IdleWakeups tool

tools/win/IdleWakeups/system_information_sampler.cpp

+// Copyright 2016 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 "stdafx.h"
+
+#include <algorithm>
+
+#include "system_information_sampler.h"
+
+// From ntdef.h
+typedef struct _UNICODE_STRING {
+  USHORT Length;
+  USHORT MaximumLength;
+  PWCH Buffer;
+} UNICODE_STRING;
+
+// From <wdm.h>
+typedef LONG KPRIORITY;
+typedef LONG KWAIT_REASON;  // Full definition is in wdm.h
+
+// From ntddk.h
+typedef struct _VM_COUNTERS {
+  SIZE_T PeakVirtualSize;
+  SIZE_T VirtualSize;
+  ULONG PageFaultCount;
+  // Padding here in 64-bit
+  SIZE_T PeakWorkingSetSize;
+  SIZE_T WorkingSetSize;
+  SIZE_T QuotaPeakPagedPoolUsage;
+  SIZE_T QuotaPagedPoolUsage;
+  SIZE_T QuotaPeakNonPagedPoolUsage;
+  SIZE_T QuotaNonPagedPoolUsage;
+  SIZE_T PagefileUsage;
+  SIZE_T PeakPagefileUsage;
+} VM_COUNTERS;
+
+// Two possibilities available from here:
+// http://stackoverflow.com/questions/28858849/where-is-system-information-class-defined
+
+typedef enum _SYSTEM_INFORMATION_CLASS {
+  SystemBasicInformation = 0,
+  SystemPerformanceInformation = 2,
+  SystemTimeOfDayInformation = 3,
+  SystemProcessInformation = 5,  // This is the number that we need
+  SystemProcessorPerformanceInformation = 8,
+  SystemInterruptInformation = 23,
+  SystemExceptionInformation = 33,
+  SystemRegistryQuotaInformation = 37,
+  SystemLookasideInformation = 45
+} SYSTEM_INFORMATION_CLASS;
+
+// https://msdn.microsoft.com/en-us/library/gg750647.aspx?f=255&MSPPError=-2147217396
+typedef struct {
+  HANDLE UniqueProcess;  // Actually process ID
+  HANDLE UniqueThread;   // Actually thread ID
+} CLIENT_ID;
+
+// From http://alax.info/blog/1182, with corrections and modifications
+// Originally from
+// http://undocumented.ntinternals.net/index.html?page=UserMode%2FUndocumented%20Functions%2FSystem%20Information%2FStructures%2FSYSTEM_THREAD.html
+struct SYSTEM_THREAD_INFORMATION {
+  ULONGLONG KernelTime;
+  ULONGLONG UserTime;
+  ULONGLONG CreateTime;
+  ULONG WaitTime;
+  // Padding here in 64-bit
+  PVOID StartAddress;
+  CLIENT_ID ClientId;
+  KPRIORITY Priority;
+  LONG BasePriority;
+  ULONG ContextSwitchCount;
+  ULONG State;
+  KWAIT_REASON WaitReason;
+};
+#if _M_X64
+static_assert(sizeof(SYSTEM_THREAD_INFORMATION) == 80,
+              "Structure size mismatch");
+#else
+static_assert(sizeof(SYSTEM_THREAD_INFORMATION) == 64,
+              "Structure size mismatch");
+#endif
+
+// From http://alax.info/blog/1182, with corrections and modifications
+// Originally from
+// http://undocumented.ntinternals.net/index.html?page=UserMode%2FUndocumented%20Functions%2FSystem%20Information%2FStructures%2FSYSTEM_THREAD.html
+struct SYSTEM_PROCESS_INFORMATION {
+  ULONG NextEntryOffset;
+  ULONG NumberOfThreads;
+  // http://processhacker.sourceforge.net/doc/struct___s_y_s_t_e_m___p_r_o_c_e_s_s___i_n_f_o_r_m_a_t_i_o_n.html
+  ULONGLONG WorkingSetPrivateSize;
+  ULONG HardFaultCount;
+  ULONG Reserved1;
+  ULONGLONG CycleTime;
+  ULONGLONG CreateTime;
+  ULONGLONG UserTime;
+  ULONGLONG KernelTime;
+  UNICODE_STRING ImageName;
+  KPRIORITY BasePriority;
+  HANDLE ProcessId;
+  HANDLE ParentProcessId;
+  ULONG HandleCount;
+  ULONG Reserved2[2];
+  // Padding here in 64-bit
+  VM_COUNTERS VirtualMemoryCounters;
+  size_t Reserved3;
+  IO_COUNTERS IoCounters;
+  SYSTEM_THREAD_INFORMATION Threads[1];
+};
+#if _M_X64
+static_assert(sizeof(SYSTEM_PROCESS_INFORMATION) == 336,
+              "Structure size mismatch");
+#else
+static_assert(sizeof(SYSTEM_PROCESS_INFORMATION) == 248,
+              "Structure size mismatch");
+#endif
+
+// ntstatus.h conflicts with windows.h so define this locally.
+#define STATUS_SUCCESS ((NTSTATUS)0x00000000L)
+#define STATUS_BUFFER_TOO_SMALL ((NTSTATUS)0xC0000023L)
+#define STATUS_INFO_LENGTH_MISMATCH ((NTSTATUS)0xC0000004L)
+
+typedef NTSTATUS(WINAPI* NTQUERYSYSTEMINFORMATION)(
+    SYSTEM_INFORMATION_CLASS SystemInformationClass,
+    PVOID SystemInformation,
+    ULONG SystemInformationLength,
+    PULONG ReturnLength);
+
+__declspec(noreturn) void oops(const char* pMessage) {
+  printf("%s\n", pMessage);
+  exit(0);
+}
+
+// Simple memory buffer wrapper for passing the data out of
+// QuerySystemProcessInformation.
+class ByteBuffer {
+ public:
+  explicit ByteBuffer(size_t capacity) : size_(0), capacity_(0) {
+    if (capacity > 0)
+      grow(capacity);
+  }
+
+  ~ByteBuffer() {}
+
+  BYTE* data() { return data_.get(); }
+
+  size_t size() { return size_; }
+
+  void set_size(size_t new_size) { size_ = new_size; }
+
+  size_t capacity() { return capacity_; }
+
+  void grow(size_t new_capacity) {
+    capacity_ = new_capacity;
+    data_.reset(new BYTE[new_capacity]);
+  }
+
+ private:
+  std::unique_ptr<BYTE[]> data_;
+  size_t size_;
+  size_t capacity_;
+
+  ByteBuffer& operator=(const ByteBuffer&) = delete;
+  ByteBuffer(const ByteBuffer&) = delete;
+};
+
+// Wrapper for NtQuerySystemProcessInformation with buffer reallocation logic.
+bool QuerySystemProcessInformation(ByteBuffer* buffer) {
+  typedef NTSTATUS(WINAPI * NTQUERYSYSTEMINFORMATION)(
+      SYSTEM_INFORMATION_CLASS SystemInformationClass, PVOID SystemInformation,
+      ULONG SystemInformationLength, PULONG ReturnLength);
+
+  HMODULE ntdll = GetModuleHandle(L"ntdll.dll");
+  if (!ntdll) {
+    oops("Couldn't load ntdll.dll");
+  }
+
+  NTQUERYSYSTEMINFORMATION nt_query_system_information_ptr =
+      reinterpret_cast<NTQUERYSYSTEMINFORMATION>(
+          GetProcAddress(ntdll, "NtQuerySystemInformation"));
+  if (!nt_query_system_information_ptr)
+    oops("Couldn't find NtQuerySystemInformation");
+
+  NTSTATUS result;
+
+  // There is a potential race condition between growing the buffer and new
+  // processes being created. Try a few times before giving up.
+  for (int i = 0; i < 10; i++) {
+    ULONG data_size = 0;
+    ULONG buffer_size = static_cast<ULONG>(buffer->capacity());
+    result = nt_query_system_information_ptr(
+        SystemProcessInformation, buffer->data(), buffer_size, &data_size);
+
+    if (result == STATUS_SUCCESS) {
+      buffer->set_size(data_size);
+      break;
+    }
+
+    if (result == STATUS_INFO_LENGTH_MISMATCH ||
+        result == STATUS_BUFFER_TOO_SMALL) {
+      // Insufficient buffer. Grow to the returned |data_size| plus 10% extra
+      // to avoid frequent reallocations and try again.
+      buffer->grow(static_cast<ULONG>(data_size * 1.1));
+    } else {
+      // An error other than the two above.
+      break;
+    }
+  }
+
+  return result == STATUS_SUCCESS;
+}
+
+SystemInformationSampler::SystemInformationSampler(
+    const wchar_t* process_name) {
+  lstrcpyn(target_process_name_, process_name,
+           sizeof(target_process_name_) / sizeof(wchar_t));
+
+  QueryPerformanceFrequency(&perf_frequency_);
+  QueryPerformanceCounter(&initial_counter_);
+}
+
+SystemInformationSampler::~SystemInformationSampler() {}
+
+std::unique_ptr<ProcessDataSnapshot> SystemInformationSampler::TakeSnapshot() {
+  // Preallocate the buffer with the size determined on the previous call to
+  // QuerySystemProcessInformation. This should be sufficient most of the time.
+  // QuerySystemProcessInformation will grow the buffer if necessary.
+  ByteBuffer data_buffer(previous_buffer_size_);
+
+  if (!QuerySystemProcessInformation(&data_buffer))
+    return std::unique_ptr<ProcessDataSnapshot>();

[stanisc, 2016/09/23 01:57:27]

Should fail here rather than return an empty snapshot.

+
+  previous_buffer_size_ = data_buffer.capacity();
+
+  std::unique_ptr<ProcessDataSnapshot> snapshot(new ProcessDataSnapshot);
+
+  LARGE_INTEGER perf_counter_value;
+  QueryPerformanceCounter(&perf_counter_value);
+  snapshot->timestamp = static_cast<double>(
+      (perf_counter_value.QuadPart - initial_counter_.QuadPart) /
+      perf_frequency_.QuadPart);
+
+  for (size_t offset = 0; offset < data_buffer.size();) {
+    auto pi = reinterpret_cast<const SYSTEM_PROCESS_INFORMATION*>(
+        data_buffer.data() + offset);
+
+    // Validate that the offset is valid and all needed data is within
+    // the buffer boundary.
+    if (offset + sizeof(SYSTEM_PROCESS_INFORMATION) > data_buffer.size())
+      break;
+    if (offset + sizeof(SYSTEM_PROCESS_INFORMATION) +
+            (pi->NumberOfThreads - 1) * sizeof(SYSTEM_THREAD_INFORMATION) >
+        data_buffer.size())
+      break;
+
+    if (pi->ImageName.Buffer) {
+      // Validate that the image name is within the buffer boundary.
+      // ImageName.Length seems to be in bytes rather than characters.
+      size_t image_name_offset =
+          reinterpret_cast<BYTE*>(pi->ImageName.Buffer) - data_buffer.data();
+      if (image_name_offset + pi->ImageName.Length > data_buffer.size())
+        break;
+
+      // Check if this is a chrome process. Ignore all other processes.
+      if (wcsncmp(target_process_name_filter(), pi->ImageName.Buffer,
+                  lstrlen(target_process_name_filter())) == 0) {
+        // Collect enough data to be able to do a diff between two snapshots.
+        // Some threads might stop or new threads might be created between two
+        // snapshots. If a thread with a large number of context switches gets
+        // terminated the total number of context switches for the process might
+        // go down and the delta would be negative.
+        // To avoid that we need to compare thread IDs between two snapshots and
+        // not count context switches for threads that are missing in the most
+        // recent snapshot.
+        ProcessData process_data;
+
+        process_data.cpu_time = pi->KernelTime + pi->UserTime;
+        process_data.working_set = pi->WorkingSetPrivateSize;
+
+        // Iterate over threads and store each thread's ID and number of context
+        // switches.
+        for (ULONG thread_index = 0; thread_index < pi->NumberOfThreads;
+             ++thread_index) {
+          const SYSTEM_THREAD_INFORMATION* ti = &pi->Threads[thread_index];
+          if (ti->ClientId.UniqueProcess != pi->ProcessId)
+            continue;
+
+          ThreadData thread_data;
+          thread_data.thread_id = ti->ClientId.UniqueThread;
+          thread_data.context_switches = ti->ContextSwitchCount;
+          process_data.threads.push_back(thread_data);
+        }
+
+        // Order thread data by thread ID to help diff two snapshots.
+        std::sort(process_data.threads.begin(), process_data.threads.end(),
+                  [](const ThreadData& l, const ThreadData r) {
+                    return l.thread_id < r.thread_id;
+                  });
+
+        snapshot->processes.insert(
+            std::make_pair(pi->ProcessId, std::move(process_data)));
+      }
+    }
+
+    // Check for end of the list.
+    if (!pi->NextEntryOffset)
+      break;
+
+    // Jump to the next entry.
+    offset += pi->NextEntryOffset;
+  }
+
+  return snapshot;
+}