net/base/mime_sniffer_perftest.cc

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "net/base/mime_sniffer.h"
   6
   7 #include <vector>
   8
   9 #include "base/bits.h"
  10 #include "base/logging.h"
  11 #include "base/timer/elapsed_timer.h"
  12 #include "testing/gtest/include/gtest/gtest.h"
  13
  14 namespace net {
  15 namespace {
  16
  17 // This text is supposed to be representative of a plain text file the browser
  18 // might encounter, including a variation in line lengths and blank
  19 // lines. CRLF is used as the line-terminator to make it slightly more
  20 // difficult. It is roughly 1KB.
  21 const char kRepresentativePlainText[] =
  22     "The Tragedie of Hamlet\r\n"
  23     "\r\n"
  24     "Actus Primus. Scoena Prima.\r\n"
  25     "\r\n"
  26     "Enter Barnardo and Francisco two Centinels.\r\n"
  27     "\r\n"
  28     "  Barnardo. Who's there?\r\n"
  29     "  Fran. Nay answer me: Stand & vnfold\r\n"
  30     "your selfe\r\n"
  31     "\r\n"
  32     "   Bar. Long liue the King\r\n"
  33     "\r\n"
  34     "   Fran. Barnardo?\r\n"
  35     "  Bar. He\r\n"
  36     "\r\n"
  37     "   Fran. You come most carefully vpon your houre\r\n"
  38     "\r\n"
  39     "   Bar. 'Tis now strook twelue, get thee to bed Francisco\r\n"
  40     "\r\n"
  41     "   Fran. For this releefe much thankes: 'Tis bitter cold,\r\n"
  42     "And I am sicke at heart\r\n"
  43     "\r\n"
  44     "   Barn. Haue you had quiet Guard?\r\n"
  45     "  Fran. Not a Mouse stirring\r\n"
  46     "\r\n"
  47     "   Barn. Well, goodnight. If you do meet Horatio and\r\n"
  48     "Marcellus, the Riuals of my Watch, bid them make hast.\r\n"
  49     "Enter Horatio and Marcellus.\r\n"
  50     "\r\n"
  51     "  Fran. I thinke I heare them. Stand: who's there?\r\n"
  52     "  Hor. Friends to this ground\r\n"
  53     "\r\n"
  54     "   Mar. And Leige-men to the Dane\r\n"
  55     "\r\n"
  56     "   Fran. Giue you good night\r\n"
  57     "\r\n"
  58     "   Mar. O farwel honest Soldier, who hath relieu'd you?\r\n"
  59     "  Fra. Barnardo ha's my place: giue you goodnight.\r\n"
  60     "\r\n"
  61     "Exit Fran.\r\n"
  62     "\r\n"
  63     "  Mar. Holla Barnardo\r\n"
  64     "\r\n"
  65     "   Bar. Say, what is Horatio there?\r\n"
  66     "  Hor. A peece of him\r\n"
  67     "\r\n"
  68     "   Bar. Welcome Horatio, welcome good Marcellus\r\n"
  69     "\r\n";
  70
  71 void RunLooksLikeBinary(const std::string& plaintext, size_t iterations) {
  72   bool looks_like_binary = false;
  73   for (size_t i = 0; i < iterations; ++i) {
  74     if (LooksLikeBinary(&plaintext[0], plaintext.size()))
  75       looks_like_binary = true;
  76   }
  77   CHECK(!looks_like_binary);
  78 }
  79
  80 TEST(MimeSnifferTest, PlainTextPerfTest) {
  81   // Android systems have a relatively small CPU cache (512KB to 2MB).
  82   // It is better if the test data fits in cache so that we are not just
  83   // testing bus bandwidth.
  84   const size_t kTargetSize = 1 << 18;  // 256KB
  85   const size_t kWarmupIterations = 16;
  86   const size_t kMeasuredIterations = 1 << 15;
  87   std::string plaintext = kRepresentativePlainText;
  88   // The purpose of the static_cast<size_t>() here is to prevent MSVC from
  89   // complaining about an implicit promotion to 64 bits when compiling 64-bit.
  90   size_t expected_size =
  91       plaintext.size() *
  92       static_cast<size_t>(
  93           1u << base::bits::Log2Ceiling(kTargetSize / plaintext.size()));
  94   plaintext.reserve(expected_size);
  95   while (plaintext.size() < kTargetSize)
  96     plaintext += plaintext;
  97   DCHECK_EQ(expected_size, plaintext.size());
  98   RunLooksLikeBinary(plaintext, kWarmupIterations);
  99   base::ElapsedTimer elapsed_timer;
 100   RunLooksLikeBinary(plaintext, kMeasuredIterations);
 101   LOG(INFO) << (elapsed_timer.Elapsed().InMicroseconds() * 1000 * 1024 /
 102                 (static_cast<int64_t>(plaintext.size()) * kMeasuredIterations))
 103             << "ns per KB";
 104 }
 105
 106 }  // namespace net
 107 }  // namespace