From 084a14b114a2a75cc125bf301d38af0843f42ae2 Mon Sep 17 00:00:00 2001
From: Norman Feske <norman.feske@genode-labs.com>
Date: Fri, 19 Apr 2024 11:30:44 +0200
Subject: [PATCH] record_play_mixer: make warning rate configurable

This patch disables latency warnings by default. The warnings can be
enabled by setting the 'warning_rate_ms` value to the desired
maximum rate.

Fixes #5186
Issue #5174
---
 repos/gems/sculpt/launcher/mixer              |  2 +-
 repos/os/src/server/record_play_mixer/README  | 11 +++++++++++
 repos/os/src/server/record_play_mixer/main.cc |  8 +++++++-
 3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/repos/gems/sculpt/launcher/mixer b/repos/gems/sculpt/launcher/mixer
index 94c2bb0694..4e251be0f8 100644
--- a/repos/gems/sculpt/launcher/mixer
+++ b/repos/gems/sculpt/launcher/mixer
@@ -1,5 +1,5 @@
 <launcher pkg="record_play_mixer" priority="0">
-	<config jitter_ms="10">
+	<config jitter_ms="10" warning_rate_ms="0">
 		<!--
 			These default wildcard rules match all regular play clients.
 			Please check the mixer report to replace the fuzzy configuration
diff --git a/repos/os/src/server/record_play_mixer/README b/repos/os/src/server/record_play_mixer/README
index 9d10d0006e..b0189fade0 100644
--- a/repos/os/src/server/record_play_mixer/README
+++ b/repos/os/src/server/record_play_mixer/README
@@ -98,3 +98,14 @@ Example
 The _gems/run/waveform_player.run_ script illustrates the integration and
 configuration of the mixer by using a waveform generator as play client and an
 oscilloscope as record client.
+
+Diagnostic features
+~~~~~~~~~~~~~~~~~~~
+
+The time-stable processing of audio streams depends on system-global
+parameters such as the kernel scheduling and CPU affinities of the mixer,
+drivers, and applications.
+To assist with the integration of the mixer and with choosing sensible jitter
+and period parameters, the config attribute 'warning_rate_ms' can be set to a
+maximum rate at which timing violations are reported. The default value of "0"
+suppresses those warning messages.
diff --git a/repos/os/src/server/record_play_mixer/main.cc b/repos/os/src/server/record_play_mixer/main.cc
index 15fb4cb73a..3618a862c9 100644
--- a/repos/os/src/server/record_play_mixer/main.cc
+++ b/repos/os/src/server/record_play_mixer/main.cc
@@ -49,6 +49,8 @@ struct Mixer::Main : Record_session::Operations, Play_session::Operations
 	using Config_version = String<32>;
 	Config_version _version { };
 
+	unsigned _warning_rate_ms = 0;
+
 	Constructible<Clock> _clock_from_config { };
 
 	Time_window_scheduler::Config _global_record_config { };
@@ -151,6 +153,11 @@ struct Mixer::Main : Record_session::Operations, Play_session::Operations
 		_config.update();
 		Xml_node const config = _config.xml();
 
+		unsigned const orig_warning_rate_ms = _warning_rate_ms;
+		_warning_rate_ms = config.attribute_value("warning_rate_ms", 0u);
+		if (orig_warning_rate_ms != _warning_rate_ms)
+			_timer.trigger_periodic(_warning_rate_ms*1000);
+
 		double const default_jitter_ms = config.attribute_value("jitter_ms", 1.0);
 		_global_record_config = {
 			.period_us = us_from_ms_attr(config, "record_period_ms", 5.0),
@@ -223,7 +230,6 @@ struct Mixer::Main : Record_session::Operations, Play_session::Operations
 		_handle_config();
 
 		_timer.sigh(_timer_handler);
-		_timer.trigger_periodic(1000*1000);
 
 		_env.parent().announce(_env.ep().manage(_play_root));
 		_env.parent().announce(_env.ep().manage(_record_root));