[Spice-devel] [PATCH spice-gtk v2 3/3] channel-display: Instrument code to get frame and queue statistics

Victor Toso victortoso at redhat.com
Wed Jan 23 14:14:37 UTC 2019


On Wed, Jan 23, 2019 at 08:57:36AM -0500, Frediano Ziglio wrote:
> > On Wed, Jan 23, 2019 at 11:28:57AM +0000, Frediano Ziglio wrote:
> > > This patch is based on some work from Victor Toso (statistics) and
> > > Snir Sheriber (GStreamer probing).
> > > All GstBuffers are queued into decoding_queue and a probe
> > > is attached to the sink in order to understand when the
> > > buffers are decoded.
> > > When a buffer is decoded the time spent and queue length
> > > are computed.
> > > 
> > > Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
> > > ---
> > >  src/channel-display-gst.c  | 45 +++++++++++++++++++++++++++++++++-----
> > >  src/channel-display-priv.h |  3 +++
> > >  src/channel-display.c      |  1 +
> > >  3 files changed, 43 insertions(+), 6 deletions(-)
> > > 
> > > Changes since v1:
> > > - use G_GUINT64_FORMAT instead of PRIu64, SPICE_DEBUG is using GLib
> > >   function which expects GNU formatting, it gives a warning compiling
> > >   for Windows
> > > 
> > > diff --git a/src/channel-display-gst.c b/src/channel-display-gst.c
> > > index 08c9f8fb..c15f94f2 100644
> > > --- a/src/channel-display-gst.c
> > > +++ b/src/channel-display-gst.c
> > > @@ -248,6 +248,12 @@ static SpiceGstFrame
> > > *get_decoded_frame(SpiceGstDecoder *decoder, GstBuffer *buf
> > >      if (num_frames_dropped != 0) {
> > >          SPICE_DEBUG("the GStreamer pipeline dropped %u frames",
> > >          num_frames_dropped);
> > >      }
> > > +    if (gstframe) {
> > > +        const SpiceFrame *frame = gstframe->encoded_frame;
> > > +        uint64_t duration = g_get_monotonic_time() - frame->creation_time;
> > > +        SPICE_DEBUG("frame mm_time %u size %u decoded time %"
> > > G_GUINT64_FORMAT " queue %u",
> > > +                    frame->mm_time, frame->size, duration,
> > > decoder->decoding_queue->length);
> 
> [1]
> 
> > > +    }
> > >      return gstframe;
> > >  }
> > >  
> > > @@ -391,6 +397,34 @@ static void app_source_setup(GstElement *pipeline
> > > G_GNUC_UNUSED,
> > >      gst_caps_unref(caps);
> > >      decoder->appsrc = GST_APP_SRC(gst_object_ref(source));
> > >  }
> > > +
> > > +static GstPadProbeReturn
> > > +sink_event_probe(GstPad *pad, GstPadProbeInfo *info, gpointer data)
> > > +{
> > > +    SpiceGstDecoder *decoder = (SpiceGstDecoder*)data;
> > > +
> > > +    if (info->type & GST_PAD_PROBE_TYPE_BUFFER) { // Buffer arrived
> > 
> > C-style comments instead?
> > 
> 
> C99 added "//" style comment, so unless you want C89 compatibility
> the comment above IS C-style.
> We use the new style in a lot of places for short comments.
> 
> > > +        GstBuffer *buffer = GST_PAD_PROBE_INFO_BUFFER(info);
> > > +        g_mutex_lock(&decoder->queues_mutex);
> > > +        SpiceGstFrame *gstframe = get_decoded_frame(decoder, buffer);
> > > +        if (gstframe) {
> > > +            free_gst_frame(gstframe);
> > > +        }
> 
> [2]
> 
> > > +        g_mutex_unlock(&decoder->queues_mutex);
> > > +    }
> > > +    return GST_PAD_PROBE_OK;
> > > +}
> > > +
> > > +/* This function is called to used to set a probe on the sink */
> > > +static void
> > > +add_elem_cb(GstBin * pipeline, GstBin * bin, GstElement * element,
> > > SpiceGstDecoder *decoder)
> > > +{
> > > +    if (GST_IS_BASE_SINK(element) && decoder->appsink == NULL) {
> > > +        GstPad *pad = gst_element_get_static_pad(element, "sink");
> > > +        gst_pad_add_probe(pad, GST_PAD_PROBE_TYPE_BUFFER,
> > > sink_event_probe, decoder, NULL);
> > > +        gst_object_unref(pad);
> > > +    }
> > > +}
> > >  #endif
> > >  
> > >  static gboolean create_pipeline(SpiceGstDecoder *decoder)
> > > @@ -455,6 +489,7 @@ static gboolean create_pipeline(SpiceGstDecoder
> > > *decoder)
> > >  #endif
> > >      }
> > >  
> > > +    g_signal_connect(playbin, "deep-element-added",
> > > G_CALLBACK(add_elem_cb), decoder);
> > >      g_signal_connect(playbin, "source-setup",
> > >      G_CALLBACK(app_source_setup), decoder);
> > >  
> > >      g_object_set(playbin,
> > > @@ -660,12 +695,10 @@ static gboolean
> > > spice_gst_decoder_queue_frame(VideoDecoder *video_decoder,
> > >      GST_BUFFER_DTS(buffer) = GST_CLOCK_TIME_NONE;
> > >      GST_BUFFER_PTS(buffer) = gst_clock_get_time(decoder->clock) -
> > >      gst_element_get_base_time(decoder->pipeline) + ((uint64_t)MAX(0,
> > >      latency)) * 1000 * 1000;
> > >  
> > > -    if (decoder->appsink != NULL) {
> > 
> > From the commit log, I don't follow why this check can be removed
> > 
> 
> Oh, we use the decoding_queue to match the input with the output and compute
> the decoded time, see [1] and [2].

Yes, that I can follow from commit log. What I cannot follow was
what I asked, the check if (decoder->appsink != NULL) was added
almost a year ago with:

    commit 424397546463698c2912b15449ef5e94f2c39c12
    Author: Snir Sheriber <ssheribe at redhat.com>
    Date:   Thu Mar 8 15:57:31 2018 +0200
    Gstreamer: Use GstVideoOverlay if possible

note:

    -    SpiceGstFrame *gst_frame = create_gst_frame(buffer, frame);
    -    g_mutex_lock(&decoder->queues_mutex);
    -    g_queue_push_tail(decoder->decoding_queue, gst_frame);
    -    g_mutex_unlock(&decoder->queues_mutex);
    +    if (decoder->appsink != NULL) {
    +        SpiceGstFrame *gst_frame = create_gst_frame(buffer, frame);
    +        g_mutex_lock(&decoder->queues_mutex);
    +        g_queue_push_tail(decoder->decoding_queue, gst_frame);
    +        g_mutex_unlock(&decoder->queues_mutex);
    +    } else {
    +        frame->free(frame);
    +        frame = NULL;
    +    }
              

So, what I mean is that we might not need to check for
decoder->appsink anymore but I don't follow why and why this
patch is removing it.

> > > -        SpiceGstFrame *gst_frame = create_gst_frame(buffer, frame);
> > > -        g_mutex_lock(&decoder->queues_mutex);
> > > -        g_queue_push_tail(decoder->decoding_queue, gst_frame);
> > > -        g_mutex_unlock(&decoder->queues_mutex);
> > > -    }
> > > +    SpiceGstFrame *gst_frame = create_gst_frame(buffer, frame);
> > > +    g_mutex_lock(&decoder->queues_mutex);
> > > +    g_queue_push_tail(decoder->decoding_queue, gst_frame);
> > > +    g_mutex_unlock(&decoder->queues_mutex);
> > 
> > Cheers,
> > Victor
> > 
> > >  
> > >      if (gst_app_src_push_buffer(decoder->appsrc, buffer) != GST_FLOW_OK) {
> > >          SPICE_DEBUG("GStreamer error: unable to push frame");
> > > diff --git a/src/channel-display-priv.h b/src/channel-display-priv.h
> > > index c5c3f5c8..495df7ac 100644
> > > --- a/src/channel-display-priv.h
> > > +++ b/src/channel-display-priv.h
> > > @@ -45,6 +45,9 @@ struct SpiceFrame {
> > >      uint8_t *data;
> > >      uint32_t size;
> > >      gpointer data_opaque;
> > > +
> > > +    /* stats */
> > > +    gint64 creation_time;
> > >  };
> > >  
> > >  typedef struct VideoDecoder VideoDecoder;
> > > diff --git a/src/channel-display.c b/src/channel-display.c
> > > index ae2c4fbc..d46b3a37 100644
> > > --- a/src/channel-display.c
> > > +++ b/src/channel-display.c
> > > @@ -1657,6 +1657,7 @@ static SpiceFrame *spice_frame_new(display_stream
> > > *st,
> > >      frame->size = data_size;
> > >      frame->data_opaque = in;
> > >      spice_msg_in_ref(in);
> > > +    frame->creation_time = g_get_monotonic_time();
> > >      return frame;
> > >  }
> > >  
> 
> Frediano
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