_base_sink_send_qos:<xvimagesink0> qos: proportion: 0.895615, diff -16437500, timestamp 0:00:09.208333333
|
|
basesink gstbasesink.c:1542:gst_base_sink_render_object:<xvimagesink0> buffer late, dropping
|
|
basesink gstbasesink.c:2534:gst_base_sink_change_state:<alsasink0> rendered: 1028, dropped: 0
|
|
basesink gstbasesink.c:2534:gst_base_sink_change_state:<xvimagesink0> rendered: 598, dropped: 10
|
|
|
|
+ easy to do
|
|
- debug log changes timing
|
|
|
|
* idea2: query data (via gst-launch)
|
|
* add -r, --report option to gst-launch
|
|
* send duration to get total number of frames (GST_FORMAT_DEFAULT for video is frames)
|
|
* during playing we need to capture QOS-events to record 'streamtime,proportion' pairs
|
|
gst_pad_add_event_probe(video_sink->sink_pad,handler,data)
|
|
* during playback we like to know when an elemnt drops frames
|
|
what about elements sending a qos_action message?
|
|
* after EOS, send qos-queries to each element in the pipeline
|
|
* qos-query will return:
|
|
number of frames rendered
|
|
number of frames dropped
|
|
* print a nice table with the results
|
|
* QOS stats first
|
|
* list of 'streamtime,proportion' pairs
|
|
|
|
+ robust
|
|
+ also available to application
|
|
- changes in core
|
|
|
|
= core profiling =
|
|
|
|
* scheduler keeps a list of usecs the process function of each element was
|
|
running
|
|
* process functions are: loop, chain, get, they are driven by gst_pad_push() and
|
|
gst_pad_pull_range()
|
|
* scheduler keeps a sum of all times
|
|
* each gst-element has a profile_percentage field
|
|
|
|
* when going to play
|
|
* scheduler sets sum and all usecs in the list to 0
|
|
* when handling an element
|
|
* remember old usecs t_old
|
|
* take time t1
|
|
* call elements processing function
|
|
* take time t2
|
|
* t_new=t2-t1
|
|
* sum+=(t_new-t_old)
|
|
* profile_percentage=t_new/sum;
|
|
* should the percentage be averaged?
|
|
* profile_percentage=(profile_percentage+(t_new/sum))/2.0;
|
|
|
|
* the profile_percentage shows how much CPU time the element uses in relation
|
|
to the whole pipeline
|
|
|
|
* check get_rusage() based cpu usage detection in buzztard
|
|
this together with pad_probes could gives us decent application level profiles
|
|
|