1 // Copyright (c) 2012 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 // Dumps CPU and IO stats to a file at a regular interval. 6 // 7 // Output may be post processed by host to get top/iotop style information. 8 9 #include <signal.h> 10 #include <unistd.h> 11 12 #include <fstream> 13 #include <string> 14 #include <vector> 15 16 #include "base/command_line.h" 17 #include "base/file_util.h" 18 #include "base/strings/string_split.h" 19 20 namespace { 21 22 const char kIOStatsPath[] = "/proc/diskstats"; 23 const char kCPUStatsPath[] = "/proc/stat"; 24 25 class DeviceStatsMonitor { 26 public: 27 explicit DeviceStatsMonitor(const std::string& out_path) 28 : out_path_(out_path), 29 record_(true) { 30 CHECK(!out_path_.empty()); 31 samples_.reserve(1024 * 1024); 32 } 33 34 // Records stats continuously at |hz| cycles per second util 35 // StopRecordingAndDumpStats() is called. 36 // 37 // Yes, this buffers everything in memory, so it cannot be used for extended 38 // durations without OOM. But that beats writing during the trace which 39 // would affect the results. 40 void Start(int hz) { 41 const int sample_interval = 1000000 / hz; 42 const base::FilePath io_stats_path(kIOStatsPath); 43 const base::FilePath cpu_stats_path(kCPUStatsPath); 44 std::string out; 45 while (record_) { 46 out.clear(); 47 CHECK(file_util::ReadFileToString(io_stats_path, &out)); 48 CHECK(file_util::ReadFileToString(cpu_stats_path, &out)); 49 samples_.push_back(out); 50 usleep(sample_interval); 51 } 52 } 53 54 // Stops recording and saves samples to file. 55 void StopAndDumpStats() { 56 record_ = false; 57 usleep(250 * 1000); 58 std::ofstream out_stream; 59 out_stream.open(out_path_.value().c_str(), std::ios::out); 60 for (std::vector<std::string>::const_iterator i = samples_.begin(); 61 i != samples_.end(); ++i) { 62 out_stream << i->c_str() << std::endl; 63 } 64 out_stream.close(); 65 } 66 67 private: 68 const base::FilePath out_path_; 69 std::vector<std::string> samples_; 70 bool record_; 71 72 DISALLOW_COPY_AND_ASSIGN(DeviceStatsMonitor); 73 }; 74 75 DeviceStatsMonitor* g_device_stats_monitor = NULL; 76 77 void SigTermHandler(int unused) { 78 printf("Stopping device stats monitor\n"); 79 g_device_stats_monitor->StopAndDumpStats(); 80 } 81 82 } // namespace 83 84 int main(int argc, char** argv) { 85 const int kDefaultHz = 20; 86 87 CommandLine command_line(argc, argv); 88 CommandLine::StringVector args = command_line.GetArgs(); 89 if (command_line.HasSwitch("h") || command_line.HasSwitch("help") || 90 args.size() != 1) { 91 printf("Usage: %s OUTPUT_FILE\n" 92 " --hz=HZ Number of samples/second. default=%d\n", 93 argv[0], kDefaultHz); 94 return 1; 95 } 96 97 int hz = command_line.HasSwitch("hz") ? 98 atoi(command_line.GetSwitchValueNative("hz").c_str()) : 99 kDefaultHz; 100 101 printf("Starting device stats monitor\n"); 102 g_device_stats_monitor = new DeviceStatsMonitor(args[0]); 103 signal(SIGTERM, SigTermHandler); 104 g_device_stats_monitor->Start(hz); 105 delete g_device_stats_monitor; 106 107 return 0; 108 } 109
