1 /* 2 * Copyright (c) 2017, 2019, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "jfr/periodic/jfrThreadCPULoadEvent.hpp" 27 #include "jfr/recorder/access/jfrThreadData.hpp" 28 #include "jfr/utilities/jfrTraceTime.hpp" 29 #include "utilities/globalDefinitions.hpp" 30 #include "runtime/os.hpp" 31 #include "runtime/thread.inline.hpp" 32 #include "tracefiles/traceEventClasses.hpp" 33 34 jlong JfrThreadCPULoadEvent::get_wallclock_time() { 35 return os::javaTimeNanos(); 36 } 37 38 int JfrThreadCPULoadEvent::_last_active_processor_count = 0; 39 40 int JfrThreadCPULoadEvent::get_processor_count() { 41 int cur_processor_count = os::active_processor_count(); 42 int last_processor_count = _last_active_processor_count; 43 _last_active_processor_count = cur_processor_count; 44 45 // If the number of processors decreases, we don't know at what point during 46 // the sample interval this happened, so use the largest number to try 47 // to avoid percentages above 100% 48 return MAX2(cur_processor_count, last_processor_count); 49 } 50 51 // Returns false if the thread has not been scheduled since the last call to updateEvent 52 // (i.e. the delta for both system and user time is 0 milliseconds) 53 bool JfrThreadCPULoadEvent::update_event(EventThreadCPULoad& event, JavaThread* thread, jlong cur_wallclock_time, int processor_count) { 54 JfrThreadData* thread_data = thread->trace_data(); 55 56 jlong cur_cpu_time = os::thread_cpu_time(thread, true); 57 jlong prev_cpu_time = thread_data->get_cpu_time(); 58 59 jlong prev_wallclock_time = thread_data->get_wallclock_time(); 60 thread_data->set_wallclock_time(cur_wallclock_time); 61 62 // Threshold of 1 ms 63 if (cur_cpu_time - prev_cpu_time < 1 * NANOSECS_PER_MILLISEC) { 64 return false; 65 } 66 67 jlong cur_user_time = os::thread_cpu_time(thread, false); 68 jlong prev_user_time = thread_data->get_user_time(); 69 70 jlong cur_system_time = cur_cpu_time - cur_user_time; 71 jlong prev_system_time = prev_cpu_time - prev_user_time; 72 73 // The user and total cpu usage clocks can have different resolutions, which can 74 // make us see decreasing system time. Ensure time doesn't go backwards. 75 if (prev_system_time > cur_system_time) { 76 cur_system_time = prev_system_time; 77 } 78 79 jlong user_time = cur_user_time - prev_user_time; 80 jlong system_time = cur_system_time - prev_system_time; 81 jlong wallclock_time = cur_wallclock_time - prev_wallclock_time; 82 jlong total_available_time = wallclock_time * processor_count; 83 84 // Avoid reporting percentages above the theoretical max 85 if (user_time + system_time > wallclock_time) { 86 jlong excess = user_time + system_time - wallclock_time; 87 if (user_time > excess) { 88 user_time -= excess; 89 cur_user_time -= excess; 90 } else { 91 excess -= user_time; 92 user_time = 0; 93 cur_user_time = 0; 94 system_time -= excess; 95 cur_system_time -= excess; 96 } 97 } 98 event.set_user(total_available_time > 0 ? (double)user_time / total_available_time : 0); 99 event.set_system(total_available_time > 0 ? (double)system_time / total_available_time : 0); 100 thread_data->set_user_time(cur_user_time); 101 thread_data->set_cpu_time(cur_cpu_time); 102 return true; 103 } 104 105 void JfrThreadCPULoadEvent::send_events() { 106 Thread* periodic_thread = Thread::current(); 107 JfrThreadData* const periodic_trace_data = periodic_thread->trace_data(); 108 traceid periodic_thread_id = periodic_trace_data->thread_id(); 109 const int processor_count = JfrThreadCPULoadEvent::get_processor_count(); 110 JfrTraceTime event_time = JfrTraceTime::now(); 111 jlong cur_wallclock_time = JfrThreadCPULoadEvent::get_wallclock_time(); 112 113 JavaThread *jt = Threads::first(); 114 size_t thread_count = 0; 115 while (jt) { 116 thread_count++; 117 EventThreadCPULoad event(UNTIMED); 118 if (JfrThreadCPULoadEvent::update_event(event, jt, cur_wallclock_time, processor_count)) { 119 event.set_starttime(event_time); 120 if (jt != periodic_thread) { 121 // Commit reads the thread id from this thread's trace data, so put it there temporarily 122 periodic_trace_data->set_thread_id(THREAD_TRACE_ID(jt)); 123 } else { 124 periodic_trace_data->set_thread_id(periodic_thread_id); 125 } 126 event.commit(); 127 } 128 jt = jt->next(); 129 } 130 log_trace(jfr)("Measured CPU usage for %d threads in %.3f milliseconds", thread_count, 131 (double)(JfrTraceTime::now() - event_time) / (JfrTraceTime::frequency() / 1000)); 132 // Restore this thread's thread id 133 periodic_trace_data->set_thread_id(periodic_thread_id); 134 } 135 136 void JfrThreadCPULoadEvent::send_event_for_thread(JavaThread* jt) { 137 EventThreadCPULoad event; 138 if (event.should_commit()) { 139 if (update_event(event, jt, get_wallclock_time(), get_processor_count())) { 140 event.commit(); 141 } 142 } 143 }