Implement Lv2 Worker (#6484)

include/AudioEngine.h

@@ -197,6 +197,7 @@ public:
 
 	// audio-device-stuff
 
+	bool renderOnly() const { return m_renderOnly; }
 	// Returns the current audio device's name. This is not necessarily
 	// the user's preferred audio device, in case you were thinking that.
 	inline const QString & audioDevName() const

include/LmmsSemaphore.h

@@ -0,0 +1,93 @@
+/*
+ * Semaphore.h - Semaphore declaration
+ *
+ * Copyright (c) 2022-2022 Johannes Lorenz <jlsf2013$users.sourceforge.net, $=@>
+ *
+ * This file is part of LMMS - https://lmms.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+/*
+ * This code has been copied and adapted from https://github.com/drobilla/jalv
+ * File src/zix/sem.h
+ */
+
+#ifndef LMMS_SEMAPHORE_H
+#define LMMS_SEMAPHORE_H
+
+#include "lmmsconfig.h"
+
+#ifdef LMMS_BUILD_APPLE
+#    include <mach/mach.h>
+#elif defined(LMMS_BUILD_WIN32)
+#    include <windows.h>
+#else
+#    include <semaphore.h>
+#endif
+
+#include <system_error>
+
+namespace lmms {
+
+/**
+   A counting semaphore.
+
+   This is an integer that is always positive, and has two main operations:
+   increment (post) and decrement (wait).  If a decrement can not be performed
+   (i.e. the value is 0) the caller will be blocked until another thread posts
+   and the operation can succeed.
+
+   Semaphores can be created with any starting value, but typically this will
+   be 0 so the semaphore can be used as a simple signal where each post
+   corresponds to one wait.
+
+   Semaphores are very efficient (much moreso than a mutex/cond pair).  In
+   particular, at least on Linux, post is async-signal-safe, which means it
+   does not block and will not be interrupted.  If you need to signal from
+   a realtime thread, this is the most appropriate primitive to use.
+
+   @note Likely outdated with C++20's std::counting_semaphore
+		 (though we have to check that this will be RT conforming on all platforms)
+*/
+class Semaphore
+{
+public:
+	Semaphore(unsigned initial);
+	Semaphore(const Semaphore&) = delete;
+	Semaphore& operator=(const Semaphore&) = delete;
+	Semaphore(Semaphore&&) = delete;
+	Semaphore& operator=(Semaphore&&) = delete;
+	~Semaphore();
+
+	void post();
+	void wait();
+	bool tryWait();
+
+private:
+#ifdef LMMS_BUILD_APPLE
+	semaphore_t m_sem;
+#elif defined(LMMS_BUILD_WIN32)
+	HANDLE m_sem;
+#else
+	sem_t m_sem;
+#endif
+};
+
+} // namespace lmms
+
+#endif // LMMS_SEMAPHORE_H

include/LocklessRingBuffer.h

@@ -51,13 +51,14 @@ public:
 	std::size_t capacity() const {return m_buffer.maximum_eventual_write_space();}
 	std::size_t free() const {return m_buffer.write_space();}
 	void wakeAll() {m_notifier.wakeAll();}
-	std::size_t write(const sampleFrame *src, std::size_t cnt, bool notify = false)
+	std::size_t write(const T *src, std::size_t cnt, bool notify = false)
 	{
 		std::size_t written = LocklessRingBuffer<T>::m_buffer.write(src, cnt);
 		// Let all waiting readers know new data are available.
 		if (notify) {LocklessRingBuffer<T>::m_notifier.wakeAll();}
 		return written;
 	}
+	void mlock() { m_buffer.mlock(); }
 
 protected:
 	ringbuffer_t<T> m_buffer;

include/Lv2Proc.h

@@ -1,7 +1,7 @@
 /*
  * Lv2Proc.h - Lv2 processor class
  *
- * Copyright (c) 2019-2020 Johannes Lorenz <jlsf2013$users.sourceforge.net, $=@>
+ * Copyright (c) 2019-2022 Johannes Lorenz <jlsf2013$users.sourceforge.net, $=@>
  *
  * This file is part of LMMS - https://lmms.io
  *
@@ -31,11 +31,14 @@
 
 #include <lilv/lilv.h>
 #include <memory>
+#include <optional>
 
+#include "LinkedModelGroups.h"
+#include "LmmsSemaphore.h"
 #include "Lv2Basics.h"
 #include "Lv2Features.h"
 #include "Lv2Options.h"
-#include "LinkedModelGroups.h"
+#include "Lv2Worker.h"
 #include "Plugin.h"
 #include "../src/3rdparty/ringbuffer/include/ringbuffer/ringbuffer.h"
 #include "TimePos.h"
@@ -174,8 +177,14 @@ private:
 	const LilvPlugin* m_plugin;
 	LilvInstance* m_instance;
 	Lv2Features m_features;
+
+	// options
 	Lv2Options m_options;
 
+	// worker
+	std::optional<Lv2Worker> m_worker;
+	Semaphore m_workLock; // this must be shared by different workers
+
 	// full list of ports
 	std::vector<std::unique_ptr<Lv2Ports::PortBase>> m_ports;
 	// quick reference to specific, unique ports

include/Lv2Worker.h

@@ -0,0 +1,93 @@
+/*
+ * Lv2Worker.h - Lv2Worker class
+ *
+ * Copyright (c) 2022-2022 Johannes Lorenz <jlsf2013$users.sourceforge.net, $=@>
+ *
+ * This file is part of LMMS - https://lmms.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+#ifndef LV2WORKER_H
+#define LV2WORKER_H
+
+#include "lmmsconfig.h"
+
+#ifdef LMMS_HAVE_LV2
+
+#include <lilv/lilv.h>
+#include <lv2/lv2plug.in/ns/ext/worker/worker.h>
+#include <thread>
+#include <vector>
+
+#include "LocklessRingBuffer.h"
+#include "LmmsSemaphore.h"
+
+namespace lmms
+{
+
+/**
+	Worker container
+*/
+class Lv2Worker
+{
+public:
+	// CTOR/DTOR/feature access
+	Lv2Worker(const LV2_Worker_Interface* iface, Semaphore* common_work_lock, bool threaded);
+	~Lv2Worker();
+	void setHandle(LV2_Handle handle) { m_handle = handle; }
+	LV2_Worker_Schedule* feature() { return &m_scheduleFeature; }
+
+	// public API
+	void emitResponses();
+	void notifyPluginThatRunFinished()
+	{
+		if(m_iface->end_run) { m_iface->end_run(m_scheduleFeature.handle); }
+	}
+
+	// to be called only by static functions
+	LV2_Worker_Status scheduleWork(uint32_t size, const void* data);
+	LV2_Worker_Status respond(uint32_t size, const void* data);
+
+private:
+	// functions
+	void workerFunc();
+	std::size_t bufferSize() const;  //!< size of internal buffers
+
+	// parameters
+	const LV2_Worker_Interface* m_iface;
+	bool m_threaded;
+	LV2_Handle m_handle;
+	LV2_Worker_Schedule m_scheduleFeature;
+
+	// threading/synchronization
+	std::thread m_thread;
+	std::vector<char> m_response;  //!< buffer where single requests from m_requests are unpacked
+	LocklessRingBuffer<char> m_requests, m_responses;  //!< ringbuffer to queue multiple requests
+	LocklessRingBufferReader<char> m_requestsReader, m_responsesReader;
+	std::atomic<bool> m_exit = false;  //!< Whether the worker function should keep looping
+	Semaphore m_sem;
+	Semaphore* m_workLock;
+};
+
+
+} // namespace lmms
+
+#endif // LMMS_HAVE_LV2
+
+#endif // LV2WORKER_H
+

src/core/CMakeLists.txt

@@ -70,6 +70,7 @@ set(LMMS_SRCS
 	core/SamplePlayHandle.cpp
 	core/SampleRecordHandle.cpp
 	core/Scale.cpp
+	core/LmmsSemaphore.cpp
 	core/SerializingObject.cpp
 	core/Song.cpp
 	core/TempoSyncKnobModel.cpp
@@ -112,6 +113,7 @@ set(LMMS_SRCS
 	core/lv2/Lv2SubPluginFeatures.cpp
 	core/lv2/Lv2UridCache.cpp
 	core/lv2/Lv2UridMap.cpp
+	core/lv2/Lv2Worker.cpp
 
 	core/midi/MidiAlsaRaw.cpp
 	core/midi/MidiAlsaSeq.cpp

src/core/LmmsSemaphore.cpp

@@ -0,0 +1,143 @@
+/*
+ * Semaphore.cpp - Semaphore implementation
+ *
+ * Copyright (c) 2022-2022 Johannes Lorenz <jlsf2013$users.sourceforge.net, $=@>
+ *
+ * This file is part of LMMS - https://lmms.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+/*
+ * This code has been copied and adapted from https://github.com/drobilla/jalv
+ * File src/zix/sem.h
+ */
+
+#include "LmmsSemaphore.h"
+
+#if defined(LMMS_BUILD_WIN32)
+#    include <limits.h>
+#else
+#    include <errno.h>
+#endif
+
+#include <system_error>
+
+namespace lmms {
+
+#ifdef LMMS_BUILD_APPLE
+Semaphore::Semaphore(unsigned val)
+{
+	kern_return_t rval = semaphore_create(mach_task_self(), &m_sem, SYNC_POLICY_FIFO, val);
+	if(rval != 0) {
+		throw std::system_error(rval, std::system_category(), "Could not create semaphore");
+	}
+}
+
+Semaphore::~Semaphore()
+{
+	semaphore_destroy(mach_task_self(), m_sem);
+}
+
+void Semaphore::post()
+{
+	semaphore_signal(m_sem);
+}
+
+void Semaphore::wait()
+{
+	kern_return_t rval = semaphore_wait(m_sem);
+	if (rval != KERN_SUCCESS) {
+		throw std::system_error(rval, std::system_category(), "Waiting for semaphore failed");
+	}
+}
+
+bool Semaphore::tryWait()
+{
+	const mach_timespec_t zero = { 0, 0 };
+	return semaphore_timedwait(m_sem, zero) == KERN_SUCCESS;
+}
+
+#elif defined(LMMS_BUILD_WIN32)
+
+Semaphore::Semaphore(unsigned initial)
+{
+	if(CreateSemaphore(nullptr, initial, LONG_MAX, nullptr) == nullptr) {
+		throw std::system_error(GetLastError(), std::system_category(), "Could not create semaphore");
+	}
+}
+
+Semaphore::~Semaphore()
+{
+	CloseHandle(m_sem);
+}
+
+void Semaphore::post()
+{
+	ReleaseSemaphore(m_sem, 1, nullptr);
+}
+
+void Semaphore::wait()
+{
+	if (WaitForSingleObject(m_sem, INFINITE) != WAIT_OBJECT_0) {
+		throw std::system_error(GetLastError(), std::system_category(), "Waiting for semaphore failed");
+	}
+}
+
+bool Semaphore::tryWait()
+{
+	return WaitForSingleObject(m_sem, 0) == WAIT_OBJECT_0;
+}
+
+#else  /* !defined(LMMS_BUILD_APPLE) && !defined(LMMS_BUILD_WIN32) */
+
+Semaphore::Semaphore(unsigned initial)
+{
+	if(sem_init(&m_sem, 0, initial) != 0) {
+		throw std::system_error(errno, std::generic_category(), "Could not create semaphore");
+	}
+}
+
+Semaphore::~Semaphore()
+{
+	sem_destroy(&m_sem);
+}
+
+void Semaphore::post()
+{
+	sem_post(&m_sem);
+}
+
+void Semaphore::wait()
+{
+	while (sem_wait(&m_sem) != 0) {
+		if (errno != EINTR) {
+			throw std::system_error(errno, std::generic_category(), "Waiting for semaphore failed");
+		}
+		/* Otherwise, interrupted, so try again. */
+	}
+}
+
+bool Semaphore::tryWait()
+{
+	return (sem_trywait(&m_sem) == 0);
+}
+
+#endif
+
+} // namespace lmms
+

src/core/lv2/Lv2Manager.cpp

@@ -31,6 +31,7 @@
 #include <lilv/lilv.h>
 #include <lv2/lv2plug.in/ns/ext/buf-size/buf-size.h>
 #include <lv2/lv2plug.in/ns/ext/options/options.h>
+#include <lv2/lv2plug.in/ns/ext/worker/worker.h>
 #include <QDebug>
 #include <QElapsedTimer>
 
@@ -172,6 +173,7 @@ Lv2Manager::Lv2Manager() :
 	m_supportedFeatureURIs.insert(LV2_URID__map);
 	m_supportedFeatureURIs.insert(LV2_URID__unmap);
 	m_supportedFeatureURIs.insert(LV2_OPTIONS__options);
+	m_supportedFeatureURIs.insert(LV2_WORKER__schedule);
 	// min/max is always passed in the options
 	m_supportedFeatureURIs.insert(LV2_BUF_SIZE__boundedBlockLength);
 	// block length is only changed initially in AudioEngine CTOR

src/core/lv2/Lv2Proc.cpp

@@ -1,7 +1,7 @@
 /*
  * Lv2Proc.cpp - Lv2 processor class
  *
- * Copyright (c) 2019-2020 Johannes Lorenz <jlsf2013$users.sourceforge.net, $=@>
+ * Copyright (c) 2019-2022 Johannes Lorenz <jlsf2013$users.sourceforge.net, $=@>
  *
  * This file is part of LMMS - https://lmms.io
  *
@@ -30,6 +30,7 @@
 #include <lv2/lv2plug.in/ns/ext/midi/midi.h>
 #include <lv2/lv2plug.in/ns/ext/atom/atom.h>
 #include <lv2/lv2plug.in/ns/ext/resize-port/resize-port.h>
+#include <lv2/lv2plug.in/ns/ext/worker/worker.h>
 #include <QDebug>
 #include <QDomDocument>
 #include <QtGlobal>
@@ -170,6 +171,7 @@ Plugin::Type Lv2Proc::check(const LilvPlugin *plugin,
 Lv2Proc::Lv2Proc(const LilvPlugin *plugin, Model* parent) :
 	LinkedModelGroup(parent),
 	m_plugin(plugin),
+	m_workLock(1),
 	m_midiInputBuf(m_maxMidiInputEvents),
 	m_midiInputReader(m_midiInputBuf)
 {
@@ -360,7 +362,19 @@ void Lv2Proc::copyBuffersToCore(sampleFrame* buf,
 
 void Lv2Proc::run(fpp_t frames)
 {
+	if (m_worker)
+	{
+		// Process any worker replies
+		m_worker->emitResponses();
+	}
+
 	lilv_instance_run(m_instance, static_cast<uint32_t>(frames));
+
+	if (m_worker)
+	{
+		// Notify the plugin the run() cycle is finished
+		m_worker->notifyPluginThatRunFinished();
+	}
 }
 
 
@@ -428,6 +442,9 @@ void Lv2Proc::initPlugin()
 
 	if (m_instance)
 	{
+		if(m_worker) {
+			m_worker->setHandle(lilv_instance_get_handle(m_instance));
+		}
 		for (std::size_t portNum = 0; portNum < m_ports.size(); ++portNum)
 			connectPort(portNum);
 		lilv_instance_activate(m_instance);
@@ -504,8 +521,20 @@ void Lv2Proc::initMOptions()
 
 void Lv2Proc::initPluginSpecificFeatures()
 {
+	// options
 	initMOptions();
 	m_features[LV2_OPTIONS__options] = const_cast<LV2_Options_Option*>(m_options.feature());
+
+	// worker (if plugin has worker extension)
+	Lv2Manager* mgr = Engine::getLv2Manager();
+	if (lilv_plugin_has_extension_data(m_plugin, mgr->uri(LV2_WORKER__interface).get())) {
+		const auto iface = static_cast<const LV2_Worker_Interface*>(
+			lilv_instance_get_extension_data(m_instance, LV2_WORKER__interface));
+		bool threaded = !Engine::audioEngine()->renderOnly();
+		m_worker.emplace(iface, &m_workLock, threaded);
+		m_features[LV2_WORKER__schedule] = m_worker->feature();
+		// Note: m_worker::setHandle will still need to be called later
+	}
 }
 
 

src/core/lv2/Lv2Worker.cpp

@@ -0,0 +1,203 @@
+/*
+ * Lv2Worker.cpp - Lv2Worker implementation
+ *
+ * Copyright (c) 2022-2022 Johannes Lorenz <jlsf2013$users.sourceforge.net, $=@>
+ *
+ * This file is part of LMMS - https://lmms.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include "Lv2Worker.h"
+
+#include <cassert>
+#include <QDebug>
+
+#ifdef LMMS_HAVE_LV2
+
+#include "Engine.h"
+
+
+namespace lmms
+{
+
+
+// static wrappers
+
+static LV2_Worker_Status
+staticWorkerRespond(LV2_Worker_Respond_Handle handle,
+	uint32_t size, const void* data)
+{
+	Lv2Worker* worker = static_cast<Lv2Worker*>(handle);
+	return worker->respond(size, data);
+}
+
+
+
+
+std::size_t Lv2Worker::bufferSize() const
+{
+	// ardour uses this fixed size for ALSA:
+	return 8192 * 4;
+	// for jack, they use 4 * jack_port_type_get_buffer_size (..., JACK_DEFAULT_MIDI_TYPE)
+	// (possible extension for AudioDevice)
+}
+
+
+
+
+Lv2Worker::Lv2Worker(const LV2_Worker_Interface* iface,
+	Semaphore* common_work_lock,
+	bool threaded) :
+	m_iface(iface),
+	m_threaded(threaded),
+	m_response(bufferSize()),
+	m_requests(bufferSize()),
+	m_responses(bufferSize()),
+	m_requestsReader(m_requests),
+	m_responsesReader(m_responses),
+	m_sem(0),
+	m_workLock(common_work_lock)
+{
+	assert(iface);
+	m_scheduleFeature.handle = static_cast<LV2_Worker_Schedule_Handle>(this);
+	m_scheduleFeature.schedule_work = [](LV2_Worker_Schedule_Handle handle,
+		uint32_t size, const void* data) -> LV2_Worker_Status
+		{
+			Lv2Worker* worker = static_cast<Lv2Worker*>(handle);
+			return worker->scheduleWork(size, data);
+		};
+
+	if (threaded) { m_thread = std::thread(&Lv2Worker::workerFunc, this); }
+
+	m_requests.mlock();
+	m_responses.mlock();
+}
+
+
+
+
+Lv2Worker::~Lv2Worker()
+{
+	m_exit = true;
+	if(m_threaded) {
+		m_sem.post();
+		m_thread.join();
+	}
+}
+
+
+
+
+// Let the worker send responses to the audio thread
+LV2_Worker_Status Lv2Worker::respond(uint32_t size, const void* data)
+{
+	if(m_threaded)
+	{
+		if(m_responses.free() < sizeof(size) + size)
+		{
+			return LV2_WORKER_ERR_NO_SPACE;
+		}
+		else
+		{
+			m_responses.write((const char*)&size, sizeof(size));
+			if(size && data) { m_responses.write((const char*)data, size); }
+		}
+	}
+	else
+	{
+		m_iface->work_response(m_handle, size, data);
+	}
+	return LV2_WORKER_SUCCESS;
+}
+
+
+
+
+// Let the worker receive work from the audio thread and "work" on it
+void Lv2Worker::workerFunc()
+{
+	std::vector<char> buf;
+	uint32_t size;
+	while (true) {
+		m_sem.wait();
+		if (m_exit) { break; }
+		const std::size_t readSpace = m_requestsReader.read_space();
+		if (readSpace <= sizeof(size)) { continue; } // (should not happen)
+
+		m_requestsReader.read(sizeof(size)).copy((char*)&size, sizeof(size));
+		assert(size <= readSpace - sizeof(size));
+		if(size > buf.size()) { buf.resize(size); }
+		if(size) { m_requestsReader.read(size).copy(buf.data(), size); }
+
+		m_workLock->wait();
+		m_iface->work(m_handle, staticWorkerRespond, this, size, buf.data());
+		m_workLock->post();
+	}
+}
+
+
+
+
+// Let the audio thread schedule work for the worker
+LV2_Worker_Status Lv2Worker::scheduleWork(uint32_t size, const void *data)
+{
+	if (m_threaded)
+	{
+		if(m_requests.free() < sizeof(size) + size)
+		{
+			return LV2_WORKER_ERR_NO_SPACE;
+		}
+		else
+		{
+			// Schedule a request to be executed by the worker thread
+			m_requests.write((const char*)&size, sizeof(size));
+			if(size && data) { m_requests.write((const char*)data, size); }
+			m_sem.post();
+		}
+	}
+	else
+	{
+		// Execute work immediately in this thread
+		m_workLock->wait();
+		m_iface->work(m_handle, staticWorkerRespond, this, size, data);
+		m_workLock->post();
+	}
+
+	return LV2_WORKER_SUCCESS;
+}
+
+
+
+
+// Let the audio thread read incoming worker responses, and process it
+void Lv2Worker::emitResponses()
+{
+	std::size_t read_space = m_responsesReader.read_space();
+	uint32_t size;
+	while (read_space > sizeof(size)) {
+		m_responsesReader.read(sizeof(size)).copy((char*)&size, sizeof(size));
+		if(size) { m_responsesReader.read(size).copy(m_response.data(), size); }
+		m_iface->work_response(m_handle, size, m_response.data());
+		read_space -= sizeof(size) + size;
+	}
+}
+
+
+} // namespace lmms
+
+#endif // LMMS_HAVE_LV2