ts/standalone: multiple improvements

- Reworked buffer push.
- Reworked stats.
- Make first elements logs stand out. This make it possible to
  follow what's going on with pipelines containing 1000s of
  elements.
- Actually handle EOS.
- Use more significant defaults.
- Allow building without `clap` feature.

5 files changed, 685 insertions, 335 deletions

diff --git a/generic/threadshare/Cargo.toml b/generic/threadshare/Cargo.toml
index 8a34d3336..80ae0deab 100644
--- a/generic/threadshare/Cargo.toml
+++ b/generic/threadshare/Cargo.toml
@@ -54,9 +54,8 @@ name = "tcpclientsrc-benchmark-sender"
 path = "examples/tcpclientsrc_benchmark_sender.rs"
 
 [[example]]
-name = "standalone"
+name = "ts-standalone"
 path = "examples/standalone/main.rs"
-required-features = ["clap"]
 
 [build-dependencies]
 gst-plugin-version-helper = { path="../../version-helper" }
diff --git a/generic/threadshare/examples/standalone/main.rs b/generic/threadshare/examples/standalone/main.rs
index 1b14bc62e..8852d9f72 100644
--- a/generic/threadshare/examples/standalone/main.rs
+++ b/generic/threadshare/examples/standalone/main.rs
@@ -31,14 +31,18 @@ gst::plugin_define!(
     env!("BUILD_REL_DATE")
 );
 
+#[cfg(feature = "clap")]
 use clap::Parser;
 
+#[cfg(feature = "clap")]
 #[derive(Parser, Debug)]
 #[clap(version)]
-#[clap(about = "Standalone pipeline threadshare runtime test")]
+#[clap(
+    about = "Standalone pipeline threadshare runtime test. Use `GST_DEBUG=ts-standalone*:4` for stats"
+)]
 struct Args {
     /// Parallel streams to process.
-    #[clap(short, long, default_value_t = 100)]
+    #[clap(short, long, default_value_t = 5000)]
     streams: u32,
 
     /// Threadshare groups.
@@ -49,13 +53,67 @@ struct Args {
     #[clap(short, long, default_value_t = 20)]
     wait: u32,
 
+    /// Buffer push period in ms.
+    #[clap(short, long, default_value_t = 20)]
+    push_period: u32,
+
     /// Number of buffers per stream to output before sending EOS (-1 = unlimited).
-    #[clap(short, long, default_value_t = 6000)]
+    #[clap(short, long, default_value_t = 5000)]
     num_buffers: i32,
 
-    /// Enables statistics logging (use GST_DEBUG=ts-standalone*:4).
+    /// Disables statistics logging.
     #[clap(short, long)]
-    log_stats: bool,
+    disable_stats_log: bool,
+}
+
+#[cfg(not(feature = "clap"))]
+#[derive(Debug)]
+struct Args {
+    streams: u32,
+    groups: u32,
+    wait: u32,
+    push_period: u32,
+    num_buffers: i32,
+    disable_stats_log: bool,
+}
+
+#[cfg(not(feature = "clap"))]
+impl Default for Args {
+    fn default() -> Self {
+        Args {
+            streams: 5000,
+            groups: 2,
+            wait: 20,
+            push_period: 20,
+            num_buffers: 5000,
+            disable_stats_log: false,
+        }
+    }
+}
+
+fn args() -> Args {
+    #[cfg(feature = "clap")]
+    let args = {
+        let args = Args::parse();
+        gst::info!(CAT, "{:?}", args);
+
+        args
+    };
+
+    #[cfg(not(feature = "clap"))]
+    let args = {
+        if std::env::args().len() > 1 {
+            gst::warning!(CAT, "Ignoring command line arguments");
+            gst::warning!(CAT, "Build with `--features=clap`");
+        }
+
+        let args = Args::default();
+        gst::warning!(CAT, "{:?}", args);
+
+        args
+    };
+
+    args
 }
 
 fn main() {
@@ -68,7 +126,7 @@ fn main() {
     #[cfg(debug_assertions)]
     gst::warning!(CAT, "RUNNING DEBUG BUILD");
 
-    let args = Args::parse();
+    let args = args();
 
     let pipeline = gst::Pipeline::new(None);
 
@@ -82,6 +140,7 @@ fn main() {
         .unwrap();
         src.set_property("context", &ctx_name);
         src.set_property("context-wait", args.wait);
+        src.set_property("push-period", args.push_period);
         src.set_property("num-buffers", args.num_buffers);
 
         let sink = gst::ElementFactory::make(
@@ -91,8 +150,27 @@ fn main() {
         .unwrap();
         sink.set_property("context", &ctx_name);
         sink.set_property("context-wait", args.wait);
-        if i == 0 && args.log_stats {
-            sink.set_property("must-log-stats", true);
+
+        if i == 0 {
+            src.set_property("raise-log-level", true);
+            sink.set_property("raise-log-level", true);
+
+            if !args.disable_stats_log {
+                // Don't use the last 5 secs in stats
+                // otherwise we get outliers when reaching EOS.
+                // Note that stats don't start before the 20 first seconds
+                // and we get 50 buffers per sec.
+                const BUFFERS_BEFORE_LOGS: i32 = 20 * 50;
+                const BUFFERS_TO_SKIP: i32 = BUFFERS_BEFORE_LOGS + 5 * 50;
+                if args.num_buffers > BUFFERS_TO_SKIP {
+                    sink.set_property("push-period", args.push_period);
+                    sink.set_property("logs-stats", true);
+                    let max_buffers = args.num_buffers - BUFFERS_TO_SKIP;
+                    sink.set_property("max-buffers", max_buffers);
+                } else {
+                    gst::warning!(CAT, "Not enough buffers to log, disabling stats");
+                }
+            }
         }
 
         let elements = &[&src, &sink];
@@ -109,11 +187,8 @@ fn main() {
         use gst::MessageView;
 
         match msg.view() {
-            MessageView::Eos(..) => {
-                gst::info!(CAT, "Shuting down");
-                let stop = Instant::now();
-                pipeline_clone.set_state(gst::State::Null).unwrap();
-                gst::info!(CAT, "Shuting down took {:.2?}", stop.elapsed());
+            MessageView::Eos(_) => {
+                gst::info!(CAT, "Received eos");
                 l_clone.quit();
             }
             MessageView::Error(err) => {
@@ -133,10 +208,25 @@ fn main() {
     })
     .expect("Failed to add bus watch");
 
-    gst::info!(CAT, "Starting");
+    gst::info!(CAT, "Switching to Ready");
+    let start = Instant::now();
+    pipeline.set_state(gst::State::Ready).unwrap();
+    gst::info!(CAT, "Switching to Ready took {:.2?}", start.elapsed());
+
+    gst::info!(CAT, "Switching to Playing");
     let start = Instant::now();
     pipeline.set_state(gst::State::Playing).unwrap();
-    gst::info!(CAT, "Starting took {:.2?}", start.elapsed());
+    gst::info!(CAT, "Switching to Playing took {:.2?}", start.elapsed());
 
     l.run();
+
+    gst::info!(CAT, "Switching to Ready");
+    let stop = Instant::now();
+    pipeline_clone.set_state(gst::State::Ready).unwrap();
+    gst::info!(CAT, "Switching to Ready took {:.2?}", stop.elapsed());
+
+    gst::info!(CAT, "Shutting down");
+    let stop = Instant::now();
+    pipeline_clone.set_state(gst::State::Null).unwrap();
+    gst::info!(CAT, "Shutting down took {:.2?}", stop.elapsed());
 }
diff --git a/generic/threadshare/examples/standalone/sink/imp.rs b/generic/threadshare/examples/standalone/sink/imp.rs
index d2083037b..67ab406d1 100644
--- a/generic/threadshare/examples/standalone/sink/imp.rs
+++ b/generic/threadshare/examples/standalone/sink/imp.rs
@@ -10,18 +10,17 @@ use futures::future::BoxFuture;
 use futures::prelude::*;
 use futures::stream::Peekable;
 
+use gst::error_msg;
 use gst::glib;
 use gst::prelude::*;
 use gst::subclass::prelude::*;
 use gst::EventView;
-use gst::{element_error, error_msg};
 
 use once_cell::sync::Lazy;
 
 use gstthreadshare::runtime::prelude::*;
-use gstthreadshare::runtime::{self, Context, PadSink, PadSinkRef, Task};
+use gstthreadshare::runtime::{Context, PadSink, PadSinkRef, Task};
 
-use std::pin::Pin;
 use std::sync::Mutex;
 use std::task::Poll;
 use std::time::{Duration, Instant};
@@ -36,32 +35,36 @@ static CAT: Lazy<gst::DebugCategory> = Lazy::new(|| {
 
 const DEFAULT_CONTEXT: &str = "";
 const DEFAULT_CONTEXT_WAIT: Duration = Duration::from_millis(20);
-const DEFAULT_SYNC: bool = true;
-const DEFAULT_MUST_LOG_STATS: bool = false;
+const DEFAULT_PUSH_PERIOD: Duration = Duration::from_millis(20);
+const DEFAULT_MAX_BUFFERS: i32 = 50 * (100 - 25);
 
 const LOG_PERIOD: Duration = Duration::from_secs(20);
 
 #[derive(Debug, Clone)]
 struct Settings {
-    sync: bool,
     context: String,
     context_wait: Duration,
-    must_log_stats: bool,
+    raise_log_level: bool,
+    logs_stats: bool,
+    push_period: Duration,
+    max_buffers: Option<u32>,
 }
 
 impl Default for Settings {
     fn default() -> Self {
         Settings {
-            sync: DEFAULT_SYNC,
             context: DEFAULT_CONTEXT.into(),
             context_wait: DEFAULT_CONTEXT_WAIT,
-            must_log_stats: DEFAULT_MUST_LOG_STATS,
+            raise_log_level: false,
+            logs_stats: false,
+            push_period: DEFAULT_PUSH_PERIOD,
+            max_buffers: Some(DEFAULT_MAX_BUFFERS as u32),
         }
     }
 }
 
 #[derive(Debug)]
-enum TaskItem {
+enum StreamItem {
     Buffer(gst::Buffer),
     Event(gst::Event),
 }
@@ -83,7 +86,7 @@ impl PadSinkHandler for TestSinkPadHandler {
         let element = element.clone().downcast::<super::TestSink>().unwrap();
 
         async move {
-            if sender.send_async(TaskItem::Buffer(buffer)).await.is_err() {
+            if sender.send_async(StreamItem::Buffer(buffer)).await.is_err() {
                 gst::debug!(CAT, obj: &element, "Flushing");
                 return Err(gst::FlowError::Flushing);
             }
@@ -105,7 +108,7 @@ impl PadSinkHandler for TestSinkPadHandler {
 
         async move {
             for buffer in list.iter_owned() {
-                if sender.send_async(TaskItem::Buffer(buffer)).await.is_err() {
+                if sender.send_async(StreamItem::Buffer(buffer)).await.is_err() {
                     gst::debug!(CAT, obj: &element, "Flushing");
                     return Err(gst::FlowError::Flushing);
                 }
@@ -130,7 +133,7 @@ impl PadSinkHandler for TestSinkPadHandler {
             if let EventView::FlushStop(_) = event.view() {
                 let test_sink = element.imp();
                 return test_sink.task.flush_stop().await_maybe_on_context().is_ok();
-            } else if sender.send_async(TaskItem::Event(event)).await.is_err() {
+            } else if sender.send_async(StreamItem::Event(event)).await.is_err() {
                 gst::debug!(CAT, obj: &element, "Flushing");
             }
 
@@ -161,20 +164,31 @@ impl PadSinkHandler for TestSinkPadHandler {
 #[derive(Default)]
 struct Stats {
     must_log: bool,
-    sync: bool,
     ramp_up_instant: Option<Instant>,
     log_start_instant: Option<Instant>,
     last_delta_instant: Option<Instant>,
-    buffer_count: u32,
-    buffer_count_delta: u32,
-    buffer_headroom: Duration,
-    buffer_headroom_delta: Duration,
-    late_buffer_count: u32,
-    lateness: Duration,
-    max_lateness: Duration,
-    late_buffer_count_delta: u32,
-    lateness_delta: Duration,
-    max_lateness_delta: Duration,
+    max_buffers: Option<f32>,
+    buffer_count: f32,
+    buffer_count_delta: f32,
+    latency_sum: f32,
+    latency_square_sum: f32,
+    latency_sum_delta: f32,
+    latency_square_sum_delta: f32,
+    latency_min: Duration,
+    latency_min_delta: Duration,
+    latency_max: Duration,
+    latency_max_delta: Duration,
+    interval_sum: f32,
+    interval_square_sum: f32,
+    interval_sum_delta: f32,
+    interval_square_sum_delta: f32,
+    interval_min: Duration,
+    interval_min_delta: Duration,
+    interval_max: Duration,
+    interval_max_delta: Duration,
+    interval_late_warn: Duration,
+    interval_late_count: f32,
+    interval_late_count_delta: f32,
 }
 
 impl Stats {
@@ -183,24 +197,34 @@ impl Stats {
             return;
         }
 
-        self.buffer_count = 0;
-        self.buffer_count_delta = 0;
-        self.buffer_headroom = Duration::ZERO;
-        self.buffer_headroom_delta = Duration::ZERO;
-        self.late_buffer_count = 0;
-        self.lateness = Duration::ZERO;
-        self.max_lateness = Duration::ZERO;
-        self.late_buffer_count_delta = 0;
-        self.lateness_delta = Duration::ZERO;
-        self.max_lateness_delta = Duration::ZERO;
+        self.buffer_count = 0.0;
+        self.buffer_count_delta = 0.0;
+        self.latency_sum = 0.0;
+        self.latency_square_sum = 0.0;
+        self.latency_sum_delta = 0.0;
+        self.latency_square_sum_delta = 0.0;
+        self.latency_min = Duration::MAX;
+        self.latency_min_delta = Duration::MAX;
+        self.latency_max = Duration::ZERO;
+        self.latency_max_delta = Duration::ZERO;
+        self.interval_sum = 0.0;
+        self.interval_square_sum = 0.0;
+        self.interval_sum_delta = 0.0;
+        self.interval_square_sum_delta = 0.0;
+        self.interval_min = Duration::MAX;
+        self.interval_min_delta = Duration::MAX;
+        self.interval_max = Duration::ZERO;
+        self.interval_max_delta = Duration::ZERO;
+        self.interval_late_count = 0.0;
+        self.interval_late_count_delta = 0.0;
         self.last_delta_instant = None;
         self.log_start_instant = None;
 
         self.ramp_up_instant = Some(Instant::now());
-        gst::info!(CAT, "First stats logs in {:.2?}", 2 * LOG_PERIOD);
+        gst::info!(CAT, "First stats logs in {:2?}", 2 * LOG_PERIOD);
     }
 
-    fn can_count(&mut self) -> bool {
+    fn is_active(&mut self) -> bool {
         if !self.must_log {
             return false;
         }
@@ -211,53 +235,64 @@ impl Stats {
             }
 
             self.ramp_up_instant = None;
-            gst::info!(CAT, "Ramp up complete. Stats logs in {:.2?}", LOG_PERIOD);
+            gst::info!(CAT, "Ramp up complete. Stats logs in {:2?}", LOG_PERIOD);
             self.log_start_instant = Some(Instant::now());
             self.last_delta_instant = self.log_start_instant;
         }
 
-        true
+        use std::cmp::Ordering::*;
+        match self.max_buffers.opt_cmp(self.buffer_count) {
+            Some(Equal) => {
+                self.log_global();
+                self.buffer_count += 1.0;
+                false
+            }
+            Some(Less) => false,
+            _ => true,
+        }
     }
 
-    fn notify_buffer(&mut self) {
-        if !self.can_count() {
+    fn add_buffer(&mut self, latency: Duration, interval: Duration) {
+        if !self.is_active() {
             return;
         }
 
-        self.buffer_count += 1;
-        self.buffer_count_delta += 1;
-    }
+        self.buffer_count += 1.0;
+        self.buffer_count_delta += 1.0;
 
-    fn notify_buffer_headroom(&mut self, headroom: Duration) {
-        if !self.can_count() {
-            return;
-        }
+        // Latency
+        let latency_f32 = latency.as_nanos() as f32;
+        let latency_square = latency_f32.powi(2);
 
-        self.buffer_headroom += headroom;
-        self.buffer_headroom_delta += headroom;
-    }
+        self.latency_sum += latency_f32;
+        self.latency_square_sum += latency_square;
+        self.latency_min = self.latency_min.min(latency);
+        self.latency_max = self.latency_max.max(latency);
 
-    fn notify_late_buffer(&mut self, now: Option<gst::ClockTime>, pts: gst::ClockTime) {
-        if !self.can_count() {
-            return;
-        }
+        self.latency_sum_delta += latency_f32;
+        self.latency_square_sum_delta += latency_square;
+        self.latency_min_delta = self.latency_min_delta.min(latency);
+        self.latency_max_delta = self.latency_max_delta.max(latency);
 
-        let lateness = now
-            .opt_checked_sub(pts)
-            .ok()
-            .flatten()
-            .map_or(Duration::ZERO, Duration::from);
+        // Interval
+        let interval_f32 = interval.as_nanos() as f32;
+        let interval_square = interval_f32.powi(2);
 
-        self.late_buffer_count += 1;
-        self.lateness += lateness;
-        self.max_lateness = self.max_lateness.max(lateness);
+        self.interval_sum += interval_f32;
+        self.interval_square_sum += interval_square;
+        self.interval_min = self.interval_min.min(interval);
+        self.interval_max = self.interval_max.max(interval);
 
-        self.late_buffer_count_delta += 1;
-        self.lateness_delta += lateness;
-        self.max_lateness_delta = self.max_lateness_delta.max(lateness);
-    }
+        self.interval_sum_delta += interval_f32;
+        self.interval_square_sum_delta += interval_square;
+        self.interval_min_delta = self.interval_min_delta.min(interval);
+        self.interval_max_delta = self.interval_max_delta.max(interval);
+
+        if interval > self.interval_late_warn {
+            self.interval_late_count += 1.0;
+            self.interval_late_count_delta += 1.0;
+        }
 
-    fn log_delta(&mut self) {
         let delta_duration = match self.last_delta_instant {
             Some(last_delta) => last_delta.elapsed(),
             None => return,
@@ -269,94 +304,121 @@ impl Stats {
 
         self.last_delta_instant = Some(Instant::now());
 
-        gst::info!(CAT, "Delta stats:");
-        gst::info!(
-            CAT,
-            "o {:>5.2} buffers / s",
-            self.buffer_count_delta as f32 / delta_duration.as_millis() as f32 * 1_000f32,
-        );
-
-        if self.sync && self.buffer_count_delta > 0 {
-            let early_buffers_count = self
-                .buffer_count_delta
-                .saturating_sub(self.late_buffer_count_delta);
-            if early_buffers_count > 0 {
-                gst::info!(
-                    CAT,
-                    "o {:>5.2?} headroom / early buffers",
-                    self.buffer_headroom_delta / early_buffers_count,
-                );
+        if self.buffer_count_delta > 1.0 {
+            gst::info!(CAT, "Delta stats:");
 
-                gst::info!(
+            let interval_mean = self.interval_sum_delta / self.buffer_count_delta;
+            let interval_std_dev = f32::sqrt(
+                self.interval_square_sum_delta / self.buffer_count_delta - interval_mean.powi(2),
+            );
+
+            gst::info!(
+                CAT,
+                "o interval: mean {:4.2?} σ {:4.1?} [{:4.1?}, {:4.1?}]",
+                Duration::from_nanos(interval_mean as u64),
+                Duration::from_nanos(interval_std_dev as u64),
+                self.interval_min_delta,
+                self.interval_max_delta,
+            );
+
+            if self.interval_late_count_delta > 1.0 {
+                gst::warning!(
                     CAT,
-                    "o {:>5.2}% late buffers - mean {:>5.2?}, max {:>5.2?}",
-                    self.late_buffer_count_delta as f32 / self.buffer_count_delta as f32 * 100f32,
-                    self.lateness_delta
-                        .checked_div(self.late_buffer_count_delta)
-                        .unwrap_or(Duration::ZERO),
-                    self.max_lateness_delta,
+                    "o {:5.2}% late buffers",
+                    100f32 * self.interval_late_count_delta / self.buffer_count_delta
                 );
             }
 
-            self.buffer_headroom_delta = Duration::ZERO;
-            self.late_buffer_count_delta = 0;
-            self.lateness_delta = Duration::ZERO;
-            self.max_lateness_delta = Duration::ZERO;
+            self.interval_sum_delta = 0.0;
+            self.interval_square_sum_delta = 0.0;
+            self.interval_min_delta = Duration::MAX;
+            self.interval_max_delta = Duration::ZERO;
+            self.interval_late_count_delta = 0.0;
+
+            let latency_mean = self.latency_sum_delta / self.buffer_count_delta;
+            let latency_std_dev = f32::sqrt(
+                self.latency_square_sum_delta / self.buffer_count_delta - latency_mean.powi(2),
+            );
+
+            gst::info!(
+                CAT,
+                "o latency: mean {:4.2?} σ {:4.1?} [{:4.1?}, {:4.1?}]",
+                Duration::from_nanos(latency_mean as u64),
+                Duration::from_nanos(latency_std_dev as u64),
+                self.latency_min_delta,
+                self.latency_max_delta,
+            );
+
+            self.latency_sum_delta = 0.0;
+            self.latency_square_sum_delta = 0.0;
+            self.latency_min_delta = Duration::MAX;
+            self.latency_max_delta = Duration::ZERO;
         }
 
-        self.buffer_count_delta = 0;
+        self.buffer_count_delta = 0.0;
     }
 
     fn log_global(&mut self) {
-        let log_duration = match self.log_start_instant {
-            Some(start) => start.elapsed(),
-            None => return,
-        };
+        if self.log_start_instant.is_none() {
+            return;
+        }
 
-        gst::info!(CAT, "Global stats:");
-        gst::info!(
-            CAT,
-            "o {:>5.2} buffers / s",
-            self.buffer_count as f32 / log_duration.as_millis() as f32 * 1_000f32,
-        );
-
-        if self.sync && self.buffer_count > 0 {
-            let early_buffers_count = self.buffer_count.saturating_sub(self.late_buffer_count);
-            if early_buffers_count > 0 {
-                gst::info!(
-                    CAT,
-                    "o {:>5.2?} headroom / early buffers",
-                    self.buffer_headroom / early_buffers_count,
-                );
+        if self.buffer_count > 1.0 {
+            gst::info!(CAT, "Global stats:");
 
-                gst::info!(
+            let interval_mean = self.interval_sum / self.buffer_count;
+            let interval_std_dev =
+                f32::sqrt(self.interval_square_sum / self.buffer_count - interval_mean.powi(2));
+
+            gst::info!(
+                CAT,
+                "o interval: mean {:4.2?} σ {:4.1?} [{:4.1?}, {:4.1?}]",
+                Duration::from_nanos(interval_mean as u64),
+                Duration::from_nanos(interval_std_dev as u64),
+                self.interval_min,
+                self.interval_max,
+            );
+
+            if self.interval_late_count > f32::EPSILON {
+                gst::warning!(
                     CAT,
-                    "o {:>5.2}% late buffers - mean {:>5.2?}, max {:>5.2?}",
-                    self.late_buffer_count as f32 / self.buffer_count as f32 * 100f32,
-                    self.lateness
-                        .checked_div(self.late_buffer_count)
-                        .unwrap_or(Duration::ZERO),
-                    self.max_lateness,
+                    "o {:5.2}% late buffers",
+                    100f32 * self.interval_late_count / self.buffer_count
                 );
             }
+
+            let latency_mean = self.latency_sum / self.buffer_count;
+            let latency_std_dev =
+                f32::sqrt(self.latency_square_sum / self.buffer_count - latency_mean.powi(2));
+
+            gst::info!(
+                CAT,
+                "o latency: mean {:4.2?} σ {:4.1?} [{:4.1?}, {:4.1?}]",
+                Duration::from_nanos(latency_mean as u64),
+                Duration::from_nanos(latency_std_dev as u64),
+                self.latency_min,
+                self.latency_max,
+            );
         }
     }
 }
 
 struct TestSinkTask {
     element: super::TestSink,
-    item_receiver: Peekable<flume::r#async::RecvStream<'static, TaskItem>>,
-    sync: bool,
+    raise_log_level: bool,
+    last_dts: Option<gst::ClockTime>,
+    item_receiver: Peekable<flume::r#async::RecvStream<'static, StreamItem>>,
     stats: Stats,
     segment: Option<gst::Segment>,
 }
 
 impl TestSinkTask {
-    fn new(element: &super::TestSink, item_receiver: flume::Receiver<TaskItem>) -> Self {
+    fn new(element: &super::TestSink, item_receiver: flume::Receiver<StreamItem>) -> Self {
         TestSinkTask {
             element: element.clone(),
+            raise_log_level: false,
+            last_dts: None,
             item_receiver: item_receiver.into_stream().peekable(),
-            sync: DEFAULT_SYNC,
             stats: Stats::default(),
             segment: None,
         }
@@ -369,17 +431,23 @@ impl TestSinkTask {
 }
 
 impl TaskImpl for TestSinkTask {
-    type Item = TaskItem;
+    type Item = StreamItem;
 
     fn prepare(&mut self) -> BoxFuture<'_, Result<(), gst::ErrorMessage>> {
         async move {
-            gst::log!(CAT, obj: &self.element, "Preparing Task");
-
             let sink = self.element.imp();
             let settings = sink.settings.lock().unwrap();
-            self.sync = settings.sync;
-            self.stats.sync = self.sync;
-            self.stats.must_log = settings.must_log_stats;
+            self.raise_log_level = settings.raise_log_level;
+
+            if self.raise_log_level {
+                gst::log!(CAT, obj: &self.element, "Preparing Task");
+            } else {
+                gst::trace!(CAT, obj: &self.element, "Preparing Task");
+            }
+
+            self.stats.must_log = settings.logs_stats;
+            self.stats.max_buffers = settings.max_buffers.map(|max_buffers| max_buffers as f32);
+            self.stats.interval_late_warn = settings.push_period + settings.context_wait / 2;
 
             Ok(())
         }
@@ -388,7 +456,13 @@ impl TaskImpl for TestSinkTask {
 
     fn start(&mut self) -> BoxFuture<'_, Result<(), gst::ErrorMessage>> {
         async {
-            gst::log!(CAT, obj: &self.element, "Starting Task");
+            if self.raise_log_level {
+                gst::log!(CAT, obj: &self.element, "Starting Task");
+            } else {
+                gst::trace!(CAT, obj: &self.element, "Starting Task");
+            }
+
+            self.last_dts = None;
             self.stats.start();
             Ok(())
         }
@@ -397,81 +471,92 @@ impl TaskImpl for TestSinkTask {
 
     fn stop(&mut self) -> BoxFuture<'_, Result<(), gst::ErrorMessage>> {
         async {
-            gst::log!(CAT, obj: &self.element, "Stopping Task");
-            self.flush().await;
-            Ok(())
-        }
-        .boxed()
-    }
+            if self.raise_log_level {
+                gst::log!(CAT, obj: &self.element, "Stopping Task");
+            } else {
+                gst::trace!(CAT, obj: &self.element, "Stopping Task");
+            }
 
-    fn flush_start(&mut self) -> BoxFuture<'_, Result<(), gst::ErrorMessage>> {
-        async {
-            gst::log!(CAT, obj: &self.element, "Starting Task Flush");
             self.flush().await;
             Ok(())
         }
         .boxed()
     }
 
-    fn try_next(&mut self) -> BoxFuture<'_, Result<TaskItem, gst::FlowError>> {
+    fn try_next(&mut self) -> BoxFuture<'_, Result<StreamItem, gst::FlowError>> {
         async move {
-            let item_opt = Pin::new(&mut self.item_receiver).peek().await;
+            let item = self.item_receiver.next().await.unwrap();
 
-            // Check the peeked item in case we need to sync.
-            // The item will still be available in the channel
-            // in case this is cancelled by a state transition.
-            match item_opt {
-                Some(TaskItem::Buffer(buffer)) => {
-                    self.stats.notify_buffer();
-
-                    if self.sync {
-                        let rtime = self.segment.as_ref().and_then(|segment| {
-                            segment
-                                .downcast_ref::<gst::format::Time>()
-                                .and_then(|segment| segment.to_running_time(buffer.pts()))
-                        });
-                        if let Some(pts) = rtime {
-                            // This can be cancelled by a state transition.
-                            self.sync(pts).await;
-                        }
-                    }
-                }
-                Some(_) => (),
-                None => {
-                    panic!("Internal channel sender dropped while Task is Started");
-                }
+            if self.raise_log_level {
+                gst::log!(CAT, obj: &self.element, "Popped item");
+            } else {
+                gst::trace!(CAT, obj: &self.element, "Popped item");
             }
 
-            // An item was peeked above, we can now pop it without losing it.
-            Ok(self.item_receiver.next().await.unwrap())
+            Ok(item)
         }
         .boxed()
     }
 
-    fn handle_item(&mut self, item: TaskItem) -> BoxFuture<'_, Result<(), gst::FlowError>> {
+    fn handle_item(&mut self, item: StreamItem) -> BoxFuture<'_, Result<(), gst::FlowError>> {
         async move {
-            gst::debug!(CAT, obj: &self.element, "Handling {:?}", item);
+            if self.raise_log_level {
+                gst::debug!(CAT, obj: &self.element, "Received {:?}", item);
+            } else {
+                gst::trace!(CAT, obj: &self.element, "Received {:?}", item);
+            }
 
             match item {
-                TaskItem::Buffer(buffer) => {
-                    self.render(buffer).await.map_err(|err| {
-                        element_error!(
-                            &self.element,
-                            gst::StreamError::Failed,
-                            ["Failed to render item, stopping task: {}", err]
-                        );
-                        gst::FlowError::Error
-                    })?;
-
-                    self.stats.log_delta();
+                StreamItem::Buffer(buffer) => {
+                    let dts = self
+                        .segment
+                        .as_ref()
+                        .and_then(|segment| {
+                            segment
+                                .downcast_ref::<gst::format::Time>()
+                                .and_then(|segment| segment.to_running_time(buffer.dts()))
+                        })
+                        .unwrap();
+
+                    if let Some(last_dts) = self.last_dts {
+                        let cur_ts = self.element.current_running_time().unwrap();
+                        let latency: Duration = (cur_ts - dts).into();
+                        let interval: Duration = (dts - last_dts).into();
+
+                        self.stats.add_buffer(latency, interval);
+
+                        if self.raise_log_level {
+                            gst::debug!(CAT, obj: &self.element, "o latency {:.2?}", latency);
+                            gst::debug!(CAT, obj: &self.element, "o interval {:.2?}", interval);
+                        } else {
+                            gst::trace!(CAT, obj: &self.element, "o latency {:.2?}", latency);
+                            gst::trace!(CAT, obj: &self.element, "o interval {:.2?}", interval);
+                        }
+                    }
+
+                    self.last_dts = Some(dts);
+
+                    if self.raise_log_level {
+                        gst::log!(CAT, obj: &self.element, "Buffer processed");
+                    } else {
+                        gst::trace!(CAT, obj: &self.element, "Buffer processed");
+                    }
                 }
-                TaskItem::Event(event) => match event.view() {
+                StreamItem::Event(event) => match event.view() {
                     EventView::Eos(_) => {
-                        self.stats.log_global();
+                        if self.raise_log_level {
+                            gst::debug!(CAT, obj: &self.element, "EOS");
+                        } else {
+                            gst::trace!(CAT, obj: &self.element, "EOS");
+                        }
 
-                        let _ = self
-                            .element
-                            .post_message(gst::message::Eos::builder().src(&self.element).build());
+                        let elem = self.element.clone();
+                        self.element.call_async(move |_| {
+                            let _ =
+                                elem.post_message(gst::message::Eos::builder().src(&elem).build());
+                        });
+
+                        return Err(gst::FlowError::Eos);
                     }
                     EventView::Segment(e) => {
                         self.segment = Some(e.segment().clone());
@@ -489,54 +574,27 @@ impl TaskImpl for TestSinkTask {
     }
 }
 
-impl TestSinkTask {
-    async fn render(&mut self, buffer: gst::Buffer) -> Result<(), gst::FlowError> {
-        let _data = buffer.map_readable().map_err(|_| {
-            element_error!(
-                self.element,
-                gst::StreamError::Format,
-                ["Failed to map buffer readable"]
-            );
-            gst::FlowError::Error
-        })?;
-
-        gst::log!(CAT, obj: &self.element, "buffer {:?} rendered", buffer);
-
-        Ok(())
-    }
-
-    /// Waits until specified time.
-    async fn sync(&mut self, pts: gst::ClockTime) {
-        let now = self.element.current_running_time();
-
-        if let Ok(Some(delay)) = pts.opt_checked_sub(now) {
-            let delay = delay.into();
-            gst::trace!(CAT, obj: &self.element, "sync: waiting {:?}", delay);
-            runtime::time::delay_for(delay).await;
-
-            self.stats.notify_buffer_headroom(delay);
-        } else {
-            self.stats.notify_late_buffer(now, pts);
-        }
-    }
-}
-
 #[derive(Debug)]
 pub struct TestSink {
     sink_pad: PadSink,
     task: Task,
-    item_sender: Mutex<Option<flume::Sender<TaskItem>>>,
+    item_sender: Mutex<Option<flume::Sender<StreamItem>>>,
     settings: Mutex<Settings>,
 }
 
 impl TestSink {
     #[track_caller]
-    fn clone_item_sender(&self) -> flume::Sender<TaskItem> {
+    fn clone_item_sender(&self) -> flume::Sender<StreamItem> {
         self.item_sender.lock().unwrap().as_ref().unwrap().clone()
     }
 
     fn prepare(&self, element: &super::TestSink) -> Result<(), gst::ErrorMessage> {
-        gst::debug!(CAT, obj: element, "Preparing");
+        let raise_log_level = self.settings.lock().unwrap().raise_log_level;
+        if raise_log_level {
+            gst::debug!(CAT, obj: element, "Preparing");
+        } else {
+            gst::trace!(CAT, obj: element, "Preparing");
+        }
 
         let context = {
             let settings = self.settings.lock().unwrap();
@@ -556,28 +614,67 @@ impl TestSink {
 
         *self.item_sender.lock().unwrap() = Some(item_sender);
 
-        gst::debug!(CAT, obj: element, "Started preparation");
+        if raise_log_level {
+            gst::debug!(CAT, obj: element, "Prepared");
+        } else {
+            gst::trace!(CAT, obj: element, "Prepared");
+        }
 
         Ok(())
     }
 
     fn unprepare(&self, element: &super::TestSink) {
-        gst::debug!(CAT, obj: element, "Unpreparing");
+        let raise_log_level = self.settings.lock().unwrap().raise_log_level;
+        if raise_log_level {
+            gst::debug!(CAT, obj: element, "Unpreparing");
+        } else {
+            gst::trace!(CAT, obj: element, "Unpreparing");
+        }
+
         self.task.unprepare().block_on().unwrap();
-        gst::debug!(CAT, obj: element, "Unprepared");
+
+        if raise_log_level {
+            gst::debug!(CAT, obj: element, "Unprepared");
+        } else {
+            gst::trace!(CAT, obj: element, "Unprepared");
+        }
     }
 
     fn stop(&self, element: &super::TestSink) -> Result<(), gst::ErrorMessage> {
-        gst::debug!(CAT, obj: element, "Stopping");
+        let raise_log_level = self.settings.lock().unwrap().raise_log_level;
+        if raise_log_level {
+            gst::debug!(CAT, obj: element, "Stopping");
+        } else {
+            gst::trace!(CAT, obj: element, "Stopping");
+        }
+
         self.task.stop().block_on()?;
-        gst::debug!(CAT, obj: element, "Stopped");
+
+        if raise_log_level {
+            gst::debug!(CAT, obj: element, "Stopped");
+        } else {
+            gst::trace!(CAT, obj: element, "Stopped");
+        }
+
         Ok(())
     }
 
     fn start(&self, element: &super::TestSink) -> Result<(), gst::ErrorMessage> {
-        gst::debug!(CAT, obj: element, "Starting");
+        let raise_log_level = self.settings.lock().unwrap().raise_log_level;
+        if raise_log_level {
+            gst::debug!(CAT, obj: element, "Starting");
+        } else {
+            gst::trace!(CAT, obj: element, "Starting");
+        }
+
         self.task.start().block_on()?;
-        gst::debug!(CAT, obj: element, "Started");
+
+        if raise_log_level {
+            gst::debug!(CAT, obj: element, "Started");
+        } else {
+            gst::trace!(CAT, obj: element, "Started");
+        }
+
         Ok(())
     }
 }
@@ -616,17 +713,27 @@ impl ObjectImpl for TestSink {
                     .maximum(1000)
                     .default_value(DEFAULT_CONTEXT_WAIT.as_millis() as u32)
                     .build(),
-                glib::ParamSpecBoolean::builder("sync")
-                    .nick("Sync")
-                    .blurb("Sync on the clock")
-                    .default_value(DEFAULT_SYNC)
+                glib::ParamSpecBoolean::builder("raise-log-level")
+                    .nick("Raise log level")
+                    .blurb("Raises the log level so that this element stands out")
+                    .write_only()
                     .build(),
-                glib::ParamSpecBoolean::builder("must-log-stats")
-                    .nick("Must Log Stats")
+                glib::ParamSpecBoolean::builder("logs-stats")
+                    .nick("Logs Stats")
                     .blurb("Whether statistics should be logged")
-                    .default_value(DEFAULT_MUST_LOG_STATS)
                     .write_only()
                     .build(),
+                glib::ParamSpecUInt::builder("push-period")
+                    .nick("Src buffer Push Period")
+                    .blurb("Push period used by `src` element (used for stats warnings)")
+                    .default_value(DEFAULT_PUSH_PERIOD.as_millis() as u32)
+                    .build(),
+                glib::ParamSpecInt::builder("max-buffers")
+                    .nick("Max Buffers")
+                    .blurb("Number of buffers to count before stopping stats (-1 = unlimited)")
+                    .minimum(-1i32)
+                    .default_value(DEFAULT_MAX_BUFFERS)
+                    .build(),
             ]
         });
 
@@ -642,10 +749,6 @@ impl ObjectImpl for TestSink {
     ) {
         let mut settings = self.settings.lock().unwrap();
         match pspec.name() {
-            "sync" => {
-                let sync = value.get().expect("type checked upstream");
-                settings.sync = sync;
-            }
             "context" => {
                 settings.context = value
                     .get::<Option<String>>()
@@ -657,9 +760,21 @@ impl ObjectImpl for TestSink {
                     value.get::<u32>().expect("type checked upstream").into(),
                 );
             }
-            "must-log-stats" => {
-                let must_log_stats = value.get().expect("type checked upstream");
-                settings.must_log_stats = must_log_stats;
+            "raise-log-level" => {
+                settings.raise_log_level = value.get::<bool>().expect("type checked upstream");
+            }
+            "logs-stats" => {
+                let logs_stats = value.get().expect("type checked upstream");
+                settings.logs_stats = logs_stats;
+            }
+            "push-period" => {
+                settings.push_period = Duration::from_millis(
+                    value.get::<u32>().expect("type checked upstream").into(),
+                );
+            }
+            "max-buffers" => {
+                let value = value.get::<i32>().expect("type checked upstream");
+                settings.max_buffers = if value > 0 { Some(value as u32) } else { None };
             }
             _ => unimplemented!(),
         }
@@ -668,9 +783,15 @@ impl ObjectImpl for TestSink {
     fn property(&self, _obj: &Self::Type, _id: usize, pspec: &glib::ParamSpec) -> glib::Value {
         let settings = self.settings.lock().unwrap();
         match pspec.name() {
-            "sync" => settings.sync.to_value(),
             "context" => settings.context.to_value(),
             "context-wait" => (settings.context_wait.as_millis() as u32).to_value(),
+            "raise-log-level" => settings.raise_log_level.to_value(),
+            "push-period" => (settings.push_period.as_millis() as u32).to_value(),
+            "max-buffers" => settings
+                .max_buffers
+                .and_then(|val| val.try_into().ok())
+                .unwrap_or(-1i32)
+                .to_value(),
             _ => unimplemented!(),
         }
     }
diff --git a/generic/threadshare/examples/standalone/src/imp.rs b/generic/threadshare/examples/standalone/src/imp.rs
index 6b5f1d426..afcb2c418 100644
--- a/generic/threadshare/examples/standalone/src/imp.rs
+++ b/generic/threadshare/examples/standalone/src/imp.rs
@@ -16,7 +16,7 @@ use gst::subclass::prelude::*;
 use once_cell::sync::Lazy;
 
 use std::sync::Mutex;
-use std::time::{Duration, Instant};
+use std::time::Duration;
 
 use gstthreadshare::runtime::prelude::*;
 use gstthreadshare::runtime::{Context, PadSrc, Task, Timer};
@@ -29,17 +29,18 @@ static CAT: Lazy<gst::DebugCategory> = Lazy::new(|| {
     )
 });
 
-const BUFFER_DURATION: gst::ClockTime = gst::ClockTime::from_mseconds(20);
-
 const DEFAULT_CONTEXT: &str = "";
 const DEFAULT_CONTEXT_WAIT: Duration = Duration::from_millis(20);
-const DEFAULT_NUM_BUFFERS: i32 = 50 * 60 * 2;
+const DEFAULT_PUSH_PERIOD: gst::ClockTime = gst::ClockTime::from_mseconds(20);
+const DEFAULT_NUM_BUFFERS: i32 = 50 * 100;
 
 #[derive(Debug, Clone)]
 struct Settings {
     context: String,
     context_wait: Duration,
-    num_buffers: Option<i32>,
+    push_period: gst::ClockTime,
+    raise_log_level: bool,
+    num_buffers: Option<u32>,
 }
 
 impl Default for Settings {
@@ -47,7 +48,9 @@ impl Default for Settings {
         Settings {
             context: DEFAULT_CONTEXT.into(),
             context_wait: DEFAULT_CONTEXT_WAIT,
-            num_buffers: Some(DEFAULT_NUM_BUFFERS),
+            push_period: DEFAULT_PUSH_PERIOD,
+            raise_log_level: false,
+            num_buffers: Some(DEFAULT_NUM_BUFFERS as u32),
         }
     }
 }
@@ -62,13 +65,13 @@ impl PadSrcHandler for TestSrcPadHandler {
 struct SrcTask {
     element: super::TestSrc,
     buffer_pool: gst::BufferPool,
-    last_pts: gst::ClockTime,
-    last_buf_instant: Option<Instant>,
-    push_period: Duration,
+    timer: Option<Timer>,
+    raise_log_level: bool,
+    push_period: gst::ClockTime,
     need_initial_events: bool,
     need_segment: bool,
-    num_buffers: Option<i32>,
-    buffer_count: i32,
+    num_buffers: Option<u32>,
+    buffer_count: u32,
 }
 
 impl SrcTask {
@@ -83,12 +86,12 @@ impl SrcTask {
         SrcTask {
             element,
             buffer_pool,
-            last_pts: gst::ClockTime::ZERO,
-            last_buf_instant: None,
-            push_period: Duration::ZERO,
+            timer: None,
+            raise_log_level: false,
+            push_period: gst::ClockTime::ZERO,
             need_initial_events: true,
             need_segment: true,
-            num_buffers: Some(DEFAULT_NUM_BUFFERS),
+            num_buffers: Some(DEFAULT_NUM_BUFFERS as u32),
             buffer_count: 0,
         }
     }
@@ -99,11 +102,17 @@ impl TaskImpl for SrcTask {
 
     fn prepare(&mut self) -> BoxFuture<'_, Result<(), gst::ErrorMessage>> {
         async move {
-            gst::log!(CAT, obj: &self.element, "Preparing Task");
-
             let src = self.element.imp();
             let settings = src.settings.lock().unwrap();
-            self.push_period = settings.context_wait;
+            self.raise_log_level = settings.raise_log_level;
+
+            if self.raise_log_level {
+                gst::log!(CAT, obj: &self.element, "Preparing Task");
+            } else {
+                gst::trace!(CAT, obj: &self.element, "Preparing Task");
+            }
+
+            self.push_period = settings.push_period;
             self.num_buffers = settings.num_buffers;
 
             Ok(())
@@ -113,9 +122,18 @@ impl TaskImpl for SrcTask {
 
     fn start(&mut self) -> BoxFuture<'_, Result<(), gst::ErrorMessage>> {
         async {
-            gst::log!(CAT, obj: &self.element, "Starting Task");
+            if self.raise_log_level {
+                gst::log!(CAT, obj: &self.element, "Starting Task");
+            } else {
+                gst::trace!(CAT, obj: &self.element, "Starting Task");
+            }
+
+            self.timer = Some(Timer::interval_delayed_by(
+                // Delay first buffer push so as to let others start.
+                Duration::from_secs(2),
+                self.push_period.into(),
+            ));
             self.buffer_count = 0;
-            self.last_buf_instant = None;
             self.buffer_pool.set_active(true).unwrap();
             Ok(())
         }
@@ -124,27 +142,17 @@ impl TaskImpl for SrcTask {
 
     fn stop(&mut self) -> BoxFuture<'_, Result<(), gst::ErrorMessage>> {
         async move {
-            gst::log!(CAT, obj: &self.element, "Stopping task");
+            if self.raise_log_level {
+                gst::log!(CAT, obj: &self.element, "Stopping Task");
+            } else {
+                gst::trace!(CAT, obj: &self.element, "Stopping Task");
+            }
 
             self.buffer_pool.set_active(false).unwrap();
-            self.last_pts = gst::ClockTime::ZERO;
+            self.timer = None;
             self.need_initial_events = true;
             self.need_segment = true;
 
-            gst::log!(CAT, obj: &self.element, "Task stopped");
-            Ok(())
-        }
-        .boxed()
-    }
-
-    fn flush_start(&mut self) -> BoxFuture<'_, Result<(), gst::ErrorMessage>> {
-        async move {
-            gst::log!(CAT, obj: &self.element, "Starting task flush");
-
-            self.buffer_pool.set_active(false).unwrap();
-            self.need_segment = true;
-
-            gst::log!(CAT, obj: &self.element, "Task flush started");
             Ok(())
         }
         .boxed()
@@ -152,30 +160,34 @@ impl TaskImpl for SrcTask {
 
     fn try_next(&mut self) -> BoxFuture<'_, Result<gst::Buffer, gst::FlowError>> {
         async move {
-            if let Some(delay) = self
-                .last_buf_instant
-                .map(|last| last.elapsed())
-                .opt_checked_sub(self.push_period)
-                .ok()
-                .flatten()
-            {
-                Timer::after(delay).await;
+            if self.raise_log_level {
+                gst::log!(CAT, obj: &self.element, "Awaiting timer");
+            } else {
+                gst::trace!(CAT, obj: &self.element, "Awaiting timer");
             }
 
-            self.last_buf_instant = Some(Instant::now());
-
-            let start = self.last_pts;
-            self.last_pts = start + BUFFER_DURATION;
+            self.timer.as_mut().unwrap().next().await;
 
-            self.buffer_pool.acquire_buffer(None).map(|mut buffer| {
-                {
-                    let buffer = buffer.get_mut().unwrap();
-                    buffer.set_pts(start);
-                    buffer.set_duration(BUFFER_DURATION);
-                }
+            if self.raise_log_level {
+                gst::log!(CAT, obj: &self.element, "Timer ticked");
+            } else {
+                gst::trace!(CAT, obj: &self.element, "Timer ticked");
+            }
 
-                buffer
-            })
+            self.buffer_pool
+                .acquire_buffer(None)
+                .map(|mut buffer| {
+                    {
+                        let buffer = buffer.get_mut().unwrap();
+                        let rtime = self.element.current_running_time().unwrap();
+                        buffer.set_dts(rtime);
+                    }
+                    buffer
+                })
+                .map_err(|err| {
+                    gst::error!(CAT, obj: &self.element, "Failed to acquire buffer {}", err);
+                    err
+                })
         }
         .boxed()
     }
@@ -185,15 +197,29 @@ impl TaskImpl for SrcTask {
             let res = self.push(buffer).await;
             match res {
                 Ok(_) => {
-                    gst::log!(CAT, obj: &self.element, "Successfully pushed buffer");
+                    if self.raise_log_level {
+                        gst::log!(CAT, obj: &self.element, "Successfully pushed buffer");
+                    } else {
+                        gst::trace!(CAT, obj: &self.element, "Successfully pushed buffer");
+                    }
                 }
                 Err(gst::FlowError::Eos) => {
-                    gst::debug!(CAT, obj: &self.element, "EOS");
+                    if self.raise_log_level {
+                        gst::debug!(CAT, obj: &self.element, "EOS");
+                    } else {
+                        gst::trace!(CAT, obj: &self.element, "EOS");
+                    }
                     let test_src = self.element.imp();
                     test_src.src_pad.push_event(gst::event::Eos::new()).await;
+
+                    return Err(gst::FlowError::Eos);
                 }
                 Err(gst::FlowError::Flushing) => {
-                    gst::debug!(CAT, obj: &self.element, "Flushing");
+                    if self.raise_log_level {
+                        gst::debug!(CAT, obj: &self.element, "Flushing");
+                    } else {
+                        gst::trace!(CAT, obj: &self.element, "Flushing");
+                    }
                 }
                 Err(err) => {
                     gst::error!(CAT, obj: &self.element, "Got error {}", err);
@@ -214,11 +240,20 @@ impl TaskImpl for SrcTask {
 
 impl SrcTask {
     async fn push(&mut self, buffer: gst::Buffer) -> Result<gst::FlowSuccess, gst::FlowError> {
-        gst::log!(CAT, obj: &self.element, "Handling {:?}", buffer);
+        if self.raise_log_level {
+            gst::debug!(CAT, obj: &self.element, "Pushing {:?}", buffer);
+        } else {
+            gst::trace!(CAT, obj: &self.element, "Pushing {:?}", buffer);
+        }
+
         let test_src = self.element.imp();
 
         if self.need_initial_events {
-            gst::debug!(CAT, obj: &self.element, "Pushing initial events");
+            if self.raise_log_level {
+                gst::debug!(CAT, obj: &self.element, "Pushing initial events");
+            } else {
+                gst::trace!(CAT, obj: &self.element, "Pushing initial events");
+            }
 
             let stream_id = format!("{:08x}{:08x}", rand::random::<u32>(), rand::random::<u32>());
             let stream_start_evt = gst::event::StreamStart::builder(&stream_id)
@@ -244,12 +279,27 @@ impl SrcTask {
             self.need_segment = false;
         }
 
-        gst::debug!(CAT, obj: &self.element, "Forwarding {:?}", buffer);
+        if self.raise_log_level {
+            gst::debug!(CAT, obj: &self.element, "Forwarding buffer");
+        } else {
+            gst::trace!(CAT, obj: &self.element, "Forwarding buffer");
+        }
+
         let ok = test_src.src_pad.push(buffer).await?;
 
         self.buffer_count += 1;
 
         if self.num_buffers.opt_eq(self.buffer_count).unwrap_or(false) {
+            if self.raise_log_level {
+                gst::debug!(CAT, obj: &self.element, "Pushing EOS");
+            } else {
+                gst::trace!(CAT, obj: &self.element, "Pushing EOS");
+            }
+
+            let test_src = self.element.imp();
+            if !test_src.src_pad.push_event(gst::event::Eos::new()).await {
+                gst::error!(CAT, obj: &self.element, "Error pushing EOS");
+            }
             return Err(gst::FlowError::Eos);
         }
 
@@ -266,7 +316,12 @@ pub struct TestSrc {
 
 impl TestSrc {
     fn prepare(&self, element: &super::TestSrc) -> Result<(), gst::ErrorMessage> {
-        gst::debug!(CAT, obj: element, "Preparing");
+        let raise_log_level = self.settings.lock().unwrap().raise_log_level;
+        if raise_log_level {
+            gst::debug!(CAT, obj: element, "Preparing");
+        } else {
+            gst::trace!(CAT, obj: element, "Preparing");
+        }
 
         let settings = self.settings.lock().unwrap();
         let context =
@@ -282,35 +337,86 @@ impl TestSrc {
             .prepare(SrcTask::new(element.clone()), context)
             .block_on()?;
 
-        gst::debug!(CAT, obj: element, "Prepared");
+        if raise_log_level {
+            gst::debug!(CAT, obj: element, "Prepared");
+        } else {
+            gst::trace!(CAT, obj: element, "Prepared");
+        }
 
         Ok(())
     }
 
     fn unprepare(&self, element: &super::TestSrc) {
-        gst::debug!(CAT, obj: element, "Unpreparing");
+        let raise_log_level = self.settings.lock().unwrap().raise_log_level;
+        if raise_log_level {
+            gst::debug!(CAT, obj: element, "Unpreparing");
+        } else {
+            gst::trace!(CAT, obj: element, "Unpreparing");
+        }
+
         self.task.unprepare().block_on().unwrap();
-        gst::debug!(CAT, obj: element, "Unprepared");
+
+        if raise_log_level {
+            gst::debug!(CAT, obj: element, "Unprepared");
+        } else {
+            gst::trace!(CAT, obj: element, "Unprepared");
+        }
     }
 
     fn stop(&self, element: &super::TestSrc) -> Result<(), gst::ErrorMessage> {
-        gst::debug!(CAT, obj: element, "Stopping");
+        let raise_log_level = self.settings.lock().unwrap().raise_log_level;
+        if raise_log_level {
+            gst::debug!(CAT, obj: element, "Stopping");
+        } else {
+            gst::trace!(CAT, obj: element, "Stopping");
+        }
+
         self.task.stop().block_on()?;
-        gst::debug!(CAT, obj: element, "Stopped");
+
+        if raise_log_level {
+            gst::debug!(CAT, obj: element, "Stopped");
+        } else {
+            gst::trace!(CAT, obj: element, "Stopped");
+        }
+
         Ok(())
     }
 
     fn start(&self, element: &super::TestSrc) -> Result<(), gst::ErrorMessage> {
-        gst::debug!(CAT, obj: element, "Starting");
+        let raise_log_level = self.settings.lock().unwrap().raise_log_level;
+        if raise_log_level {
+            gst::debug!(CAT, obj: element, "Starting");
+        } else {
+            gst::trace!(CAT, obj: element, "Starting");
+        }
+
         self.task.start().block_on()?;
-        gst::debug!(CAT, obj: element, "Started");
+
+        if raise_log_level {
+            gst::debug!(CAT, obj: element, "Started");
+        } else {
+            gst::trace!(CAT, obj: element, "Started");
+        }
+
         Ok(())
     }
 
     fn pause(&self, element: &super::TestSrc) -> Result<(), gst::ErrorMessage> {
-        gst::debug!(CAT, obj: element, "Pausing");
+        let raise_log_level = self.settings.lock().unwrap().raise_log_level;
+        if raise_log_level {
+            gst::debug!(CAT, obj: element, "Pausing");
+        } else {
+            gst::trace!(CAT, obj: element, "Pausing");
+        }
+
         self.task.pause().block_on()?;
-        gst::debug!(CAT, obj: element, "Paused");
+
+        if raise_log_level {
+            gst::debug!(CAT, obj: element, "Paused");
+        } else {
+            gst::trace!(CAT, obj: element, "Paused");
+        }
+
         Ok(())
     }
 }
@@ -348,6 +454,16 @@ impl ObjectImpl for TestSrc {
                     .maximum(1000)
                     .default_value(DEFAULT_CONTEXT_WAIT.as_millis() as u32)
                     .build(),
+                glib::ParamSpecUInt::builder("push-period")
+                    .nick("Buffer Push Period")
+                    .blurb("Push a new buffer every this many ms")
+                    .default_value(DEFAULT_PUSH_PERIOD.mseconds() as u32)
+                    .build(),
+                glib::ParamSpecBoolean::builder("raise-log-level")
+                    .nick("Raise log level")
+                    .blurb("Raises the log level so that this element stands out")
+                    .write_only()
+                    .build(),
                 glib::ParamSpecInt::builder("num-buffers")
                     .nick("Num Buffers")
                     .blurb("Number of buffers to output before sending EOS (-1 = unlimited)")
@@ -380,9 +496,17 @@ impl ObjectImpl for TestSrc {
                     value.get::<u32>().expect("type checked upstream").into(),
                 );
             }
+            "push-period" => {
+                settings.push_period = gst::ClockTime::from_mseconds(
+                    value.get::<u32>().expect("type checked upstream").into(),
+                );
+            }
+            "raise-log-level" => {
+                settings.raise_log_level = value.get::<bool>().expect("type checked upstream");
+            }
             "num-buffers" => {
                 let value = value.get::<i32>().expect("type checked upstream");
-                settings.num_buffers = if value > 0 { Some(value) } else { None };
+                settings.num_buffers = if value > 0 { Some(value as u32) } else { None };
             }
             _ => unimplemented!(),
         }
@@ -393,7 +517,13 @@ impl ObjectImpl for TestSrc {
         match pspec.name() {
             "context" => settings.context.to_value(),
             "context-wait" => (settings.context_wait.as_millis() as u32).to_value(),
-            "num-buffers" => settings.num_buffers.unwrap_or(-1).to_value(),
+            "push-period" => (settings.push_period.mseconds() as u32).to_value(),
+            "raise-log-level" => settings.raise_log_level.to_value(),
+            "num-buffers" => settings
+                .num_buffers
+                .and_then(|val| val.try_into().ok())
+                .unwrap_or(-1i32)
+                .to_value(),
             _ => unimplemented!(),
         }
     }
diff --git a/generic/threadshare/src/runtime/executor/timer.rs b/generic/threadshare/src/runtime/executor/timer.rs
index e08ebf39d..079c7a9ef 100644
--- a/generic/threadshare/src/runtime/executor/timer.rs
+++ b/generic/threadshare/src/runtime/executor/timer.rs
@@ -83,6 +83,16 @@ impl Timer {
         Timer::interval_at(Instant::now() + period, period)
     }
 
+    /// Creates a timer that emits events periodically, starting after `delay`.
+    ///
+    /// When throttling is activated (i.e. when using a non-`0` `wait`
+    /// duration in `Context::acquire`), timer entries are assigned to
+    /// the nearest time frame, meaning that the delay might elapse
+    /// `wait` / 2 ms earlier or later than the expected instant.
+    pub fn interval_delayed_by(delay: Duration, period: Duration) -> Timer {
+        Timer::interval_at(Instant::now() + delay, period)
+    }
+
     /// Creates a timer that emits events periodically, starting at `start`.
     ///
     /// When throttling is activated (i.e. when using a non-`0` `wait`