Add benchmark

lib/I18n/translations/english.yaml

@@ -389,6 +389,7 @@ STR_DELETE_CONFIRM: "Delete this server?"
 STR_OPDS_SERVERS: "OPDS Servers"
 STR_AUTO_TURN_ENABLED: "Auto Turn Enabled: "
 STR_AUTO_TURN_PAGES_PER_MIN: "Auto Turn (Pages Per Minute)"
+STR_RENDER_BENCHMARK: "Render Benchmark"
 STR_WEATHER: "Weather"
 STR_WEATHER_LOCATION: "Location"
 STR_WEATHER_UNITS: "Units"

src/activities/reader/EpubReaderActivity.cpp

@@ -7,6 +7,7 @@
 #include <Epub/Page.h>
 #include <Epub/blocks/TextBlock.h>
 #include <FontCacheManager.h>
+#include <FontDecompressor.h>
 #include <FsHelpers.h>
 #include <GfxRenderer.h>
 #include <HalStorage.h>
@@ -22,6 +23,7 @@
 #include "EpubReaderChapterSelectionActivity.h"
 #include "EpubReaderFootnotesActivity.h"
 #include "EpubReaderPercentSelectionActivity.h"
+#include "EpubRenderBenchmarkActivity.h"
 #include "GlobalBookmarkIndex.h"
 #include "KOReaderCredentialStore.h"
 #include "MappedInputManager.h"
@@ -79,6 +81,20 @@ int clampPercent(int percent) {
   return percent;
 }
 
+const char* orientationToString(const GfxRenderer::Orientation orientation) {
+  switch (orientation) {
+    case GfxRenderer::Portrait:
+      return "Portrait";
+    case GfxRenderer::LandscapeClockwise:
+      return "Landscape CW";
+    case GfxRenderer::PortraitInverted:
+      return "Portrait Inverted";
+    case GfxRenderer::LandscapeCounterClockwise:
+      return "Landscape CCW";
+  }
+  return "Unknown";
+}
+
 }  // namespace
 
 void EpubReaderActivity::onEnter() {
@@ -593,6 +609,10 @@ void EpubReaderActivity::onReaderMenuConfirm(EpubReaderMenuActivity::MenuAction
       onGoHome();
       return;
     }
+    case EpubReaderMenuActivity::MenuAction::RENDER_BENCHMARK: {
+      runRenderBenchmark();
+      break;
+    }
     case EpubReaderMenuActivity::MenuAction::SCREENSHOT: {
       {
         RenderLock lock(*this);
@@ -620,6 +640,202 @@ void EpubReaderActivity::onReaderMenuConfirm(EpubReaderMenuActivity::MenuAction
   }
 }
 
+void EpubReaderActivity::runRenderBenchmark() {
+  if (!epub) {
+    return;
+  }
+
+  if (!section) {
+    requestUpdateAndWait();
+    if (!section) {
+      return;
+    }
+  }
+
+  const LastRenderStats startSnapshot = lastRenderStats;
+  BenchmarkAggregate aggregate;
+  auto recordRender = [&aggregate](const LastRenderStats& snapshot) {
+    if (!snapshot.valid) {
+      return;
+    }
+
+    aggregate.renderCount++;
+    aggregate.imagePageCount += snapshot.hadImages ? 1 : 0;
+    aggregate.cacheRebuildCount += snapshot.cacheRebuilt ? 1 : 0;
+    if (snapshot.footnoteCount > aggregate.maxFootnotes) {
+      aggregate.maxFootnotes = snapshot.footnoteCount;
+    }
+
+    aggregate.totalRequestRenderMs += snapshot.requestRenderMs;
+    if (aggregate.renderCount == 1 || snapshot.requestRenderMs < aggregate.minRequestRenderMs) {
+      aggregate.minRequestRenderMs = snapshot.requestRenderMs;
+    }
+    if (snapshot.requestRenderMs > aggregate.maxRequestRenderMs) {
+      aggregate.maxRequestRenderMs = snapshot.requestRenderMs;
+    }
+
+    aggregate.totalRenderMs += snapshot.phases.totalMs;
+    if (aggregate.renderCount == 1 || snapshot.phases.totalMs < aggregate.minRenderMs) {
+      aggregate.minRenderMs = snapshot.phases.totalMs;
+    }
+    if (snapshot.phases.totalMs > aggregate.maxRenderMs) {
+      aggregate.maxRenderMs = snapshot.phases.totalMs;
+    }
+
+    aggregate.totalSectionLoadMs += snapshot.sectionLoadMs;
+    aggregate.totalPageLoadMs += snapshot.pageLoadMs;
+    aggregate.totalPhases.prewarmMs += snapshot.phases.prewarmMs;
+    aggregate.totalPhases.bwRenderMs += snapshot.phases.bwRenderMs;
+    aggregate.totalPhases.displayMs += snapshot.phases.displayMs;
+    aggregate.totalPhases.bwStoreMs += snapshot.phases.bwStoreMs;
+    aggregate.totalPhases.grayLsbMs += snapshot.phases.grayLsbMs;
+    aggregate.totalPhases.grayMsbMs += snapshot.phases.grayMsbMs;
+    aggregate.totalPhases.grayDisplayMs += snapshot.phases.grayDisplayMs;
+    aggregate.totalPhases.bwRestoreMs += snapshot.phases.bwRestoreMs;
+    aggregate.totalPhases.totalMs += snapshot.phases.totalMs;
+
+    aggregate.totalFontCacheHits += snapshot.fontCacheHits;
+    aggregate.totalFontCacheMisses += snapshot.fontCacheMisses;
+    aggregate.totalFontDecompressMs += snapshot.fontDecompressMs;
+    aggregate.totalFontGetBitmapTimeUs += snapshot.fontGetBitmapTimeUs;
+    aggregate.totalFontGetBitmapCalls += snapshot.fontGetBitmapCalls;
+
+    if (aggregate.renderCount == 1 || snapshot.freeHeapAfter < aggregate.minFreeHeapAfter) {
+      aggregate.minFreeHeapAfter = snapshot.freeHeapAfter;
+    }
+    if (snapshot.freeHeapAfter > aggregate.maxFreeHeapAfter) {
+      aggregate.maxFreeHeapAfter = snapshot.freeHeapAfter;
+    }
+  };
+  const unsigned long startTime = millis();
+  int forwardTurns = 0;
+  int backwardTurns = 0;
+
+  for (int i = 0; i < 10; i++) {
+    if (!stepPageState(true)) {
+      break;
+    }
+    requestUpdateAndWait();
+    recordRender(lastRenderStats);
+    forwardTurns++;
+  }
+
+  const unsigned long forwardMs = millis() - startTime;
+  const unsigned long backwardStart = millis();
+
+  for (int i = 0; i < 10; i++) {
+    if (!stepPageState(false)) {
+      break;
+    }
+    requestUpdateAndWait();
+    recordRender(lastRenderStats);
+    backwardTurns++;
+  }
+
+  const unsigned long backwardMs = millis() - backwardStart;
+
+  startActivityForResult(
+      std::make_unique<EpubRenderBenchmarkActivity>(
+          renderer, mappedInput,
+          buildRenderBenchmarkReport(startSnapshot, aggregate, forwardTurns, forwardMs, backwardTurns, backwardMs)),
+      [this](const ActivityResult&) { requestUpdate(); });
+}
+
+std::string EpubReaderActivity::buildRenderBenchmarkReport(const LastRenderStats& startSnapshot,
+                                                           const BenchmarkAggregate& aggregate, const int forwardTurns,
+                                                           const unsigned long forwardMs, const int backwardTurns,
+                                                           const unsigned long backwardMs) const {
+  const LastRenderStats& endSnapshot = lastRenderStats.valid ? lastRenderStats : startSnapshot;
+
+  std::string report;
+  report.reserve(768);
+
+  auto appendLine = [&report](const std::string& line) {
+    if (!report.empty()) {
+      report += '\n';
+    }
+    report += line;
+  };
+
+  appendLine("Forward 10: " + std::to_string(forwardTurns) + " turns in " + std::to_string(forwardMs) + " ms");
+  if (forwardTurns > 0) {
+    appendLine("Forward avg: " + std::to_string(forwardMs / static_cast<unsigned long>(forwardTurns)) + " ms/turn");
+  }
+  appendLine("Backward 10: " + std::to_string(backwardTurns) + " turns in " + std::to_string(backwardMs) + " ms");
+  if (backwardTurns > 0) {
+    appendLine("Backward avg: " + std::to_string(backwardMs / static_cast<unsigned long>(backwardTurns)) + " ms/turn");
+  }
+  appendLine("Measured renders: " + std::to_string(aggregate.renderCount) + ", image pages " +
+             std::to_string(aggregate.imagePageCount) + ", cache rebuilds " +
+             std::to_string(aggregate.cacheRebuildCount));
+
+  appendLine("Start: spine " + std::to_string(startSnapshot.spineIndex) + ", page " +
+             std::to_string(startSnapshot.pageIndex + 1) + "/" + std::to_string(startSnapshot.pageCount));
+  appendLine("End: spine " + std::to_string(endSnapshot.spineIndex) + ", page " +
+             std::to_string(endSnapshot.pageIndex + 1) + "/" + std::to_string(endSnapshot.pageCount));
+  appendLine("Orientation: " +
+             std::string(orientationToString(static_cast<GfxRenderer::Orientation>(endSnapshot.orientation))));
+  appendLine("Viewport: " + std::to_string(endSnapshot.viewportWidth) + "x" +
+             std::to_string(endSnapshot.viewportHeight) + " px, margins T/R/B/L " +
+             std::to_string(endSnapshot.marginTop) + "/" + std::to_string(endSnapshot.marginRight) + "/" +
+             std::to_string(endSnapshot.marginBottom) + "/" + std::to_string(endSnapshot.marginLeft));
+  appendLine("Font: " + std::to_string(endSnapshot.effectiveFontId) + ", embedded CSS " +
+             std::string(endSnapshot.embeddedStyle ? "on" : "off") + ", images " +
+             std::to_string(endSnapshot.imageRendering) + ", AA " +
+             std::string(endSnapshot.textAntiAliasing ? "on" : "off"));
+  appendLine("Last page: images " + std::string(endSnapshot.hadImages ? "yes" : "no") + ", footnotes " +
+             std::to_string(endSnapshot.footnoteCount) + ", cache rebuilt " +
+             std::string(endSnapshot.cacheRebuilt ? "yes" : "no"));
+  if (aggregate.renderCount > 0) {
+    appendLine("Render avg/min/max: request " +
+               std::to_string(aggregate.totalRequestRenderMs / static_cast<unsigned long>(aggregate.renderCount)) +
+               "/" + std::to_string(aggregate.minRequestRenderMs) + "/" + std::to_string(aggregate.maxRequestRenderMs) +
+               " ms, core " +
+               std::to_string(aggregate.totalRenderMs / static_cast<unsigned long>(aggregate.renderCount)) + "/" +
+               std::to_string(aggregate.minRenderMs) + "/" + std::to_string(aggregate.maxRenderMs) + " ms");
+    appendLine("Aggregate loads: section " + std::to_string(aggregate.totalSectionLoadMs) + " ms, page " +
+               std::to_string(aggregate.totalPageLoadMs) + " ms, max footnotes " +
+               std::to_string(aggregate.maxFootnotes));
+    appendLine("Aggregate phases: prewarm " + std::to_string(aggregate.totalPhases.prewarmMs) + ", bw " +
+               std::to_string(aggregate.totalPhases.bwRenderMs) + ", display " +
+               std::to_string(aggregate.totalPhases.displayMs) + ", gray total " +
+               std::to_string(aggregate.totalPhases.grayLsbMs + aggregate.totalPhases.grayMsbMs +
+                              aggregate.totalPhases.grayDisplayMs));
+    appendLine("Aggregate font: hits " + std::to_string(aggregate.totalFontCacheHits) + ", misses " +
+               std::to_string(aggregate.totalFontCacheMisses) + ", decompress " +
+               std::to_string(aggregate.totalFontDecompressMs) + " ms");
+    appendLine("Aggregate glyph lookups: " + std::to_string(aggregate.totalFontGetBitmapCalls) + " calls, " +
+               std::to_string(aggregate.totalFontGetBitmapTimeUs) + " us total");
+    appendLine("Heap after render min/max: " + std::to_string(aggregate.minFreeHeapAfter) + "/" +
+               std::to_string(aggregate.maxFreeHeapAfter));
+  }
+  appendLine("Last render: request " + std::to_string(endSnapshot.requestRenderMs) + " ms, section load " +
+             std::to_string(endSnapshot.sectionLoadMs) + " ms, page load " + std::to_string(endSnapshot.pageLoadMs) +
+             " ms, render total " + std::to_string(endSnapshot.phases.totalMs) + " ms");
+  appendLine("Phases: prewarm " + std::to_string(endSnapshot.phases.prewarmMs) + ", bw " +
+             std::to_string(endSnapshot.phases.bwRenderMs) + ", display " +
+             std::to_string(endSnapshot.phases.displayMs) + ", store " + std::to_string(endSnapshot.phases.bwStoreMs) +
+             ", gray lsb " + std::to_string(endSnapshot.phases.grayLsbMs) + ", gray msb " +
+             std::to_string(endSnapshot.phases.grayMsbMs) + ", gray display " +
+             std::to_string(endSnapshot.phases.grayDisplayMs) + ", restore " +
+             std::to_string(endSnapshot.phases.bwRestoreMs));
+  appendLine("Font cache: hits " + std::to_string(endSnapshot.fontCacheHits) + ", misses " +
+             std::to_string(endSnapshot.fontCacheMisses) + ", decompress " +
+             std::to_string(endSnapshot.fontDecompressMs) + " ms, groups " +
+             std::to_string(endSnapshot.fontUniqueGroups));
+  appendLine("Font buffers: page " + std::to_string(endSnapshot.fontPageBufferBytes) + ", glyph table " +
+             std::to_string(endSnapshot.fontPageGlyphsBytes) + ", hot group " +
+             std::to_string(endSnapshot.fontHotGroupBytes) + ", peak temp " +
+             std::to_string(endSnapshot.fontPeakTempBytes));
+  appendLine("Glyph lookups: " + std::to_string(endSnapshot.fontGetBitmapCalls) + " calls, " +
+             std::to_string(endSnapshot.fontGetBitmapTimeUs) + " us total");
+  appendLine("Heap: before " + std::to_string(endSnapshot.freeHeapBefore) + "/" +
+             std::to_string(endSnapshot.largestFreeBlockBefore) + ", after " +
+             std::to_string(endSnapshot.freeHeapAfter) + "/" + std::to_string(endSnapshot.largestFreeBlockAfter));
+
+  return report;
+}
+
 void EpubReaderActivity::launchKOReaderSync(const SyncLaunchMode mode) {
   if (!epub) {
     return;
@@ -903,33 +1119,43 @@ int EpubReaderActivity::getEffectiveReaderFontId() const {
   }
 }
 
-void EpubReaderActivity::pageTurn(bool isForwardTurn) {
+bool EpubReaderActivity::stepPageState(const bool isForwardTurn) {
+  if (!epub || !section || section->pageCount <= 0) {
+    return false;
+  }
+
   if (isForwardTurn) {
     if (section->currentPage < section->pageCount - 1) {
       section->currentPage++;
+    } else if (currentSpineIndex + 1 < epub->getSpineItemsCount()) {
+      RenderLock lock(*this);
+      nextPageNumber = 0;
+      currentSpineIndex++;
+      section.reset();
     } else {
-      // We don't want to delete the section mid-render, so grab the semaphore
-      {
-        RenderLock lock(*this);
-        nextPageNumber = 0;
-        currentSpineIndex++;
-        section.reset();
-      }
+      return false;
     }
   } else {
     if (section->currentPage > 0) {
       section->currentPage--;
     } else if (currentSpineIndex > 0) {
-      // We don't want to delete the section mid-render, so grab the semaphore
-      {
-        RenderLock lock(*this);
-        nextPageNumber = UINT16_MAX;
-        currentSpineIndex--;
-        section.reset();
-      }
+      RenderLock lock(*this);
+      nextPageNumber = UINT16_MAX;
+      currentSpineIndex--;
+      section.reset();
+    } else {
+      return false;
     }
   }
+
   lastPageTurnTime = millis();
+  return true;
+}
+
+void EpubReaderActivity::pageTurn(bool isForwardTurn) {
+  if (!stepPageState(isForwardTurn)) {
+    return;
+  }
   requestUpdate();
 }
 
@@ -979,18 +1205,34 @@ void EpubReaderActivity::render(RenderLock&& lock) {
 
   const uint16_t viewportWidth = renderer.getScreenWidth() - orientedMarginLeft - orientedMarginRight;
   const uint16_t viewportHeight = renderer.getScreenHeight() - orientedMarginTop - orientedMarginBottom;
+  lastRenderStats = {};
+  lastRenderStats.orientation = static_cast<uint8_t>(renderer.getOrientation());
+  lastRenderStats.marginTop = orientedMarginTop;
+  lastRenderStats.marginRight = orientedMarginRight;
+  lastRenderStats.marginBottom = orientedMarginBottom;
+  lastRenderStats.marginLeft = orientedMarginLeft;
+  lastRenderStats.viewportWidth = viewportWidth;
+  lastRenderStats.viewportHeight = viewportHeight;
+  lastRenderStats.embeddedStyle = getEffectiveEmbeddedStyle();
+  lastRenderStats.imageRendering = getEffectiveImageRendering();
+  lastRenderStats.effectiveFontId = getEffectiveReaderFontId();
+  lastRenderStats.textAntiAliasing = SETTINGS.textAntiAliasing;
+  lastRenderStats.freeHeapBefore = esp_get_free_heap_size();
+  lastRenderStats.largestFreeBlockBefore = heap_caps_get_largest_free_block(MALLOC_CAP_8BIT | MALLOC_CAP_DEFAULT);
 
   if (!section) {
-    const bool embeddedStyle = getEffectiveEmbeddedStyle();
-    const uint8_t imageRendering = getEffectiveImageRendering();
+    const bool embeddedStyle = lastRenderStats.embeddedStyle;
+    const uint8_t imageRendering = lastRenderStats.imageRendering;
     const auto filepath = epub->getSpineItem(currentSpineIndex).href;
     LOG_DBG("ERS", "Loading file: %s, index: %d", filepath.c_str(), currentSpineIndex);
     section = std::make_unique<Section>(epub, currentSpineIndex, renderer);
+    const unsigned long sectionStart = millis();
 
     if (!section->loadSectionFile(getEffectiveReaderFontId(), SETTINGS.getReaderLineCompression(),
                                   SETTINGS.extraParagraphSpacing, SETTINGS.paragraphAlignment, viewportWidth,
                                   viewportHeight, SETTINGS.hyphenationEnabled, embeddedStyle, imageRendering)) {
       LOG_DBG("ERS", "Cache not found, building...");
+      lastRenderStats.cacheRebuilt = true;
 
       Rect popupRect{};
       const auto progressFn = [this, &popupRect](int progress) {
@@ -1011,6 +1253,7 @@ void EpubReaderActivity::render(RenderLock&& lock) {
     } else {
       LOG_DBG("ERS", "Cache found, skipping build...");
     }
+    lastRenderStats.sectionLoadMs = millis() - sectionStart;
 
     if (nextPageNumber == UINT16_MAX) {
       section->currentPage = section->pageCount - 1;
@@ -1097,7 +1340,9 @@ void EpubReaderActivity::render(RenderLock&& lock) {
   }
 
   {
+    const unsigned long pageLoadStart = millis();
     auto p = section->loadPageFromSectionFile();
+    lastRenderStats.pageLoadMs = millis() - pageLoadStart;
     if (!p) {
       LOG_ERR("ERS", "Failed to load page from SD - clearing section cache");
       section->clearCache();
@@ -1110,13 +1355,22 @@ void EpubReaderActivity::render(RenderLock&& lock) {
 
     // Collect footnotes from the loaded page
     currentPageFootnotes = std::move(p->footnotes);
+    lastRenderStats.hadImages = p->hasImages();
+    lastRenderStats.footnoteCount = static_cast<int>(currentPageFootnotes.size());
+    lastRenderStats.spineIndex = currentSpineIndex;
+    lastRenderStats.pageIndex = section->currentPage;
+    lastRenderStats.pageCount = section->pageCount;
 
     const auto start = millis();
     renderContents(std::move(p), orientedMarginTop, orientedMarginRight, orientedMarginBottom, orientedMarginLeft);
-    LOG_DBG("ERS", "Rendered page in %dms", millis() - start);
+    lastRenderStats.requestRenderMs = millis() - start;
+    LOG_DBG("ERS", "Rendered page in %dms", lastRenderStats.requestRenderMs);
   }
   silentIndexNextChapterIfNeeded(viewportWidth, viewportHeight);
   saveProgress(currentSpineIndex, section->currentPage, section->pageCount);
+  lastRenderStats.freeHeapAfter = esp_get_free_heap_size();
+  lastRenderStats.largestFreeBlockAfter = heap_caps_get_largest_free_block(MALLOC_CAP_8BIT | MALLOC_CAP_DEFAULT);
+  lastRenderStats.valid = true;
 
   if (pendingScreenshot) {
     pendingScreenshot = false;
@@ -1200,6 +1454,8 @@ void EpubReaderActivity::renderContents(std::unique_ptr<Page> page, const int or
   bool imagePageWithAA = page->hasImages() && SETTINGS.textAntiAliasing;
   bool forceHalfRefreshThisPage = pendingHalfRefreshAfterImagePage && SETTINGS.halfRefreshAfterImagePage;
   pendingHalfRefreshAfterImagePage = false;
+  lastRenderStats.imagePageWithAA = imagePageWithAA;
+  lastRenderStats.forcedHalfRefresh = forceHalfRefreshThisPage;
 
   logReaderMemSnapshot("before_bw_render");
   page->render(renderer, getEffectiveReaderFontId(), orientedMarginLeft, orientedMarginTop);
@@ -1283,6 +1539,10 @@ void EpubReaderActivity::renderContents(std::unique_ptr<Page> page, const int or
     logReaderMemSnapshot("bw_restore_end");
 
     const auto tEnd = millis();
+    lastRenderStats.usedGrayscale = true;
+    lastRenderStats.phases = {tPrewarm - t0,           tBwRender - tPrewarm,      tDisplay - tBwRender,
+                              tBwStore - tDisplay,     tGrayLsb - tBwStore,       tGrayMsb - tGrayLsb,
+                              tGrayDisplay - tGrayMsb, tBwRestore - tGrayDisplay, tEnd - t0};
     LOG_DBG("ERS",
             "Page render: prewarm=%lums bw_render=%lums display=%lums bw_store=%lums "
             "gray_lsb=%lums gray_msb=%lums gray_display=%lums bw_restore=%lums total=%lums",
@@ -1296,11 +1556,31 @@ void EpubReaderActivity::renderContents(std::unique_ptr<Page> page, const int or
     logReaderMemSnapshot("bw_restore_end");
 
     const auto tEnd = millis();
+    lastRenderStats.usedGrayscale = false;
+    lastRenderStats.phases = {
+        tPrewarm - t0, tBwRender - tPrewarm, tDisplay - tBwRender, tBwStore - tDisplay, 0, 0, 0, tBwRestore - tBwStore,
+        tEnd - t0};
     LOG_DBG("ERS",
             "Page render: prewarm=%lums bw_render=%lums display=%lums bw_store=%lums bw_restore=%lums total=%lums",
             tPrewarm - t0, tBwRender - tPrewarm, tDisplay - tBwRender, tBwStore - tDisplay, tBwRestore - tBwStore,
             tEnd - t0);
   }
+
+  if (auto* cacheManager = renderer.getFontCacheManager()) {
+    if (auto* decompressor = cacheManager->getDecompressor()) {
+      const auto& stats = decompressor->getStats();
+      lastRenderStats.fontCacheHits = stats.cacheHits;
+      lastRenderStats.fontCacheMisses = stats.cacheMisses;
+      lastRenderStats.fontDecompressMs = stats.decompressTimeMs;
+      lastRenderStats.fontUniqueGroups = stats.uniqueGroupsAccessed;
+      lastRenderStats.fontPageBufferBytes = stats.pageBufferBytes;
+      lastRenderStats.fontPageGlyphsBytes = stats.pageGlyphsBytes;
+      lastRenderStats.fontHotGroupBytes = stats.hotGroupBytes;
+      lastRenderStats.fontPeakTempBytes = stats.peakTempBytes;
+      lastRenderStats.fontGetBitmapTimeUs = stats.getBitmapTimeUs;
+      lastRenderStats.fontGetBitmapCalls = stats.getBitmapCalls;
+    }
+  }
 }
 
 void EpubReaderActivity::renderStatusBar() const {

src/activities/reader/EpubReaderActivity.h

@@ -38,6 +38,81 @@ class EpubReaderActivity final : public Activity {
   unsigned long lastPageTurnTime = 0UL;
   unsigned long pageTurnDuration = 0UL;
   bool pendingHalfRefreshAfterImagePage = false;
+  struct RenderPhaseStats {
+    unsigned long prewarmMs = 0UL;
+    unsigned long bwRenderMs = 0UL;
+    unsigned long displayMs = 0UL;
+    unsigned long bwStoreMs = 0UL;
+    unsigned long grayLsbMs = 0UL;
+    unsigned long grayMsbMs = 0UL;
+    unsigned long grayDisplayMs = 0UL;
+    unsigned long bwRestoreMs = 0UL;
+    unsigned long totalMs = 0UL;
+  };
+  struct LastRenderStats {
+    bool valid = false;
+    bool cacheRebuilt = false;
+    bool usedGrayscale = false;
+    bool hadImages = false;
+    bool imagePageWithAA = false;
+    bool forcedHalfRefresh = false;
+    uint8_t orientation = 0;
+    uint8_t imageRendering = 0;
+    bool embeddedStyle = false;
+    bool textAntiAliasing = false;
+    int effectiveFontId = 0;
+    int spineIndex = 0;
+    int pageIndex = 0;
+    int pageCount = 0;
+    int footnoteCount = 0;
+    int marginTop = 0;
+    int marginRight = 0;
+    int marginBottom = 0;
+    int marginLeft = 0;
+    uint16_t viewportWidth = 0;
+    uint16_t viewportHeight = 0;
+    unsigned long sectionLoadMs = 0UL;
+    unsigned long pageLoadMs = 0UL;
+    unsigned long requestRenderMs = 0UL;
+    RenderPhaseStats phases;
+    uint32_t freeHeapBefore = 0;
+    uint32_t largestFreeBlockBefore = 0;
+    uint32_t freeHeapAfter = 0;
+    uint32_t largestFreeBlockAfter = 0;
+    uint32_t fontCacheHits = 0;
+    uint32_t fontCacheMisses = 0;
+    uint32_t fontDecompressMs = 0;
+    uint16_t fontUniqueGroups = 0;
+    uint32_t fontPageBufferBytes = 0;
+    uint32_t fontPageGlyphsBytes = 0;
+    uint32_t fontHotGroupBytes = 0;
+    uint32_t fontPeakTempBytes = 0;
+    uint32_t fontGetBitmapTimeUs = 0;
+    uint32_t fontGetBitmapCalls = 0;
+  };
+  struct BenchmarkAggregate {
+    int renderCount = 0;
+    int imagePageCount = 0;
+    int cacheRebuildCount = 0;
+    int maxFootnotes = 0;
+    unsigned long totalRequestRenderMs = 0UL;
+    unsigned long minRequestRenderMs = 0UL;
+    unsigned long maxRequestRenderMs = 0UL;
+    unsigned long totalRenderMs = 0UL;
+    unsigned long minRenderMs = 0UL;
+    unsigned long maxRenderMs = 0UL;
+    unsigned long totalSectionLoadMs = 0UL;
+    unsigned long totalPageLoadMs = 0UL;
+    RenderPhaseStats totalPhases;
+    uint32_t totalFontCacheHits = 0;
+    uint32_t totalFontCacheMisses = 0;
+    uint32_t totalFontDecompressMs = 0;
+    uint32_t totalFontGetBitmapTimeUs = 0;
+    uint32_t totalFontGetBitmapCalls = 0;
+    uint32_t minFreeHeapAfter = 0;
+    uint32_t maxFreeHeapAfter = 0;
+  };
+  LastRenderStats lastRenderStats;
   // Signals that the next render should reposition within the newly loaded section
   // based on a cross-book percentage jump.
   bool pendingPercentJump = false;
@@ -95,7 +170,12 @@ class EpubReaderActivity final : public Activity {
   bool getEffectiveEmbeddedStyle() const;
   uint8_t getEffectiveImageRendering() const;
   int getEffectiveReaderFontId() const;
+  bool stepPageState(bool isForwardTurn);
   void pageTurn(bool isForwardTurn);
+  void runRenderBenchmark();
+  std::string buildRenderBenchmarkReport(const LastRenderStats& startSnapshot, const BenchmarkAggregate& aggregate,
+                                         int forwardTurns, unsigned long forwardMs, int backwardTurns,
+                                         unsigned long backwardMs) const;
 
   // Footnote navigation
   void navigateToHref(const std::string& href, bool savePosition = false);

src/activities/reader/EpubReaderMenuActivity.cpp

@@ -33,7 +33,7 @@ EpubReaderMenuActivity::EpubReaderMenuActivity(GfxRenderer& renderer, MappedInpu
 }
 
 void EpubReaderMenuActivity::buildMenuItems(bool hasFootnotes, bool hasStarredPages) {
-  menuItems.reserve(19);
+  menuItems.reserve(20);
 
   // --- Navigation ---
   menuItems.push_back(SettingInfo::Separator(StrId::STR_READER_NAVIGATION));
@@ -161,6 +161,8 @@ void EpubReaderMenuActivity::buildMenuItems(bool hasFootnotes, bool hasStarredPa
   menuItems.push_back(
       SettingInfo::Action(StrId::STR_DELETE_CACHE, SettingAction::None).withSubmenu(StrId::STR_READER_TOOLS));
   menuItems.push_back(SettingInfo::Action(StrId::STR_GO_HOME_BUTTON, SettingAction::None));
+  menuItems.push_back(
+      SettingInfo::Action(StrId::STR_RENDER_BENCHMARK, SettingAction::None).withSubmenu(StrId::STR_READER_TOOLS));
 }
 
 EpubReaderMenuActivity::MenuAction EpubReaderMenuActivity::actionForNameId(StrId nameId) {
@@ -195,6 +197,8 @@ EpubReaderMenuActivity::MenuAction EpubReaderMenuActivity::actionForNameId(StrId
       return MenuAction::DISPLAY_QR;
     case StrId::STR_DELETE_CACHE:
       return MenuAction::DELETE_CACHE;
+    case StrId::STR_RENDER_BENCHMARK:
+      return MenuAction::RENDER_BENCHMARK;
     case StrId::STR_GO_HOME_BUTTON:
       return MenuAction::GO_HOME;
     default:

src/activities/reader/EpubReaderMenuActivity.h

@@ -28,7 +28,8 @@ class EpubReaderMenuActivity final : public MenuListActivity {
     PUSH_LOCAL,
     STARRED_PAGES,
     STAR_PAGE,
-    DELETE_CACHE
+    DELETE_CACHE,
+    RENDER_BENCHMARK
   };
 
   explicit EpubReaderMenuActivity(GfxRenderer& renderer, MappedInputManager& mappedInput, const std::string& title,

src/activities/reader/EpubRenderBenchmarkActivity.cpp

@@ -0,0 +1,42 @@
+#include "EpubRenderBenchmarkActivity.h"
+
+#include <GfxRenderer.h>
+
+#include "components/UITheme.h"
+#include "fontIds.h"
+
+void EpubRenderBenchmarkActivity::onEnter() {
+  Activity::onEnter();
+  requestUpdate();
+}
+
+void EpubRenderBenchmarkActivity::loop() {
+  if (mappedInput.wasAnyPressed() || mappedInput.wasAnyReleased()) {
+    finish();
+  }
+}
+
+void EpubRenderBenchmarkActivity::render(RenderLock&&) {
+  renderer.clearScreen();
+
+  const Rect contentRect = UITheme::getContentRect(renderer, true, false);
+  const int titleY = contentRect.y + 12;
+  renderer.drawCenteredText(UI_12_FONT_ID, titleY, "Render Benchmark", true, EpdFontFamily::BOLD);
+
+  const int lineHeight = renderer.getLineHeight(UI_10_FONT_ID);
+  const int textTop = titleY + renderer.getLineHeight(UI_12_FONT_ID) + 14;
+  const int textWidth = contentRect.width - 20;
+  const auto lines = renderer.wrappedText(UI_10_FONT_ID, report.c_str(), textWidth, 48);
+
+  int y = textTop;
+  for (const auto& line : lines) {
+    if (y + lineHeight > contentRect.y + contentRect.height - 30) {
+      break;
+    }
+    renderer.drawText(UI_10_FONT_ID, contentRect.x + 10, y, line.c_str(), true);
+    y += lineHeight;
+  }
+
+  renderer.drawCenteredText(UI_10_FONT_ID, contentRect.y + contentRect.height - 18, "Press any button to close");
+  renderer.displayBuffer();
+}

src/activities/reader/EpubRenderBenchmarkActivity.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#include <string>
+
+#include "activities/Activity.h"
+
+class EpubRenderBenchmarkActivity final : public Activity {
+ public:
+  explicit EpubRenderBenchmarkActivity(GfxRenderer& renderer, MappedInputManager& mappedInput, std::string report)
+      : Activity("EpubRenderBenchmark", renderer, mappedInput), report(std::move(report)) {}
+
+  void onEnter() override;
+  void loop() override;
+  void render(RenderLock&&) override;
+
+ private:
+  std::string report;
+};