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-rw-r--r--xpcom/threads/CPUUsageWatcher.cpp252
1 files changed, 252 insertions, 0 deletions
diff --git a/xpcom/threads/CPUUsageWatcher.cpp b/xpcom/threads/CPUUsageWatcher.cpp
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/CPUUsageWatcher.h"
+
+#include "prsystem.h"
+
+#ifdef XP_MACOSX
+# include <sys/resource.h>
+# include <mach/clock.h>
+# include <mach/mach_host.h>
+#endif
+
+#ifdef CPU_USAGE_WATCHER_ACTIVE
+# include "mozilla/BackgroundHangMonitor.h"
+#endif
+
+namespace mozilla {
+
+#ifdef CPU_USAGE_WATCHER_ACTIVE
+
+// Even if the machine only has one processor, tolerate up to 50%
+// external CPU usage.
+static const float kTolerableExternalCPUUsageFloor = 0.5f;
+
+struct CPUStats {
+ // The average CPU usage time, which can be summed across all cores in the
+ // system, or averaged between them. Whichever it is, it needs to be in the
+ // same units as updateTime.
+ uint64_t usageTime;
+ // A monotonically increasing value in the same units as usageTime, which can
+ // be used to determine the percentage of active vs idle time
+ uint64_t updateTime;
+};
+
+# ifdef XP_MACOSX
+
+static const uint64_t kMicrosecondsPerSecond = 1000000LL;
+static const uint64_t kNanosecondsPerMicrosecond = 1000LL;
+
+static uint64_t GetMicroseconds(timeval time) {
+ return ((uint64_t)time.tv_sec) * kMicrosecondsPerSecond +
+ (uint64_t)time.tv_usec;
+}
+
+static uint64_t GetMicroseconds(mach_timespec_t time) {
+ return ((uint64_t)time.tv_sec) * kMicrosecondsPerSecond +
+ ((uint64_t)time.tv_nsec) / kNanosecondsPerMicrosecond;
+}
+
+static Result<CPUStats, CPUUsageWatcherError> GetProcessCPUStats(
+ int32_t numCPUs) {
+ CPUStats result = {};
+ rusage usage;
+ int32_t rusageResult = getrusage(RUSAGE_SELF, &usage);
+ if (rusageResult == -1) {
+ return Err(GetProcessTimesError);
+ }
+ result.usageTime =
+ GetMicroseconds(usage.ru_utime) + GetMicroseconds(usage.ru_stime);
+
+ clock_serv_t realtimeClock;
+ kern_return_t errorResult =
+ host_get_clock_service(mach_host_self(), REALTIME_CLOCK, &realtimeClock);
+ if (errorResult != KERN_SUCCESS) {
+ return Err(GetProcessTimesError);
+ }
+ mach_timespec_t time;
+ errorResult = clock_get_time(realtimeClock, &time);
+ if (errorResult != KERN_SUCCESS) {
+ return Err(GetProcessTimesError);
+ }
+ result.updateTime = GetMicroseconds(time);
+
+ // getrusage will give us the sum of the values across all
+ // of our cores. Divide by the number of CPUs to get an average.
+ result.usageTime /= numCPUs;
+ return result;
+}
+
+static Result<CPUStats, CPUUsageWatcherError> GetGlobalCPUStats() {
+ CPUStats result = {};
+ host_cpu_load_info_data_t loadInfo;
+ mach_msg_type_number_t loadInfoCount = HOST_CPU_LOAD_INFO_COUNT;
+ kern_return_t statsResult =
+ host_statistics(mach_host_self(), HOST_CPU_LOAD_INFO,
+ (host_info_t)&loadInfo, &loadInfoCount);
+ if (statsResult != KERN_SUCCESS) {
+ return Err(HostStatisticsError);
+ }
+
+ result.usageTime = loadInfo.cpu_ticks[CPU_STATE_USER] +
+ loadInfo.cpu_ticks[CPU_STATE_NICE] +
+ loadInfo.cpu_ticks[CPU_STATE_SYSTEM];
+ result.updateTime = result.usageTime + loadInfo.cpu_ticks[CPU_STATE_IDLE];
+ return result;
+}
+
+# endif // XP_MACOSX
+
+# ifdef XP_WIN
+
+// A FILETIME represents the number of 100-nanosecond ticks since 1/1/1601 UTC
+uint64_t FiletimeToInteger(FILETIME filetime) {
+ return ((uint64_t)filetime.dwLowDateTime) | (uint64_t)filetime.dwHighDateTime
+ << 32;
+}
+
+Result<CPUStats, CPUUsageWatcherError> GetProcessCPUStats(int32_t numCPUs) {
+ CPUStats result = {};
+ FILETIME creationFiletime;
+ FILETIME exitFiletime;
+ FILETIME kernelFiletime;
+ FILETIME userFiletime;
+ bool success = GetProcessTimes(GetCurrentProcess(), &creationFiletime,
+ &exitFiletime, &kernelFiletime, &userFiletime);
+ if (!success) {
+ return Err(GetProcessTimesError);
+ }
+
+ result.usageTime =
+ FiletimeToInteger(kernelFiletime) + FiletimeToInteger(userFiletime);
+
+ FILETIME nowFiletime;
+ GetSystemTimeAsFileTime(&nowFiletime);
+ result.updateTime = FiletimeToInteger(nowFiletime);
+
+ result.usageTime /= numCPUs;
+
+ return result;
+}
+
+Result<CPUStats, CPUUsageWatcherError> GetGlobalCPUStats() {
+ CPUStats result = {};
+ FILETIME idleFiletime;
+ FILETIME kernelFiletime;
+ FILETIME userFiletime;
+ bool success = GetSystemTimes(&idleFiletime, &kernelFiletime, &userFiletime);
+
+ if (!success) {
+ return Err(GetSystemTimesError);
+ }
+
+ result.usageTime =
+ FiletimeToInteger(kernelFiletime) + FiletimeToInteger(userFiletime);
+ result.updateTime = result.usageTime + FiletimeToInteger(idleFiletime);
+
+ return result;
+}
+
+# endif // XP_WIN
+
+Result<Ok, CPUUsageWatcherError> CPUUsageWatcher::Init() {
+ mNumCPUs = PR_GetNumberOfProcessors();
+ if (mNumCPUs <= 0) {
+ mExternalUsageThreshold = 1.0f;
+ return Err(GetNumberOfProcessorsError);
+ }
+ mExternalUsageThreshold =
+ std::max(1.0f - 1.0f / (float)mNumCPUs, kTolerableExternalCPUUsageFloor);
+
+ CPUStats processTimes;
+ MOZ_TRY_VAR(processTimes, GetProcessCPUStats(mNumCPUs));
+ mProcessUpdateTime = processTimes.updateTime;
+ mProcessUsageTime = processTimes.usageTime;
+
+ CPUStats globalTimes;
+ MOZ_TRY_VAR(globalTimes, GetGlobalCPUStats());
+ mGlobalUpdateTime = globalTimes.updateTime;
+ mGlobalUsageTime = globalTimes.usageTime;
+
+ mInitialized = true;
+
+ CPUUsageWatcher* self = this;
+ NS_DispatchToMainThread(NS_NewRunnableFunction(
+ "CPUUsageWatcher::Init",
+ [=]() { BackgroundHangMonitor::RegisterAnnotator(*self); }));
+
+ return Ok();
+}
+
+void CPUUsageWatcher::Uninit() {
+ if (mInitialized) {
+ BackgroundHangMonitor::UnregisterAnnotator(*this);
+ }
+ mInitialized = false;
+}
+
+Result<Ok, CPUUsageWatcherError> CPUUsageWatcher::CollectCPUUsage() {
+ if (!mInitialized) {
+ return Ok();
+ }
+
+ mExternalUsageRatio = 0.0f;
+
+ CPUStats processTimes;
+ MOZ_TRY_VAR(processTimes, GetProcessCPUStats(mNumCPUs));
+ CPUStats globalTimes;
+ MOZ_TRY_VAR(globalTimes, GetGlobalCPUStats());
+
+ uint64_t processUsageDelta = processTimes.usageTime - mProcessUsageTime;
+ uint64_t processUpdateDelta = processTimes.updateTime - mProcessUpdateTime;
+ float processUsageNormalized =
+ processUsageDelta > 0
+ ? (float)processUsageDelta / (float)processUpdateDelta
+ : 0.0f;
+
+ uint64_t globalUsageDelta = globalTimes.usageTime - mGlobalUsageTime;
+ uint64_t globalUpdateDelta = globalTimes.updateTime - mGlobalUpdateTime;
+ float globalUsageNormalized =
+ globalUsageDelta > 0 ? (float)globalUsageDelta / (float)globalUpdateDelta
+ : 0.0f;
+
+ mProcessUsageTime = processTimes.usageTime;
+ mProcessUpdateTime = processTimes.updateTime;
+ mGlobalUsageTime = globalTimes.usageTime;
+ mGlobalUpdateTime = globalTimes.updateTime;
+
+ mExternalUsageRatio =
+ std::max(0.0f, globalUsageNormalized - processUsageNormalized);
+
+ return Ok();
+}
+
+void CPUUsageWatcher::AnnotateHang(BackgroundHangAnnotations& aAnnotations) {
+ if (!mInitialized) {
+ return;
+ }
+
+ if (mExternalUsageRatio > mExternalUsageThreshold) {
+ aAnnotations.AddAnnotation(u"ExternalCPUHigh"_ns, true);
+ }
+}
+
+#else // !CPU_USAGE_WATCHER_ACTIVE
+
+Result<Ok, CPUUsageWatcherError> CPUUsageWatcher::Init() { return Ok(); }
+
+void CPUUsageWatcher::Uninit() {}
+
+Result<Ok, CPUUsageWatcherError> CPUUsageWatcher::CollectCPUUsage() {
+ return Ok();
+}
+
+void CPUUsageWatcher::AnnotateHang(BackgroundHangAnnotations& aAnnotations) {}
+
+#endif // CPU_USAGE_WATCHER_ACTIVE
+
+} // namespace mozilla