Clamp texture queries to sane values.

cc/texture_uploader.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/texture_uploader.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/debug/alias.h"
@@ skipping 335 matching lines @@
 
 void TextureUploader::processQueries()
 {
     while (!m_pendingQueries.isEmpty()) {
         if (m_pendingQueries.first()->isPending())
             break;
 
         unsigned usElapsed = m_pendingQueries.first()->value();
         HISTOGRAM_CUSTOM_COUNTS("Renderer4.TextureGpuUploadTimeUS", usElapsed, 0, 100000, 50);
 
+        // Clamp the queries to saner values in case the queries fail.
+        usElapsed = std::max(1u, usElapsed);
+        usElapsed = std::min(5000u, usElapsed);

[reveman, 2012/12/04 21:24:09]

you might want to make the limit a bit higher. like 15000u. 3 textures per frame
is not far from the real upload performance on some android devices. also there
shouldn't be any problem with making this too high as the
ResourceUpdateController will make sure do perform at least one update per
frame.

+
         if (!m_pendingQueries.first()->isNonBlocking())
             m_numBlockingTextureUploads--;
 
         // Remove the min and max value from our history and insert the new one.
         double texturesPerSecond = 1.0 / (usElapsed * 1e-6);
         if (m_texturesPerSecondHistory.size() >= uploadHistorySizeMax) {
             m_texturesPerSecondHistory.erase(m_texturesPerSecondHistory.begin());
             m_texturesPerSecondHistory.erase(--m_texturesPerSecondHistory.end());
         }
         m_texturesPerSecondHistory.insert(texturesPerSecond);
 
         m_availableQueries.append(m_pendingQueries.takeFirst());
     }
 }
 
 }  // namespace cc