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<body lang="EN-US" link="#0563C1" vlink="#954F72" style="word-wrap:break-word"><div>Le vendredi 22 octobre 2021 à 03:48 +0000, Mohammad Sheraj via gstreamer-devel a écrit :</div><blockquote type="cite" style="margin:0 0 0 .8ex; border-left:2px #729fcf solid;padding-left:1ex"><div class="WordSection1"><p class="MsoNormal">Hi,<o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">I want to improve my understanding of Gstreamer.<o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">How many threads are there in this GStreamer pipeline?<o:p></o:p></p><p class="MsoNormal">gst-launch-1.0 autovideosrc ! queue ! fakesink<o:p></o:p></p></div></blockquote><div><br></div><div>It's impossible to say which video source will be picked by autovideosrc. Replace this magic thing with an explicit src, like videotestsrc, then you should have 4 thread,</div><div><br></div><div> - source streaming thread</div><div>- queue streaming thread</div><div>- main thread (gst-launch runs a GLib main-loop, though this is optional)</div><div>- Some thread pool.</div><div><br></div><div>You may have more threads if you use an element that initialize GIO, those will stay mostly idle.</div><div><br></div><blockquote type="cite" style="margin:0 0 0 .8ex; border-left:2px #729fcf solid;padding-left:1ex"><div class="WordSection1"><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">I want the total number and function of each thread.<o:p></o:p></p><p class="MsoNormal">I searched online and in the documentation (<a href="https://gstreamer.freedesktop.org/documentation/application-development/advanced/threads.html?gi-language=c#">https://gstreamer.freedesktop.org/documentation/application-development/advanced/threads.html?gi-language=c#</a>) but couldn't find a clear answer.<o:p></o:p></p></div></blockquote><div><br></div><div>You can track GStreamer related thread in your software with the STREAM_STATUS message. All other threads are from third party libraries, glib or you libc.</div><div><br></div><blockquote type="cite" style="margin:0 0 0 .8ex; border-left:2px #729fcf solid;padding-left:1ex"><div class="WordSection1"><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">My knowledge is that there is a main loop thread, an event thread (not sure) and two (because of queue element) buffer threads here.<o:p></o:p></p><p class="MsoNormal">This gives a total of 4 threads for the mentioned pipeline.</p></div></blockquote><blockquote type="cite" style="margin:0 0 0 .8ex; border-left:2px #729fcf solid;padding-left:1ex"><div class="WordSection1"><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">Am I correct? Or is there some other mechanism?<o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">**Experiments:**<o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">Running the first time gives 8 threads initially.<o:p></o:p></p><p class="MsoNormal">/ # ps -T | grep "gst"<o:p></o:p></p><p class="MsoNormal">3681 root 0:00 gst-launch-1.0 autovideosrc ! queue ! fakesink<o:p></o:p></p><p class="MsoNormal">3702 root 0:00 gst-launch-1.0 autovideosrc ! queue ! fakesink<o:p></o:p></p><p class="MsoNormal">3703 root 0:00 gst-launch-1.0 autovideosrc ! queue ! fakesink<o:p></o:p></p><p class="MsoNormal">3704 root 0:00 gst-launch-1.0 autovideosrc ! queue ! fakesink<o:p></o:p></p><p class="MsoNormal">3716 root 0:00 {queue0:src} gst-launch-1.0 autovideosrc ! queue ! fakesink<o:p></o:p></p><p class="MsoNormal">3717 root 0:00 {fake-auto-video} gst-launch-1.0 autovideosrc ! queue ! fakesink<o:p></o:p></p><p class="MsoNormal">3718 root 0:00 {gmain} gst-launch-1.0 autovideosrc ! queue ! fakesink<o:p></o:p></p><p class="MsoNormal">3719 root 0:00 {pool} gst-launch-1.0 autovideosrc ! queue ! fakesink<o:p></o:p></p><p class="MsoNormal">3729 root 0:00 grep gst<o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">After some time it becomes 7 threads<o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">/ # ps -T | grep "gst"<o:p></o:p></p><p class="MsoNormal">3681 root 0:00 gst-launch-1.0 autovideosrc ! queue ! fakesink<o:p></o:p></p><p class="MsoNormal">3702 root 0:00 gst-launch-1.0 autovideosrc ! queue ! fakesink<o:p></o:p></p><p class="MsoNormal">3703 root 0:00 gst-launch-1.0 autovideosrc ! queue ! fakesink<o:p></o:p></p><p class="MsoNormal">3704 root 0:00 gst-launch-1.0 autovideosrc ! queue ! fakesink<o:p></o:p></p><p class="MsoNormal">3716 root 0:00 {queue0:src} gst-launch-1.0 autovideosrc ! queue ! fakesink<o:p></o:p></p><p class="MsoNormal">3717 root 0:02 {fake-auto-video} gst-launch-1.0 autovideosrc ! queue ! fakesink<o:p></o:p></p><p class="MsoNormal">3718 root 0:00 {gmain} gst-launch-1.0 autovideosrc ! queue ! fakesink<o:p></o:p></p><p class="MsoNormal">3731 root 0:00 grep gst<o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">I did `strace -p 3681` and so on and found <o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">3681:<o:p></o:p></p><p class="MsoNormal">ppoll([{fd=3, events=POLLIN}, {fd=9, events=POLLIN}], 2, NULL, NULL, 0<o:p></o:p></p><p class="MsoNormal">3702:<o:p></o:p></p><p class="MsoNormal">ioctl(11, BINDER_WRITE_READ<o:p></o:p></p><p class="MsoNormal">3703<o:p></o:p></p><p class="MsoNormal">ioctl(11, BINDER_WRITE_READ<o:p></o:p></p><p class="MsoNormal">3704:<o:p></o:p></p><p class="MsoNormal">ioctl(11, BINDER_WRITE_READ<o:p></o:p></p><p class="MsoNormal">3716:</p></div></blockquote><blockquote type="cite" style="margin:0 0 0 .8ex; border-left:2px #729fcf solid;padding-left:1ex"><div class="WordSection1"><p class="MsoNormal">...<o:p></o:p></p><p class="MsoNormal">futex(0x5580a842a8, FUTEX_WAIT_PRIVATE, 11083, NULL) = 0<o:p></o:p></p><p class="MsoNormal">3717:<o:p></o:p></p><p class="MsoNormal">...<o:p></o:p></p><p class="MsoNormal">ppoll([{fd=6, events=POLLIN|POLLPRI|POLLERR|POLLHUP|POLLNVAL}], 1, {tv_sec=0, tv_nsec=31373754}, NULL, 8) = 0 (Timeout)<o:p></o:p></p><p class="MsoNormal">futex(0x5580a842a8, FUTEX_WAKE_PRIVATE, 1) = 1<o:p></o:p></p><p class="MsoNormal">futex(0x5580a84290, FUTEX_WAKE_PRIVATE, 1) = 1<o:p></o:p></p><p class="MsoNormal">3718:<o:p></o:p></p><p class="MsoNormal">ppoll([{fd=5, events=POLLIN}], 1, NULL, NULL, 0<o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">What does this mean?<o:p></o:p></p></div></blockquote><div><br></div><div>There is no mainline code in GStreamer that would use Android ioctl BINDER, so I suppose you are using some HW specific video source and then sky is the limit on what that third party camera stack may do.</div><div><br></div><blockquote type="cite" style="margin:0 0 0 .8ex; border-left:2px #729fcf solid;padding-left:1ex"><div class="WordSection1"><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">Thanks and Regards,<o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">Mohammad Sheraj<o:p></o:p></p><p class="MsoNormal">Connected Smart Systems (CSS)<o:p></o:p></p><p class="MsoNormal">Qualcomm<o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p></div></blockquote><div><br></div><div><span></span></div></body></html>