src/pagespeed/kernel/base/statistics.cc - incubator-pagespeed-debian - Git at Google

 /*
  * Copyright 2010 Google Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 // Author: jmarantz@google.com (Joshua Marantz)

 #include "pagespeed/kernel/base/statistics.h"

 #include <limits>
 #include <map>
 #include <memory>
 #include <utility>
 #include <vector>

 #include "base/logging.h"
 #include "pagespeed/kernel/base/abstract_mutex.h"
 #include "pagespeed/kernel/base/string.h"
 #include "pagespeed/kernel/base/string_util.h"
 #include "pagespeed/kernel/base/string_writer.h"
 #include "pagespeed/kernel/base/writer.h"

 namespace {
 // As we do fix size buckets, each bucket has the same height.
 const double kBarHeightPerBucket = 20;
 // Each bucket has different width, depends on the percentage of bucket value
 // out of total counts.
 // The width of a bucket is percentage_of_bucket_value * kBarWidthTotal.
 const double kBarWidthTotal = 400;
 }  // namespace
 namespace net_instaweb {

 class MessageHandler;

 Variable::~Variable() {
 }

 UpDownCounter::~UpDownCounter() {
 }

 int64 UpDownCounter::SetReturningPreviousValue(int64 value) {
   int64 previous_value = Get();
   Set(value);
   return previous_value;
 }

 MutexedScalar::~MutexedScalar() {
 }

 int64 MutexedScalar::Get() const {
   if (mutex() != NULL) {
     ScopedMutex hold_lock(mutex());
     return GetLockHeld();
   } else {
     return -1;
   }
 }

 void MutexedScalar::Set(int64 new_value) {
   if (mutex() != NULL) {
     ScopedMutex hold_lock(mutex());
     SetLockHeld(new_value);
   }
 }

 int64 MutexedScalar::SetReturningPreviousValue(int64 new_value) {
   if (mutex() != NULL) {
     ScopedMutex hold_lock(mutex());
     return SetReturningPreviousValueLockHeld(new_value);
   } else {
     return -1;
   }
 }

 int64 MutexedScalar::AddHelper(int64 delta) {
   if (mutex() != NULL) {
     ScopedMutex hold_lock(mutex());
     return AddLockHeld(delta);
   } else {
     return -1;
   }
 }

 void MutexedScalar::SetLockHeld(int64 new_value) {
   SetReturningPreviousValueLockHeld(new_value);
 }

 int64 MutexedScalar::AddLockHeld(int64 delta) {
   int64 value = GetLockHeld() + delta;
   SetLockHeld(value);
   return value;
 }

 Histogram::~Histogram() {
 }

 CountHistogram::CountHistogram(AbstractMutex* mutex)
     : mutex_(mutex), count_(0) {}

 CountHistogram::~CountHistogram() {
 }

 TimedVariable::~TimedVariable() {
 }

 FakeTimedVariable::FakeTimedVariable(StringPiece name, Statistics* stats)
     : var_(stats->AddVariable(name)) {
 }

 FakeTimedVariable::~FakeTimedVariable() {
 }

 void Histogram::WriteRawHistogramData(Writer* writer, MessageHandler* handler) {
   const char bucket_style[] = "<tr><td style=\"padding: 0 0 0 0.25em\">"
       "[</td><td style=\"text-align:right;padding:0 0.25em 0 0\">"
       "%s,</td><td style=text-align:right;padding: 0 0.25em\">%s)</td>";
   const char value_style[] = "<td style=\"text-align:right;padding:0 0.25em\">"
                              "%.f</td>";
   const char perc_style[] = "<td style=\"text-align:right;padding:0 0.25em\">"
                             "%.1f%%</td>";
   const char bar_style[] = "<td><div style=\"width: %.fpx;height:%.fpx;"
                            "background-color:blue\"></div></td>";
   double count = CountInternal();
   double perc = 0;
   double cumulative_perc = 0;
   // Write prefix of the table.
   writer->Write("<table>", handler);
   for (int i = 0, n = NumBuckets(); i < n; ++i) {
     double value = BucketCount(i);
     if (value == 0) {
       // We do not draw empty bucket.
       continue;
     }
     double lower_bound = BucketStart(i);
     double upper_bound = BucketLimit(i);

     GoogleString lower_bound_string = StringPrintf("%.0f", lower_bound);
     if (lower_bound == -std::numeric_limits<double>::infinity()) {
       lower_bound_string = "-&infin;";
     }
     GoogleString upper_bound_string = StringPrintf("%.0f", upper_bound);
     if (upper_bound == std::numeric_limits<double>::infinity()) {
       upper_bound_string = "&infin;";
     }

     perc = value * 100 / count;
     cumulative_perc += perc;
     GoogleString output = StrCat(
         StringPrintf(bucket_style, lower_bound_string.c_str(),
                      upper_bound_string.c_str()),
         StringPrintf(value_style, value),
         StringPrintf(perc_style, perc),
         StringPrintf(perc_style, cumulative_perc),
         StringPrintf(bar_style, (perc * kBarWidthTotal) / 100,
                      kBarHeightPerBucket));
     writer->Write(output, handler);
   }
   // Write suffix of the table.
   writer->Write("</table>", handler);
 }

 void Histogram::Render(int index, Writer* writer, MessageHandler* handler) {
   writer->Write(StringPrintf("<div id='hist_%d' style='display:none'>", index),
                 handler);

   // Don't hold a lock while calling the writer, as this can deadlock if
   // the writer itself winds up invoking pagespeed, causing the histogram
   // to be locked.  So buffer each histogram and release the lock before
   // passing it to writer.
   GoogleString buf;
   {
     ScopedMutex hold(lock());
     StringWriter string_writer(&buf);
     WriteRawHistogramData(&string_writer, handler);
   }

   writer->Write(buf, handler);
   writer->Write("</div>\n", handler);
 }

 Statistics::~Statistics() {
 }

 UpDownCounter* Statistics::AddGlobalUpDownCounter(const StringPiece& name) {
   return AddUpDownCounter(name);
 }

 namespace {

 const char kHistogramProlog[] =
     "<div>\n"
     "  <table>\n"
     "    <thead><tr>\n"
     "      <td>Histogram Name (click to view)</td>\n"
     "      <td>Count</td>\n"
     "      <td>Avg</td>\n"
     "      <td>StdDev</td>\n"
     "      <td>Min</td>\n"
     "      <td>Median</td>\n"
     "      <td>Max</td>\n"
     "      <td>90%</td>\n"
     "      <td>95%</td>\n"
     "      <td>99%</td>\n"
     "    </tr></thead><tbody>\n";

 const char kHistogramRowFormat[] =
     "      <tr id='hist_row_%d'>\n"
     "        <td><label><input type='radio' name='choose_histogram'%s\n"
     "                   onchange='setHistogram(%d)'>%s</label></td>\n"
     "        <td>%.0f</td><td>%.1f</td><td>%.1f</td>\n"  // count, avg, stddev
     "        <td>%.0f</td><td>%.0f</td><td>%.0f</td>\n"  // min, median, max
     "        <td>%.0f</td><td>%.0f</td><td>%.0f</td>\n"  // 90%, 95%, 99%
     "     </tr>\n";

 const char kHistogramEpilog[] =
     "    </tbody>\n"
     "  </table>\n"
     "</div>\n";

 const char kHistogramScript[] =
     "<script>\n"
     "  var currentHistogram = -1;\n"
     "  function setHistogram(id) {\n"
     "    var div = document.getElementById('hist_' + currentHistogram);\n"
     "    if (div) {\n"
     "      div.style.display = 'none';\n"
     "    }\n"
     "    div = document.getElementById('hist_' + id);\n"
     "    if (div) {\n"
     "      div.style.display = '';\n"
     "    }\n"
     "    var row = document.getElementById('hist_row_' + currentHistogram);\n"
     "    if (row) {\n"
     "      row.style.backgroundColor = 'white';\n"
     "    }\n"
     "    row = document.getElementById('hist_row_' + id);\n"
     "    if (row) {\n"
     "      row.style.backgroundColor = 'yellow';\n"
     "    }\n"
     "    currentHistogram = id;\n"
     "  }\n"
     "  setHistogram(0);\n"
     "</script>\n";

 }  // namespace

 void Statistics::RenderHistograms(Writer* writer, MessageHandler* handler) {
   StringVector hist_names = HistogramNames();  // includes empty ones.
   StringVector populated_histogram_names;
   std::vector<Histogram*> populated_histograms;

   // Find non-empty histograms.  Note that when the server first comes
   // up, there won't be any data in the histograms because there is no
   // traffic.  Other histograms may never be populated depending on
   // mod_pagespeed settings.  We pre-scan the histograms, capturing a
   // snapshot of the non-empty ones, because a histogram might become
   // non-empty asynchronously between the next two loops, and that
   // would skew indexing.
   for (int i = 0, n = hist_names.size(); i < n; ++i) {
     Histogram* hist = FindHistogram(hist_names[i]);

     // Exclude histograms with zero count.
     if (hist->Count() != 0) {
       populated_histograms.push_back(hist);
       populated_histogram_names.push_back(hist_names[i]);
     }
   }

   writer->Write("<hr/>", handler);

   // Write table data for each histogram.
   if (populated_histograms.empty()) {
     writer->Write("<em>No histogram data yet.  Refresh once there is "
                   "traffic.</em>", handler);
   } else {
     // Write the table header for all histograms.
     writer->Write(StringPiece(kHistogramProlog,
                               STATIC_STRLEN(kHistogramProlog)),
                   handler);

     // Write a row of the table data for each non-empty histogram.
     CHECK_EQ(populated_histogram_names.size(), populated_histograms.size());
     for (int i = 0, n = populated_histograms.size(); i < n; ++i) {
       Histogram* hist = populated_histograms[i];
       GoogleString row = hist->HtmlTableRow(populated_histogram_names[i], i);
       writer->Write(row, handler);
     }
     writer->Write(StringPiece(kHistogramEpilog,
                               STATIC_STRLEN(kHistogramEpilog)),
                   handler);

     // Render the non-empty histograms.
     for (int i = 0, n = populated_histograms.size(); i < n; ++i) {
       populated_histograms[i]->Render(i, writer, handler);
     }

     // Write the JavaScript to display the histograms and highlight the row
     // when selected.
     writer->Write(StringPiece(kHistogramScript,
                               STATIC_STRLEN(kHistogramScript)),
                   handler);
   }
   writer->Write("<hr/>\n", handler);
 }

 GoogleString Histogram::HtmlTableRow(const GoogleString& title, int index) {
   ScopedMutex hold(lock());
   return StringPrintf(
       kHistogramRowFormat,
       index,
       (index == 0) ? " selected" : "",
       index,
       title.c_str(),
       CountInternal(),
       AverageInternal(),
       StandardDeviationInternal(),
       MinimumInternal(),
       PercentileInternal(50),
       MaximumInternal(),
       PercentileInternal(90),
       PercentileInternal(95),
       PercentileInternal(99));
 }

 void Statistics::RenderTimedVariables(Writer* writer,
                                       MessageHandler* message_handler) {
   TimedVariable* timedvar = NULL;
   const GoogleString end("</table>\n<td>\n<td>\n");
   std::map<GoogleString, StringVector> group_map = TimedVariableMap();
   std::map<GoogleString, StringVector>::const_iterator p;
   // Export statistics in each group in one table.
   for (p = group_map.begin(); p != group_map.end(); ++p) {
     // Write table header for each group.
     const GoogleString begin = StrCat(
         "<p><table bgcolor=#eeeeff width=100%%>",
         "<tr align=center><td><font size=+2>", p->first,
         "</font></td></tr></table>",
         "</p>\n<td>\n<td>\n<td>\n<td>\n<td>\n",
         "<table bgcolor=#fff5ee frame=box cellspacing=1 cellpadding=2>\n",
         "<tr bgcolor=#eee5de><td>"
         "<form action=\"/statusz/reset\" method = \"post\">"
         "<input type=\"submit\" value = \"Reset Statistics\"></form></td>"
         "<th align=right>TenSec</th><th align=right>Minute</th>"
         "<th align=right>Hour</th><th align=right>Total</th></tr>");
     writer->Write(begin, message_handler);
     // Write each statistic as a row in the table.
     for (int i = 0, n = p->second.size(); i < n; ++i) {
       timedvar = FindTimedVariable(p->second[i]);
       const GoogleString content = StringPrintf("<tr><td> %s </td>"
           "<td align=right> %s </td><td align=right> %s </td>"
           "<td align=right> %s </td><td align=right> %s </td></tr>",
       p->second[i].c_str(),
       Integer64ToString(timedvar->Get(TimedVariable::TENSEC)).c_str(),
       Integer64ToString(timedvar->Get(TimedVariable::MINUTE)).c_str(),
       Integer64ToString(timedvar->Get(TimedVariable::HOUR)).c_str(),
       Integer64ToString(timedvar->Get(TimedVariable::START)).c_str());
       writer->Write(content, message_handler);
     }
     // Write table ending part.
     writer->Write(end, message_handler);
   }
 }

 int64 Statistics::LookupValue(StringPiece stat_name) {
   Variable* var = FindVariable(stat_name);
   if (var != NULL) {
     return var->Get();
   }
   UpDownCounter* counter = FindUpDownCounter(stat_name);
   if (counter != NULL) {
     return counter->Get();
   }
   TimedVariable* tvar = FindTimedVariable(stat_name);
   if (tvar != NULL) {
     return tvar->Get(TimedVariable::START);
   }
   LOG(FATAL) << "Could not find stat: " << stat_name;
   return 0;
 }

 }  // namespace net_instaweb
	/*
	* Copyright 2010 Google Inc.
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	// Author: jmarantz@google.com (Joshua Marantz)

	#include "pagespeed/kernel/base/statistics.h"

	#include <limits>
	#include <map>
	#include <memory>
	#include <utility>
	#include <vector>

	#include "base/logging.h"
	#include "pagespeed/kernel/base/abstract_mutex.h"
	#include "pagespeed/kernel/base/string.h"
	#include "pagespeed/kernel/base/string_util.h"
	#include "pagespeed/kernel/base/string_writer.h"
	#include "pagespeed/kernel/base/writer.h"

	namespace {
	// As we do fix size buckets, each bucket has the same height.
	const double kBarHeightPerBucket = 20;
	// Each bucket has different width, depends on the percentage of bucket value
	// out of total counts.
	// The width of a bucket is percentage_of_bucket_value * kBarWidthTotal.
	const double kBarWidthTotal = 400;
	} // namespace
	namespace net_instaweb {

	class MessageHandler;

	Variable::~Variable() {
	}

	UpDownCounter::~UpDownCounter() {
	}

	int64 UpDownCounter::SetReturningPreviousValue(int64 value) {
	int64 previous_value = Get();
	Set(value);
	return previous_value;
	}

	MutexedScalar::~MutexedScalar() {
	}

	int64 MutexedScalar::Get() const {
	if (mutex() != NULL) {
	ScopedMutex hold_lock(mutex());
	return GetLockHeld();
	} else {
	return -1;
	}
	}

	void MutexedScalar::Set(int64 new_value) {
	if (mutex() != NULL) {
	ScopedMutex hold_lock(mutex());
	SetLockHeld(new_value);
	}
	}

	int64 MutexedScalar::SetReturningPreviousValue(int64 new_value) {
	if (mutex() != NULL) {
	ScopedMutex hold_lock(mutex());
	return SetReturningPreviousValueLockHeld(new_value);
	} else {
	return -1;
	}
	}

	int64 MutexedScalar::AddHelper(int64 delta) {
	if (mutex() != NULL) {
	ScopedMutex hold_lock(mutex());
	return AddLockHeld(delta);
	} else {
	return -1;
	}
	}

	void MutexedScalar::SetLockHeld(int64 new_value) {
	SetReturningPreviousValueLockHeld(new_value);
	}

	int64 MutexedScalar::AddLockHeld(int64 delta) {
	int64 value = GetLockHeld() + delta;
	SetLockHeld(value);
	return value;
	}

	Histogram::~Histogram() {
	}

	CountHistogram::CountHistogram(AbstractMutex* mutex)
	: mutex_(mutex), count_(0) {}

	CountHistogram::~CountHistogram() {
	}

	TimedVariable::~TimedVariable() {
	}

	FakeTimedVariable::FakeTimedVariable(StringPiece name, Statistics* stats)
	: var_(stats->AddVariable(name)) {
	}

	FakeTimedVariable::~FakeTimedVariable() {
	}

	void Histogram::WriteRawHistogramData(Writer* writer, MessageHandler* handler) {
	const char bucket_style[] = "<tr><td style=\"padding: 0 0 0 0.25em\">"
	"[</td><td style=\"text-align:right;padding:0 0.25em 0 0\">"
	"%s,</td><td style=text-align:right;padding: 0 0.25em\">%s)</td>";
	const char value_style[] = "<td style=\"text-align:right;padding:0 0.25em\">"
	"%.f</td>";
	const char perc_style[] = "<td style=\"text-align:right;padding:0 0.25em\">"
	"%.1f%%</td>";
	const char bar_style[] = "<td><div style=\"width: %.fpx;height:%.fpx;"
	"background-color:blue\"></div></td>";
	double count = CountInternal();
	double perc = 0;
	double cumulative_perc = 0;
	// Write prefix of the table.
	writer->Write("<table>", handler);
	for (int i = 0, n = NumBuckets(); i < n; ++i) {
	double value = BucketCount(i);
	if (value == 0) {
	// We do not draw empty bucket.
	continue;
	}
	double lower_bound = BucketStart(i);
	double upper_bound = BucketLimit(i);

	GoogleString lower_bound_string = StringPrintf("%.0f", lower_bound);
	if (lower_bound == -std::numeric_limits<double>::infinity()) {
	lower_bound_string = "-∞";
	}
	GoogleString upper_bound_string = StringPrintf("%.0f", upper_bound);
	if (upper_bound == std::numeric_limits<double>::infinity()) {
	upper_bound_string = "∞";
	}

	perc = value * 100 / count;
	cumulative_perc += perc;
	GoogleString output = StrCat(
	StringPrintf(bucket_style, lower_bound_string.c_str(),
	upper_bound_string.c_str()),
	StringPrintf(value_style, value),
	StringPrintf(perc_style, perc),
	StringPrintf(perc_style, cumulative_perc),
	StringPrintf(bar_style, (perc * kBarWidthTotal) / 100,
	kBarHeightPerBucket));
	writer->Write(output, handler);
	}
	// Write suffix of the table.
	writer->Write("</table>", handler);
	}

	void Histogram::Render(int index, Writer* writer, MessageHandler* handler) {
	writer->Write(StringPrintf("<div id='hist_%d' style='display:none'>", index),
	handler);

	// Don't hold a lock while calling the writer, as this can deadlock if
	// the writer itself winds up invoking pagespeed, causing the histogram
	// to be locked. So buffer each histogram and release the lock before
	// passing it to writer.
	GoogleString buf;
	{
	ScopedMutex hold(lock());
	StringWriter string_writer(&buf);
	WriteRawHistogramData(&string_writer, handler);
	}

	writer->Write(buf, handler);
	writer->Write("</div>\n", handler);
	}

	Statistics::~Statistics() {
	}

	UpDownCounter* Statistics::AddGlobalUpDownCounter(const StringPiece& name) {
	return AddUpDownCounter(name);
	}

	namespace {

	const char kHistogramProlog[] =
	"<div>\n"
	" <table>\n"
	" <thead><tr>\n"
	" <td>Histogram Name (click to view)</td>\n"
	" <td>Count</td>\n"
	" <td>Avg</td>\n"
	" <td>StdDev</td>\n"
	" <td>Min</td>\n"
	" <td>Median</td>\n"
	" <td>Max</td>\n"
	" <td>90%</td>\n"
	" <td>95%</td>\n"
	" <td>99%</td>\n"
	" </tr></thead><tbody>\n";

	const char kHistogramRowFormat[] =
	" <tr id='hist_row_%d'>\n"
	" <td><label><input type='radio' name='choose_histogram'%s\n"
	" onchange='setHistogram(%d)'>%s</label></td>\n"
	" <td>%.0f</td><td>%.1f</td><td>%.1f</td>\n" // count, avg, stddev
	" <td>%.0f</td><td>%.0f</td><td>%.0f</td>\n" // min, median, max
	" <td>%.0f</td><td>%.0f</td><td>%.0f</td>\n" // 90%, 95%, 99%
	" </tr>\n";

	const char kHistogramEpilog[] =
	" </tbody>\n"
	" </table>\n"
	"</div>\n";

	const char kHistogramScript[] =
	"<script>\n"
	" var currentHistogram = -1;\n"
	" function setHistogram(id) {\n"
	" var div = document.getElementById('hist_' + currentHistogram);\n"
	" if (div) {\n"
	" div.style.display = 'none';\n"
	" }\n"
	" div = document.getElementById('hist_' + id);\n"
	" if (div) {\n"
	" div.style.display = '';\n"
	" }\n"
	" var row = document.getElementById('hist_row_' + currentHistogram);\n"
	" if (row) {\n"
	" row.style.backgroundColor = 'white';\n"
	" }\n"
	" row = document.getElementById('hist_row_' + id);\n"
	" if (row) {\n"
	" row.style.backgroundColor = 'yellow';\n"
	" }\n"
	" currentHistogram = id;\n"
	" }\n"
	" setHistogram(0);\n"
	"</script>\n";

	} // namespace

	void Statistics::RenderHistograms(Writer* writer, MessageHandler* handler) {
	StringVector hist_names = HistogramNames(); // includes empty ones.
	StringVector populated_histogram_names;
	std::vector<Histogram*> populated_histograms;

	// Find non-empty histograms. Note that when the server first comes
	// up, there won't be any data in the histograms because there is no
	// traffic. Other histograms may never be populated depending on
	// mod_pagespeed settings. We pre-scan the histograms, capturing a
	// snapshot of the non-empty ones, because a histogram might become
	// non-empty asynchronously between the next two loops, and that
	// would skew indexing.
	for (int i = 0, n = hist_names.size(); i < n; ++i) {
	Histogram* hist = FindHistogram(hist_names[i]);

	// Exclude histograms with zero count.
	if (hist->Count() != 0) {
	populated_histograms.push_back(hist);
	populated_histogram_names.push_back(hist_names[i]);
	}
	}

	writer->Write("<hr/>", handler);

	// Write table data for each histogram.
	if (populated_histograms.empty()) {
	writer->Write("<em>No histogram data yet. Refresh once there is "
	"traffic.</em>", handler);
	} else {
	// Write the table header for all histograms.
	writer->Write(StringPiece(kHistogramProlog,
	STATIC_STRLEN(kHistogramProlog)),
	handler);

	// Write a row of the table data for each non-empty histogram.
	CHECK_EQ(populated_histogram_names.size(), populated_histograms.size());
	for (int i = 0, n = populated_histograms.size(); i < n; ++i) {
	Histogram* hist = populated_histograms[i];
	GoogleString row = hist->HtmlTableRow(populated_histogram_names[i], i);
	writer->Write(row, handler);
	}
	writer->Write(StringPiece(kHistogramEpilog,
	STATIC_STRLEN(kHistogramEpilog)),
	handler);

	// Render the non-empty histograms.
	for (int i = 0, n = populated_histograms.size(); i < n; ++i) {
	populated_histograms[i]->Render(i, writer, handler);
	}

	// Write the JavaScript to display the histograms and highlight the row
	// when selected.
	writer->Write(StringPiece(kHistogramScript,
	STATIC_STRLEN(kHistogramScript)),
	handler);
	}
	writer->Write("<hr/>\n", handler);
	}

	GoogleString Histogram::HtmlTableRow(const GoogleString& title, int index) {
	ScopedMutex hold(lock());
	return StringPrintf(
	kHistogramRowFormat,
	index,
	(index == 0) ? " selected" : "",
	index,
	title.c_str(),
	CountInternal(),
	AverageInternal(),
	StandardDeviationInternal(),
	MinimumInternal(),
	PercentileInternal(50),
	MaximumInternal(),
	PercentileInternal(90),
	PercentileInternal(95),
	PercentileInternal(99));
	}

	void Statistics::RenderTimedVariables(Writer* writer,
	MessageHandler* message_handler) {
	TimedVariable* timedvar = NULL;
	const GoogleString end("</table>\n<td>\n<td>\n");
	std::map<GoogleString, StringVector> group_map = TimedVariableMap();
	std::map<GoogleString, StringVector>::const_iterator p;
	// Export statistics in each group in one table.
	for (p = group_map.begin(); p != group_map.end(); ++p) {
	// Write table header for each group.
	const GoogleString begin = StrCat(
	"<p><table bgcolor=#eeeeff width=100%%>",
	"<tr align=center><td><font size=+2>", p->first,
	"</font></td></tr></table>",
	"</p>\n<td>\n<td>\n<td>\n<td>\n<td>\n",
	"<table bgcolor=#fff5ee frame=box cellspacing=1 cellpadding=2>\n",
	"<tr bgcolor=#eee5de><td>"
	"<form action=\"/statusz/reset\" method = \"post\">"
	"<input type=\"submit\" value = \"Reset Statistics\"></form></td>"
	"<th align=right>TenSec</th><th align=right>Minute</th>"
	"<th align=right>Hour</th><th align=right>Total</th></tr>");
	writer->Write(begin, message_handler);
	// Write each statistic as a row in the table.
	for (int i = 0, n = p->second.size(); i < n; ++i) {
	timedvar = FindTimedVariable(p->second[i]);
	const GoogleString content = StringPrintf("<tr><td> %s </td>"
	"<td align=right> %s </td><td align=right> %s </td>"
	"<td align=right> %s </td><td align=right> %s </td></tr>",
	p->second[i].c_str(),
	Integer64ToString(timedvar->Get(TimedVariable::TENSEC)).c_str(),
	Integer64ToString(timedvar->Get(TimedVariable::MINUTE)).c_str(),
	Integer64ToString(timedvar->Get(TimedVariable::HOUR)).c_str(),
	Integer64ToString(timedvar->Get(TimedVariable::START)).c_str());
	writer->Write(content, message_handler);
	}
	// Write table ending part.
	writer->Write(end, message_handler);
	}
	}

	int64 Statistics::LookupValue(StringPiece stat_name) {
	Variable* var = FindVariable(stat_name);
	if (var != NULL) {
	return var->Get();
	}
	UpDownCounter* counter = FindUpDownCounter(stat_name);
	if (counter != NULL) {
	return counter->Get();
	}
	TimedVariable* tvar = FindTimedVariable(stat_name);
	if (tvar != NULL) {
	return tvar->Get(TimedVariable::START);
	}
	LOG(FATAL) << "Could not find stat: " << stat_name;
	return 0;
	}

	} // namespace net_instaweb