diff --git a/koreader-base b/koreader-base
index 6a0bced81..06ce7a616 160000
--- a/koreader-base
+++ b/koreader-base
@@ -1 +1 @@
-Subproject commit 6a0bced813af76301301dc65dbd8bacb46a617b4
+Subproject commit 06ce7a616da2fc66bf476927d7ef9eb08ec4aab8
diff --git a/spec/unit/benchmark_spec.lua b/spec/unit/benchmark_spec.lua
new file mode 100644
index 000000000..f4ad90971
--- /dev/null
+++ b/spec/unit/benchmark_spec.lua
@@ -0,0 +1,45 @@
+require "defaults"
+require "libs/libkoreader-luagettext"
+package.path = "?.lua;common/?.lua;frontend/?.lua"
+package.cpath = "?.so;common/?.so;/usr/lib/lua/?.so"
+
+-- global einkfb for Screen
+einkfb = require("ffi/framebuffer")
+-- do not show SDL window
+einkfb.dummy = true
+Blitbuffer = require("ffi/blitbuffer")
+util = require("ffi/util")
+
+local Screen = require("ui/screen")
+local DocSettings = require("docsettings")
+G_reader_settings = DocSettings:open(".reader")
+local DocumentRegistry = require("document/documentregistry")
+local DEBUG = require("dbg")
+
+-- screen should be inited for crengine
+Screen:init()
+
+function logDuration(filename, pageno, dur)
+    local file = io.open(filename, "a+")
+    if file then
+        if file:seek("end") == 0 then -- write the header only once
+            file:write("PAGE\tDUR\n")
+        end
+        file:write(string.format("%s\t%s\n", pageno, dur))
+        file:close()
+    end
+end
+
+describe("PDF rendering benchmark", function()
+    local sample_pdf = "spec/front/unit/data/sample.pdf"
+    local doc = DocumentRegistry:openDocument(sample_pdf)
+    for pageno = 1, doc.info.number_of_pages do
+        local secs, usecs = util.gettime()
+        assert.truthy(doc:renderPage(pageno, nil, 1, 0, 1.0, 0))
+        local nsecs, nusecs = util.gettime()
+        local dur = nsecs - secs + (nusecs - usecs) / 1000000
+        logDuration("pdf_rendering.log", pageno, dur)
+    end
+    doc:close()
+end)
+
diff --git a/spec/unit/document_spec.lua b/spec/unit/document_spec.lua
index 73ed68895..0ea747acd 100644
--- a/spec/unit/document_spec.lua
+++ b/spec/unit/document_spec.lua
@@ -50,11 +50,10 @@ describe("PDF document module", function()
 end)
 
 describe("EPUB document module", function()
-    local sample_epub = "spec/front/unit/data/leaves_of_grass.epub"
+    local sample_epub = "spec/front/unit/data/leaves.epub"
     it("should open document", function()
         doc = DocumentRegistry:openDocument(sample_epub)
         assert.truthy(doc)
-        doc:close()
     end)
     it("should close document", function()
         doc:close()
diff --git a/test/leaves.epub b/test/leaves.epub
new file mode 100644
index 000000000..afcf41e33
Binary files /dev/null and b/test/leaves.epub differ