Renderer: Implement new render scheduling (#10936)

Implements a new render scheduling method, where we triple buffer when necessary.

Enabled by default, improves FPS on underpowered devices.

---------

Co-authored-by: Mihai Fufezan <mihai@fufexan.net>

src/helpers/DamageRing.hpp

@@ -3,7 +3,7 @@
 #include "./math/Math.hpp"
 #include <array>
 
-constexpr static int DAMAGE_RING_PREVIOUS_LEN = 2;
+constexpr static int DAMAGE_RING_PREVIOUS_LEN = 3;
 
 class CDamageRing {
   public:

src/helpers/Monitor.cpp

@@ -29,6 +29,7 @@
 #include <aquamarine/output/Output.hpp>
 #include "debug/Log.hpp"
 #include "debug/HyprNotificationOverlay.hpp"
+#include "MonitorFrameScheduler.hpp"
 #include <hyprutils/string/String.hpp>
 #include <hyprutils/utils/ScopeGuard.hpp>
 #include <cstring>
@@ -67,7 +68,7 @@ void CMonitor::onConnect(bool noRule) {
 
     g_pEventLoopManager->doLater([] { g_pConfigManager->ensurePersistentWorkspacesPresent(); });
 
-    m_listeners.frame  = m_output->events.frame.registerListener([this](std::any d) { onMonitorFrame(); });
+    m_listeners.frame  = m_output->events.frame.registerListener([this](std::any d) { m_frameScheduler->onFrame(); });
     m_listeners.commit = m_output->events.commit.registerListener([this](std::any d) {
         if (true) { // FIXME: E->state->committed & WLR_OUTPUT_STATE_BUFFER
             PROTO::screencopy->onOutputCommit(m_self.lock());
@@ -92,6 +93,8 @@ void CMonitor::onConnect(bool noRule) {
             PROTO::presentation->onPresented(m_self.lock(), Time::steadyNow(), E.refresh, E.seq, E.flags);
         else
             PROTO::presentation->onPresented(m_self.lock(), Time::fromTimespec(E.when), E.refresh, E.seq, E.flags);
+
+        m_frameScheduler->onPresented();
     });
 
     m_listeners.destroy = m_output->events.destroy.registerListener([this](std::any d) {
@@ -134,6 +137,8 @@ void CMonitor::onConnect(bool noRule) {
         applyMonitorRule(&rule);
     });
 
+    m_frameScheduler = makeUnique<CMonitorFrameScheduler>(m_self.lock());
+
     m_tearingState.canTear = m_output->getBackend()->type() == Aquamarine::AQ_BACKEND_DRM;
 
     m_name = m_output->name;
@@ -306,6 +311,8 @@ void CMonitor::onDisconnect(bool destroy) {
         m_renderTimer = nullptr;
     }
 
+    m_frameScheduler.reset();
+
     if (!m_enabled || g_pCompositor->m_isShuttingDown)
         return;
 
@@ -1562,69 +1569,6 @@ void CMonitor::debugLastPresentation(const std::string& message) {
                m_lastPresentationTimer.getMillis() > 0 ? 1000.0f / m_lastPresentationTimer.getMillis() : 0.0f);
 }
 
-void CMonitor::onMonitorFrame() {
-    if ((g_pCompositor->m_aqBackend->hasSession() && !g_pCompositor->m_aqBackend->session->active) || !g_pCompositor->m_sessionActive || g_pCompositor->m_unsafeState) {
-        Debug::log(WARN, "Attempted to render frame on inactive session!");
-
-        if (g_pCompositor->m_unsafeState && std::ranges::any_of(g_pCompositor->m_monitors.begin(), g_pCompositor->m_monitors.end(), [&](auto& m) {
-                return m->m_output != g_pCompositor->m_unsafeOutput->m_output;
-            })) {
-            // restore from unsafe state
-            g_pCompositor->leaveUnsafeState();
-        }
-
-        return; // cannot draw on session inactive (different tty)
-    }
-
-    if (!m_enabled)
-        return;
-
-    g_pHyprRenderer->recheckSolitaryForMonitor(m_self.lock());
-
-    m_tearingState.busy = false;
-
-    if (m_tearingState.activelyTearing && m_solitaryClient.lock() /* can be invalidated by a recheck */) {
-
-        if (!m_tearingState.frameScheduledWhileBusy)
-            return; // we did not schedule a frame yet to be displayed, but we are tearing. Why render?
-
-        m_tearingState.nextRenderTorn          = true;
-        m_tearingState.frameScheduledWhileBusy = false;
-    }
-
-    static auto PENABLERAT = CConfigValue<Hyprlang::INT>("misc:render_ahead_of_time");
-    static auto PRATSAFE   = CConfigValue<Hyprlang::INT>("misc:render_ahead_safezone");
-
-    m_lastPresentationTimer.reset();
-
-    if (*PENABLERAT && !m_tearingState.nextRenderTorn) {
-        if (!m_ratsScheduled) {
-            // render
-            g_pHyprRenderer->renderMonitor(m_self.lock());
-        }
-
-        m_ratsScheduled = false;
-
-        const auto& [avg, max, min] = g_pHyprRenderer->getRenderTimes(m_self.lock());
-
-        if (max + *PRATSAFE > 1000.0 / m_refreshRate)
-            return;
-
-        const auto MSLEFT = (1000.0 / m_refreshRate) - m_lastPresentationTimer.getMillis();
-
-        m_ratsScheduled = true;
-
-        const auto ESTRENDERTIME = std::ceil(avg + *PRATSAFE);
-        const auto TIMETOSLEEP   = std::floor(MSLEFT - ESTRENDERTIME);
-
-        if (MSLEFT < 1 || MSLEFT < ESTRENDERTIME || TIMETOSLEEP < 1)
-            g_pHyprRenderer->renderMonitor(m_self.lock());
-        else
-            wl_event_source_timer_update(m_renderTimer, TIMETOSLEEP);
-    } else
-        g_pHyprRenderer->renderMonitor(m_self.lock());
-}
-
 void CMonitor::onCursorMovedOnMonitor() {
     if (!m_tearingState.activelyTearing || !m_solitaryClient || !g_pHyprRenderer->shouldRenderCursor())
         return;
@@ -1717,7 +1661,7 @@ bool CMonitorState::updateSwapchain() {
     }
     options.format  = m_owner->m_drmFormat;
     options.scanout = true;
-    options.length  = 2;
+    options.length  = 3;
     options.size    = MODE->pixelSize;
     return m_owner->m_output->swapchain->reconfigure(options);
 }

src/helpers/Monitor.hpp

@@ -20,6 +20,8 @@
 #include <aquamarine/allocator/Swapchain.hpp>
 #include <hyprutils/os/FileDescriptor.hpp>
 
+class CMonitorFrameScheduler;
+
 // Enum for the different types of auto directions, e.g. auto-left, auto-up.
 enum eAutoDirs : uint8_t {
     DIR_AUTO_NONE = 0, /* None will be treated as right. */
@@ -160,6 +162,8 @@ class CMonitor {
 
     PHLMONITORREF                  m_self;
 
+    UP<CMonitorFrameScheduler>     m_frameScheduler;
+
     // mirroring
     PHLMONITORREF              m_mirrorOf;
     std::vector<PHLMONITORREF> m_mirrors;
@@ -228,7 +232,6 @@ class CMonitor {
     void                                onCursorMovedOnMonitor();
 
     void                                debugLastPresentation(const std::string& message);
-    void                                onMonitorFrame();
 
     bool                                supportsWideColor();
     bool                                supportsHDR();

src/helpers/MonitorFrameScheduler.cpp

@@ -0,0 +1,130 @@
+#include "MonitorFrameScheduler.hpp"
+#include "../config/ConfigValue.hpp"
+#include "../Compositor.hpp"
+#include "../render/Renderer.hpp"
+#include "../managers/eventLoop/EventLoopManager.hpp"
+
+CMonitorFrameScheduler::CMonitorFrameScheduler(PHLMONITOR m) : m_monitor(m) {
+    ;
+}
+
+void CMonitorFrameScheduler::onSyncFired() {
+    static auto PENABLENEW = CConfigValue<Hyprlang::INT>("render:new_render_scheduling");
+
+    if (!*PENABLENEW)
+        return;
+
+    // Sync fired: reset submitted state, set as rendered. Check the last render time. If we are running
+    // late, we will instantly render here.
+
+    if (std::chrono::duration_cast<std::chrono::microseconds>(hrc::now() - m_lastRenderBegun).count() / 1000.F < 1000.F / m_monitor->m_refreshRate) {
+        // we are in. Frame is valid. We can just render as normal.
+        Debug::log(TRACE, "CMonitorFrameScheduler: {} -> onSyncFired, didn't miss.", m_monitor->m_name);
+        m_renderAtFrame = true;
+        return;
+    }
+
+    Debug::log(TRACE, "CMonitorFrameScheduler: {} -> onSyncFired, missed.", m_monitor->m_name);
+
+    // we are out. The frame is taking too long to render. Begin rendering immediately, but don't commit yet.
+    m_pendingThird  = true;
+    m_renderAtFrame = false; // block frame rendering, we already scheduled
+
+    m_lastRenderBegun = hrc::now();
+    g_pHyprRenderer->renderMonitor(m_monitor.lock(), false);
+    onFinishRender();
+}
+
+void CMonitorFrameScheduler::onPresented() {
+    static auto PENABLENEW = CConfigValue<Hyprlang::INT>("render:new_render_scheduling");
+
+    if (!*PENABLENEW)
+        return;
+
+    if (!m_pendingThird)
+        return;
+
+    Debug::log(TRACE, "CMonitorFrameScheduler: {} -> onPresented, missed, committing pending.", m_monitor->m_name);
+
+    m_pendingThird = false;
+
+    Debug::log(TRACE, "CMonitorFrameScheduler: {} -> onPresented, missed, committing pending at the earliest convenience.", m_monitor->m_name);
+
+    m_pendingThird = false;
+
+    g_pEventLoopManager->doLater([m = m_monitor.lock()] {
+        g_pHyprRenderer->commitPendingAndDoExplicitSync(m); // commit the pending frame. If it didn't fire yet (is not rendered) it doesn't matter. Syncs will wait.
+
+        // schedule a frame: we might have some missed damage, which got cleared due to the above commit.
+        // TODO: this is not always necessary, but doesn't hurt in general. We likely won't hit this if nothing's happening anyways.
+        if (m->m_damage.hasChanged())
+            g_pCompositor->scheduleFrameForMonitor(m);
+    });
+}
+
+void CMonitorFrameScheduler::onFrame() {
+    static auto PENABLENEW = CConfigValue<Hyprlang::INT>("render:new_render_scheduling");
+
+    if (!canRender())
+        return;
+
+    g_pHyprRenderer->recheckSolitaryForMonitor(m_monitor.lock());
+
+    m_monitor->m_tearingState.busy = false;
+
+    if (m_monitor->m_tearingState.activelyTearing && m_monitor->m_solitaryClient.lock() /* can be invalidated by a recheck */) {
+
+        if (!m_monitor->m_tearingState.frameScheduledWhileBusy)
+            return; // we did not schedule a frame yet to be displayed, but we are tearing. Why render?
+
+        m_monitor->m_tearingState.nextRenderTorn          = true;
+        m_monitor->m_tearingState.frameScheduledWhileBusy = false;
+    }
+
+    if (!*PENABLENEW) {
+        m_monitor->m_lastPresentationTimer.reset();
+
+        g_pHyprRenderer->renderMonitor(m_monitor.lock());
+        return;
+    }
+
+    if (!m_renderAtFrame) {
+        Debug::log(TRACE, "CMonitorFrameScheduler: {} -> frame event, but m_renderAtFrame = false.", m_monitor->m_name);
+        return;
+    }
+
+    Debug::log(TRACE, "CMonitorFrameScheduler: {} -> frame event, render = true, rendering normally.", m_monitor->m_name);
+
+    m_lastRenderBegun = hrc::now();
+    g_pHyprRenderer->renderMonitor(m_monitor.lock());
+    onFinishRender();
+}
+
+void CMonitorFrameScheduler::onFinishRender() {
+    m_sync = CEGLSync::create(); // this destroys the old sync
+    g_pEventLoopManager->doOnReadable(m_sync->fd().duplicate(), [this, mon = m_monitor] {
+        if (!m_monitor) // might've gotten destroyed
+            return;
+        onSyncFired();
+    });
+}
+
+bool CMonitorFrameScheduler::canRender() {
+    if ((g_pCompositor->m_aqBackend->hasSession() && !g_pCompositor->m_aqBackend->session->active) || !g_pCompositor->m_sessionActive || g_pCompositor->m_unsafeState) {
+        Debug::log(WARN, "Attempted to render frame on inactive session!");
+
+        if (g_pCompositor->m_unsafeState && std::ranges::any_of(g_pCompositor->m_monitors.begin(), g_pCompositor->m_monitors.end(), [&](auto& m) {
+                return m->m_output != g_pCompositor->m_unsafeOutput->m_output;
+            })) {
+            // restore from unsafe state
+            g_pCompositor->leaveUnsafeState();
+        }
+
+        return false; // cannot draw on session inactive (different tty)
+    }
+
+    if (!m_monitor->m_enabled)
+        return false;
+
+    return true;
+}

src/helpers/MonitorFrameScheduler.hpp

@@ -0,0 +1,35 @@
+#pragma once
+
+#include "Monitor.hpp"
+
+#include <chrono>
+
+class CEGLSync;
+
+class CMonitorFrameScheduler {
+  public:
+    using hrc = std::chrono::high_resolution_clock;
+
+    CMonitorFrameScheduler(PHLMONITOR m);
+
+    CMonitorFrameScheduler(const CMonitorFrameScheduler&)            = delete;
+    CMonitorFrameScheduler(CMonitorFrameScheduler&&)                 = delete;
+    CMonitorFrameScheduler& operator=(const CMonitorFrameScheduler&) = delete;
+    CMonitorFrameScheduler& operator=(CMonitorFrameScheduler&&)      = delete;
+
+    void                    onSyncFired();
+    void                    onPresented();
+    void                    onFrame();
+
+  private:
+    bool            canRender();
+    void            onFinishRender();
+
+    bool            m_renderAtFrame = true;
+    bool            m_pendingThird  = false;
+    hrc::time_point m_lastRenderBegun;
+
+    PHLMONITORREF   m_monitor;
+
+    UP<CEGLSync>    m_sync;
+};