| /* |
| * Copyright (c) 2012, 2022, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| #include "jfr/jfrEvents.hpp" |
| #include "jfr/recorder/jfrRecorder.hpp" |
| #include "jfr/periodic/sampling/jfrCallTrace.hpp" |
| #include "jfr/periodic/sampling/jfrThreadSampler.hpp" |
| #include "jfr/recorder/checkpoint/types/traceid/jfrTraceIdLoadBarrier.inline.hpp" |
| #include "jfr/recorder/service/jfrOptionSet.hpp" |
| #include "jfr/recorder/stacktrace/jfrStackTraceRepository.hpp" |
| #include "jfr/recorder/storage/jfrBuffer.hpp" |
| #include "jfr/support/jfrThreadLocal.hpp" |
| #include "jfr/utilities/jfrTime.hpp" |
| #include "jfrfiles/jfrEventClasses.hpp" |
| #include "logging/log.hpp" |
| #include "runtime/atomic.hpp" |
| #include "runtime/frame.inline.hpp" |
| #include "runtime/globals.hpp" |
| #include "runtime/javaThread.inline.hpp" |
| #include "runtime/os.hpp" |
| #include "runtime/semaphore.hpp" |
| #include "runtime/stackWatermark.hpp" |
| #include "runtime/suspendedThreadTask.hpp" |
| #include "runtime/threadCrashProtection.hpp" |
| #include "runtime/threadSMR.hpp" |
| #include "utilities/systemMemoryBarrier.hpp" |
| |
| enum JfrSampleType { |
| NO_SAMPLE = 0, |
| JAVA_SAMPLE = 1, |
| NATIVE_SAMPLE = 2 |
| }; |
| |
| static bool thread_state_in_java(JavaThread* thread) { |
| assert(thread != NULL, "invariant"); |
| switch(thread->thread_state()) { |
| case _thread_new: |
| case _thread_uninitialized: |
| case _thread_new_trans: |
| case _thread_in_vm_trans: |
| case _thread_blocked_trans: |
| case _thread_in_native_trans: |
| case _thread_blocked: |
| case _thread_in_vm: |
| case _thread_in_native: |
| case _thread_in_Java_trans: |
| break; |
| case _thread_in_Java: |
| return true; |
| default: |
| ShouldNotReachHere(); |
| break; |
| } |
| return false; |
| } |
| |
| static bool thread_state_in_native(JavaThread* thread) { |
| assert(thread != NULL, "invariant"); |
| switch(thread->thread_state()) { |
| case _thread_new: |
| case _thread_uninitialized: |
| case _thread_new_trans: |
| case _thread_blocked_trans: |
| case _thread_blocked: |
| case _thread_in_vm: |
| case _thread_in_vm_trans: |
| case _thread_in_Java_trans: |
| case _thread_in_Java: |
| case _thread_in_native_trans: |
| break; |
| case _thread_in_native: |
| return true; |
| default: |
| ShouldNotReachHere(); |
| break; |
| } |
| return false; |
| } |
| |
| class JfrThreadSampleClosure { |
| public: |
| JfrThreadSampleClosure(EventExecutionSample* events, EventNativeMethodSample* events_native); |
| ~JfrThreadSampleClosure() {} |
| EventExecutionSample* next_event() { return &_events[_added_java++]; } |
| EventNativeMethodSample* next_event_native() { return &_events_native[_added_native++]; } |
| void commit_events(JfrSampleType type); |
| bool do_sample_thread(JavaThread* thread, JfrStackFrame* frames, u4 max_frames, JfrSampleType type); |
| uint java_entries() { return _added_java; } |
| uint native_entries() { return _added_native; } |
| |
| private: |
| bool sample_thread_in_java(JavaThread* thread, JfrStackFrame* frames, u4 max_frames); |
| bool sample_thread_in_native(JavaThread* thread, JfrStackFrame* frames, u4 max_frames); |
| EventExecutionSample* _events; |
| EventNativeMethodSample* _events_native; |
| Thread* _self; |
| uint _added_java; |
| uint _added_native; |
| }; |
| |
| class OSThreadSampler : public SuspendedThreadTask { |
| public: |
| OSThreadSampler(JavaThread* thread, |
| JfrThreadSampleClosure& closure, |
| JfrStackFrame *frames, |
| u4 max_frames) : SuspendedThreadTask((Thread*)thread), |
| _success(false), |
| _thread_oop(thread->threadObj()), |
| _stacktrace(frames, max_frames), |
| _closure(closure), |
| _suspend_time() {} |
| |
| void take_sample(); |
| void do_task(const SuspendedThreadTaskContext& context); |
| void protected_task(const SuspendedThreadTaskContext& context); |
| bool success() const { return _success; } |
| const JfrStackTrace& stacktrace() const { return _stacktrace; } |
| |
| private: |
| bool _success; |
| oop _thread_oop; |
| JfrStackTrace _stacktrace; |
| JfrThreadSampleClosure& _closure; |
| JfrTicks _suspend_time; |
| }; |
| |
| class OSThreadSamplerCallback : public CrashProtectionCallback { |
| public: |
| OSThreadSamplerCallback(OSThreadSampler& sampler, const SuspendedThreadTaskContext &context) : |
| _sampler(sampler), _context(context) { |
| } |
| virtual void call() { |
| _sampler.protected_task(_context); |
| } |
| private: |
| OSThreadSampler& _sampler; |
| const SuspendedThreadTaskContext& _context; |
| }; |
| |
| void OSThreadSampler::do_task(const SuspendedThreadTaskContext& context) { |
| #ifndef ASSERT |
| guarantee(JfrOptionSet::sample_protection(), "Sample Protection should be on in product builds"); |
| #endif |
| assert(_suspend_time.value() == 0, "already timestamped!"); |
| _suspend_time = JfrTicks::now(); |
| |
| if (JfrOptionSet::sample_protection()) { |
| OSThreadSamplerCallback cb(*this, context); |
| ThreadCrashProtection crash_protection; |
| if (!crash_protection.call(cb)) { |
| log_error(jfr)("Thread method sampler crashed"); |
| } |
| } else { |
| protected_task(context); |
| } |
| } |
| |
| /* |
| * From this method and down the call tree we attempt to protect against crashes |
| * using a signal handler / __try block. Don't take locks, rely on destructors or |
| * leave memory (in case of signal / exception) in an inconsistent state. */ |
| void OSThreadSampler::protected_task(const SuspendedThreadTaskContext& context) { |
| JavaThread* const jt = JavaThread::cast(context.thread()); |
| // Skip sample if we signaled a thread that moved to other state |
| if (!thread_state_in_java(jt)) { |
| return; |
| } |
| JfrGetCallTrace trace(true, jt); |
| frame topframe; |
| if (trace.get_topframe(context.ucontext(), topframe)) { |
| if (_stacktrace.record_async(jt, topframe)) { |
| /* If we managed to get a topframe and a stacktrace, create an event |
| * and put it into our array. We can't call Jfr::_stacktraces.add() |
| * here since it would allocate memory using malloc. Doing so while |
| * the stopped thread is inside malloc would deadlock. */ |
| _success = true; |
| EventExecutionSample *ev = _closure.next_event(); |
| ev->set_starttime(_suspend_time); |
| ev->set_endtime(_suspend_time); // fake to not take an end time |
| ev->set_sampledThread(JfrThreadLocal::thread_id(jt)); |
| ev->set_state(static_cast<u8>(java_lang_Thread::get_thread_status(_thread_oop))); |
| } |
| } |
| } |
| |
| void OSThreadSampler::take_sample() { |
| run(); |
| } |
| |
| class JfrNativeSamplerCallback : public CrashProtectionCallback { |
| public: |
| JfrNativeSamplerCallback(JfrThreadSampleClosure& closure, JavaThread* jt, JfrStackFrame* frames, u4 max_frames) : |
| _closure(closure), _jt(jt), _thread_oop(jt->threadObj()), _stacktrace(frames, max_frames), _success(false) { |
| } |
| virtual void call(); |
| bool success() { return _success; } |
| JfrStackTrace& stacktrace() { return _stacktrace; } |
| |
| private: |
| JfrThreadSampleClosure& _closure; |
| JavaThread* _jt; |
| oop _thread_oop; |
| JfrStackTrace _stacktrace; |
| bool _success; |
| }; |
| |
| static void write_native_event(JfrThreadSampleClosure& closure, JavaThread* jt, oop thread_oop) { |
| EventNativeMethodSample *ev = closure.next_event_native(); |
| ev->set_starttime(JfrTicks::now()); |
| ev->set_sampledThread(JfrThreadLocal::thread_id(jt)); |
| ev->set_state(static_cast<u8>(java_lang_Thread::get_thread_status(thread_oop))); |
| } |
| |
| void JfrNativeSamplerCallback::call() { |
| // When a thread is only attach it will be native without a last java frame |
| if (!_jt->has_last_Java_frame()) { |
| return; |
| } |
| |
| frame topframe = _jt->last_frame(); |
| frame first_java_frame; |
| Method* method = NULL; |
| JfrGetCallTrace gct(false, _jt); |
| if (!gct.find_top_frame(topframe, &method, first_java_frame)) { |
| return; |
| } |
| if (method == NULL) { |
| return; |
| } |
| topframe = first_java_frame; |
| _success = _stacktrace.record_async(_jt, topframe); |
| if (_success) { |
| write_native_event(_closure, _jt, _thread_oop); |
| } |
| } |
| |
| bool JfrThreadSampleClosure::sample_thread_in_java(JavaThread* thread, JfrStackFrame* frames, u4 max_frames) { |
| // Process the oops in the thread head before calling into code that wants to |
| // stack walk over Loom continuations. The stack walking code will otherwise |
| // skip frames in stack chunks on the Java heap. |
| StackWatermarkSet::start_processing(thread, StackWatermarkKind::gc); |
| |
| OSThreadSampler sampler(thread, *this, frames, max_frames); |
| sampler.take_sample(); |
| /* We don't want to allocate any memory using malloc/etc while the thread |
| * is stopped, so everything is stored in stack allocated memory until this |
| * point where the thread has been resumed again, if the sampling was a success |
| * we need to store the stacktrace in the stacktrace repository and update |
| * the event with the id that was returned. */ |
| if (!sampler.success()) { |
| return false; |
| } |
| EventExecutionSample *event = &_events[_added_java - 1]; |
| traceid id = JfrStackTraceRepository::add(sampler.stacktrace()); |
| assert(id != 0, "Stacktrace id should not be 0"); |
| event->set_stackTrace(id); |
| return true; |
| } |
| |
| bool JfrThreadSampleClosure::sample_thread_in_native(JavaThread* thread, JfrStackFrame* frames, u4 max_frames) { |
| // Process the oops in the thread head before calling into code that wants to |
| // stack walk over Loom continuations. The stack walking code will otherwise |
| // skip frames in stack chunks on the Java heap. |
| StackWatermarkSet::start_processing(thread, StackWatermarkKind::gc); |
| |
| JfrNativeSamplerCallback cb(*this, thread, frames, max_frames); |
| if (JfrOptionSet::sample_protection()) { |
| ThreadCrashProtection crash_protection; |
| if (!crash_protection.call(cb)) { |
| log_error(jfr)("Thread method sampler crashed for native"); |
| } |
| } else { |
| cb.call(); |
| } |
| if (!cb.success()) { |
| return false; |
| } |
| EventNativeMethodSample *event = &_events_native[_added_native - 1]; |
| traceid id = JfrStackTraceRepository::add(cb.stacktrace()); |
| assert(id != 0, "Stacktrace id should not be 0"); |
| event->set_stackTrace(id); |
| return true; |
| } |
| |
| static const uint MAX_NR_OF_JAVA_SAMPLES = 5; |
| static const uint MAX_NR_OF_NATIVE_SAMPLES = 1; |
| |
| void JfrThreadSampleClosure::commit_events(JfrSampleType type) { |
| if (JAVA_SAMPLE == type) { |
| assert(_added_java > 0 && _added_java <= MAX_NR_OF_JAVA_SAMPLES, "invariant"); |
| if (EventExecutionSample::is_enabled()) { |
| for (uint i = 0; i < _added_java; ++i) { |
| _events[i].commit(); |
| } |
| } |
| } else { |
| assert(NATIVE_SAMPLE == type, "invariant"); |
| assert(_added_native > 0 && _added_native <= MAX_NR_OF_NATIVE_SAMPLES, "invariant"); |
| if (EventNativeMethodSample::is_enabled()) { |
| for (uint i = 0; i < _added_native; ++i) { |
| _events_native[i].commit(); |
| } |
| } |
| } |
| } |
| |
| JfrThreadSampleClosure::JfrThreadSampleClosure(EventExecutionSample* events, EventNativeMethodSample* events_native) : |
| _events(events), |
| _events_native(events_native), |
| _self(Thread::current()), |
| _added_java(0), |
| _added_native(0) { |
| } |
| |
| class JfrThreadSampler : public NonJavaThread { |
| friend class JfrThreadSampling; |
| private: |
| Semaphore _sample; |
| Thread* _sampler_thread; |
| JfrStackFrame* const _frames; |
| JavaThread* _last_thread_java; |
| JavaThread* _last_thread_native; |
| int64_t _java_period_millis; |
| int64_t _native_period_millis; |
| const size_t _min_size; // for enqueue buffer monitoring |
| int _cur_index; |
| const u4 _max_frames; |
| volatile bool _disenrolled; |
| |
| const JfrBuffer* get_enqueue_buffer(); |
| const JfrBuffer* renew_if_full(const JfrBuffer* enqueue_buffer); |
| |
| JavaThread* next_thread(ThreadsList* t_list, JavaThread* first_sampled, JavaThread* current); |
| void task_stacktrace(JfrSampleType type, JavaThread** last_thread); |
| JfrThreadSampler(int64_t java_period_millis, int64_t native_period_millis, u4 max_frames); |
| ~JfrThreadSampler(); |
| |
| void start_thread(); |
| |
| void enroll(); |
| void disenroll(); |
| void set_java_period(int64_t period_millis); |
| void set_native_period(int64_t period_millis); |
| protected: |
| virtual void post_run(); |
| public: |
| virtual const char* name() const { return "JFR Thread Sampler"; } |
| virtual const char* type_name() const { return "JfrThreadSampler"; } |
| bool is_JfrSampler_thread() const { return true; } |
| void run(); |
| static Monitor* transition_block() { return JfrThreadSampler_lock; } |
| static void on_javathread_suspend(JavaThread* thread); |
| int64_t get_java_period() const { return Atomic::load(&_java_period_millis); }; |
| int64_t get_native_period() const { return Atomic::load(&_native_period_millis); }; |
| }; |
| |
| static void clear_transition_block(JavaThread* jt) { |
| assert(Threads_lock->owned_by_self(), "Holding the thread table lock."); |
| jt->clear_trace_flag(); |
| JfrThreadLocal* const tl = jt->jfr_thread_local(); |
| MutexLocker ml(JfrThreadSampler::transition_block(), Mutex::_no_safepoint_check_flag); |
| if (tl->is_trace_block()) { |
| JfrThreadSampler::transition_block()->notify(); |
| } |
| } |
| |
| static bool is_excluded(JavaThread* thread) { |
| assert(thread != NULL, "invariant"); |
| return thread->is_hidden_from_external_view() || thread->in_deopt_handler() || thread->jfr_thread_local()->is_excluded(); |
| } |
| |
| bool JfrThreadSampleClosure::do_sample_thread(JavaThread* thread, JfrStackFrame* frames, u4 max_frames, JfrSampleType type) { |
| assert(Threads_lock->owned_by_self(), "Holding the thread table lock."); |
| if (is_excluded(thread)) { |
| return false; |
| } |
| |
| bool ret = false; |
| thread->set_trace_flag(); // Provides StoreLoad, needed to keep read of thread state from floating up. |
| if (UseSystemMemoryBarrier) { |
| SystemMemoryBarrier::emit(); |
| } |
| if (JAVA_SAMPLE == type) { |
| if (thread_state_in_java(thread)) { |
| ret = sample_thread_in_java(thread, frames, max_frames); |
| } |
| } else { |
| assert(NATIVE_SAMPLE == type, "invariant"); |
| if (thread_state_in_native(thread)) { |
| ret = sample_thread_in_native(thread, frames, max_frames); |
| } |
| } |
| clear_transition_block(thread); |
| return ret; |
| } |
| |
| JfrThreadSampler::JfrThreadSampler(int64_t java_period_millis, int64_t native_period_millis, u4 max_frames) : |
| _sample(), |
| _sampler_thread(NULL), |
| _frames(JfrCHeapObj::new_array<JfrStackFrame>(max_frames)), |
| _last_thread_java(NULL), |
| _last_thread_native(NULL), |
| _java_period_millis(java_period_millis), |
| _native_period_millis(native_period_millis), |
| _min_size(max_frames * 2 * wordSize), // each frame tags at most 2 words, min size is a full stacktrace |
| _cur_index(-1), |
| _max_frames(max_frames), |
| _disenrolled(true) { |
| assert(_java_period_millis >= 0, "invariant"); |
| assert(_native_period_millis >= 0, "invariant"); |
| } |
| |
| JfrThreadSampler::~JfrThreadSampler() { |
| JfrCHeapObj::free(_frames, sizeof(JfrStackFrame) * _max_frames); |
| } |
| |
| void JfrThreadSampler::set_java_period(int64_t period_millis) { |
| assert(period_millis >= 0, "invariant"); |
| Atomic::store(&_java_period_millis, period_millis); |
| } |
| |
| void JfrThreadSampler::set_native_period(int64_t period_millis) { |
| assert(period_millis >= 0, "invariant"); |
| Atomic::store(&_native_period_millis, period_millis); |
| } |
| |
| static inline bool is_released(JavaThread* jt) { |
| return !jt->is_trace_suspend(); |
| } |
| |
| void JfrThreadSampler::on_javathread_suspend(JavaThread* thread) { |
| if (is_released(thread)) { |
| return; |
| } |
| JfrThreadLocal* const tl = thread->jfr_thread_local(); |
| MonitorLocker ml(transition_block(), Mutex::_no_safepoint_check_flag); |
| tl->set_trace_block(); |
| while (!is_released(thread)) { |
| ml.wait(); |
| } |
| tl->clear_trace_block(); |
| } |
| |
| JavaThread* JfrThreadSampler::next_thread(ThreadsList* t_list, JavaThread* first_sampled, JavaThread* current) { |
| assert(t_list != NULL, "invariant"); |
| assert(Threads_lock->owned_by_self(), "Holding the thread table lock."); |
| assert(_cur_index >= -1 && (uint)_cur_index + 1 <= t_list->length(), "invariant"); |
| assert((current == NULL && -1 == _cur_index) || (t_list->find_index_of_JavaThread(current) == _cur_index), "invariant"); |
| if ((uint)_cur_index + 1 == t_list->length()) { |
| // wrap |
| _cur_index = 0; |
| } else { |
| _cur_index++; |
| } |
| assert(_cur_index >= 0 && (uint)_cur_index < t_list->length(), "invariant"); |
| JavaThread* const next = t_list->thread_at(_cur_index); |
| return next != first_sampled ? next : NULL; |
| } |
| |
| void JfrThreadSampler::start_thread() { |
| if (os::create_thread(this, os::os_thread)) { |
| os::start_thread(this); |
| } else { |
| log_error(jfr)("Failed to create thread for thread sampling"); |
| } |
| } |
| |
| void JfrThreadSampler::enroll() { |
| if (_disenrolled) { |
| log_trace(jfr)("Enrolling thread sampler"); |
| _sample.signal(); |
| _disenrolled = false; |
| } |
| } |
| |
| void JfrThreadSampler::disenroll() { |
| if (!_disenrolled) { |
| _sample.wait(); |
| _disenrolled = true; |
| log_trace(jfr)("Disenrolling thread sampler"); |
| } |
| } |
| |
| static int64_t get_monotonic_ms() { |
| return os::javaTimeNanos() / 1000000; |
| } |
| |
| void JfrThreadSampler::run() { |
| assert(_sampler_thread == NULL, "invariant"); |
| |
| _sampler_thread = this; |
| |
| int64_t last_java_ms = get_monotonic_ms(); |
| int64_t last_native_ms = last_java_ms; |
| while (true) { |
| if (!_sample.trywait()) { |
| // disenrolled |
| _sample.wait(); |
| last_java_ms = get_monotonic_ms(); |
| last_native_ms = last_java_ms; |
| } |
| _sample.signal(); |
| |
| int64_t java_period_millis = get_java_period(); |
| java_period_millis = java_period_millis == 0 ? max_jlong : MAX2<int64_t>(java_period_millis, 1); |
| int64_t native_period_millis = get_native_period(); |
| native_period_millis = native_period_millis == 0 ? max_jlong : MAX2<int64_t>(native_period_millis, 1); |
| |
| // If both periods are max_jlong, it implies the sampler is in the process of |
| // disenrolling. Loop back for graceful disenroll by means of the semaphore. |
| if (java_period_millis == max_jlong && native_period_millis == max_jlong) { |
| continue; |
| } |
| |
| const int64_t now_ms = get_monotonic_ms(); |
| |
| /* |
| * Let I be java_period or native_period. |
| * Let L be last_java_ms or last_native_ms. |
| * Let N be now_ms. |
| * |
| * Interval, I, might be max_jlong so the addition |
| * could potentially overflow without parenthesis (UB). Also note that |
| * L - N < 0. Avoid UB, by adding parenthesis. |
| */ |
| const int64_t next_j = java_period_millis + (last_java_ms - now_ms); |
| const int64_t next_n = native_period_millis + (last_native_ms - now_ms); |
| |
| const int64_t sleep_to_next = MIN2<int64_t>(next_j, next_n); |
| |
| if (sleep_to_next > 0) { |
| os::naked_sleep(sleep_to_next); |
| } |
| |
| if ((next_j - sleep_to_next) <= 0) { |
| task_stacktrace(JAVA_SAMPLE, &_last_thread_java); |
| last_java_ms = get_monotonic_ms(); |
| } |
| if ((next_n - sleep_to_next) <= 0) { |
| task_stacktrace(NATIVE_SAMPLE, &_last_thread_native); |
| last_native_ms = get_monotonic_ms(); |
| } |
| } |
| } |
| |
| void JfrThreadSampler::post_run() { |
| this->NonJavaThread::post_run(); |
| delete this; |
| } |
| |
| const JfrBuffer* JfrThreadSampler::get_enqueue_buffer() { |
| const JfrBuffer* buffer = JfrTraceIdLoadBarrier::get_sampler_enqueue_buffer(this); |
| return buffer != nullptr ? renew_if_full(buffer) : JfrTraceIdLoadBarrier::renew_sampler_enqueue_buffer(this); |
| } |
| |
| const JfrBuffer* JfrThreadSampler::renew_if_full(const JfrBuffer* enqueue_buffer) { |
| assert(enqueue_buffer != nullptr, "invariant"); |
| return enqueue_buffer->free_size() < _min_size ? JfrTraceIdLoadBarrier::renew_sampler_enqueue_buffer(this) : enqueue_buffer; |
| } |
| |
| void JfrThreadSampler::task_stacktrace(JfrSampleType type, JavaThread** last_thread) { |
| ResourceMark rm; |
| EventExecutionSample samples[MAX_NR_OF_JAVA_SAMPLES]; |
| EventNativeMethodSample samples_native[MAX_NR_OF_NATIVE_SAMPLES]; |
| JfrThreadSampleClosure sample_task(samples, samples_native); |
| |
| const uint sample_limit = JAVA_SAMPLE == type ? MAX_NR_OF_JAVA_SAMPLES : MAX_NR_OF_NATIVE_SAMPLES; |
| uint num_samples = 0; |
| JavaThread* start = NULL; |
| { |
| elapsedTimer sample_time; |
| sample_time.start(); |
| { |
| MutexLocker tlock(Threads_lock); |
| ThreadsListHandle tlh; |
| // Resolve a sample session relative start position index into the thread list array. |
| // In cases where the last sampled thread is NULL or not-NULL but stale, find_index() returns -1. |
| _cur_index = tlh.list()->find_index_of_JavaThread(*last_thread); |
| JavaThread* current = _cur_index != -1 ? *last_thread : NULL; |
| |
| // Explicitly monitor the available space of the thread-local buffer used by the load barrier |
| // for enqueuing klasses as part of tagging methods. We do this because if space becomes sparse, |
| // we cannot rely on the implicit allocation of a new buffer as part of the regular tag mechanism. |
| // If the free list is empty, a malloc could result, and the problem with that is that the thread |
| // we have suspended could be the holder of the malloc lock. Instead, the buffer is pre-emptively |
| // renewed before thread suspension. |
| const JfrBuffer* enqueue_buffer = get_enqueue_buffer(); |
| assert(enqueue_buffer != nullptr, "invariant"); |
| |
| while (num_samples < sample_limit) { |
| current = next_thread(tlh.list(), start, current); |
| if (current == NULL) { |
| break; |
| } |
| if (start == NULL) { |
| start = current; // remember the thread where we started to attempt sampling |
| } |
| if (current->is_Compiler_thread()) { |
| continue; |
| } |
| assert(enqueue_buffer->free_size() >= _min_size, "invariant"); |
| if (sample_task.do_sample_thread(current, _frames, _max_frames, type)) { |
| num_samples++; |
| } |
| enqueue_buffer = renew_if_full(enqueue_buffer); |
| } |
| *last_thread = current; // remember the thread we last attempted to sample |
| } |
| sample_time.stop(); |
| log_trace(jfr)("JFR thread sampling done in %3.7f secs with %d java %d native samples", |
| sample_time.seconds(), sample_task.java_entries(), sample_task.native_entries()); |
| } |
| if (num_samples > 0) { |
| sample_task.commit_events(type); |
| } |
| } |
| |
| static JfrThreadSampling* _instance = NULL; |
| |
| JfrThreadSampling& JfrThreadSampling::instance() { |
| return *_instance; |
| } |
| |
| JfrThreadSampling* JfrThreadSampling::create() { |
| assert(_instance == NULL, "invariant"); |
| _instance = new JfrThreadSampling(); |
| return _instance; |
| } |
| |
| void JfrThreadSampling::destroy() { |
| if (_instance != NULL) { |
| delete _instance; |
| _instance = NULL; |
| } |
| } |
| |
| JfrThreadSampling::JfrThreadSampling() : _sampler(NULL) {} |
| |
| JfrThreadSampling::~JfrThreadSampling() { |
| if (_sampler != NULL) { |
| _sampler->disenroll(); |
| } |
| } |
| |
| #ifdef ASSERT |
| void assert_periods(const JfrThreadSampler* sampler, int64_t java_period_millis, int64_t native_period_millis) { |
| assert(sampler != nullptr, "invariant"); |
| assert(sampler->get_java_period() == java_period_millis, "invariant"); |
| assert(sampler->get_native_period() == native_period_millis, "invariant"); |
| } |
| #endif |
| |
| static void log(int64_t java_period_millis, int64_t native_period_millis) { |
| log_trace(jfr)("Updated thread sampler for java: " INT64_FORMAT " ms, native " INT64_FORMAT " ms", java_period_millis, native_period_millis); |
| } |
| |
| void JfrThreadSampling::create_sampler(int64_t java_period_millis, int64_t native_period_millis) { |
| assert(_sampler == nullptr, "invariant"); |
| log_trace(jfr)("Creating thread sampler for java:" INT64_FORMAT " ms, native " INT64_FORMAT " ms", java_period_millis, native_period_millis); |
| _sampler = new JfrThreadSampler(java_period_millis, native_period_millis, JfrOptionSet::stackdepth()); |
| _sampler->start_thread(); |
| _sampler->enroll(); |
| } |
| |
| void JfrThreadSampling::update_run_state(int64_t java_period_millis, int64_t native_period_millis) { |
| if (java_period_millis > 0 || native_period_millis > 0) { |
| if (_sampler == nullptr) { |
| create_sampler(java_period_millis, native_period_millis); |
| } else { |
| _sampler->enroll(); |
| } |
| DEBUG_ONLY(assert_periods(_sampler, java_period_millis, native_period_millis);) |
| log(java_period_millis, native_period_millis); |
| return; |
| } |
| if (_sampler != nullptr) { |
| DEBUG_ONLY(assert_periods(_sampler, java_period_millis, native_period_millis);) |
| _sampler->disenroll(); |
| } |
| } |
| |
| void JfrThreadSampling::set_sampling_period(bool is_java_period, int64_t period_millis) { |
| int64_t java_period_millis = 0; |
| int64_t native_period_millis = 0; |
| if (is_java_period) { |
| java_period_millis = period_millis; |
| if (_sampler != nullptr) { |
| _sampler->set_java_period(java_period_millis); |
| native_period_millis = _sampler->get_native_period(); |
| } |
| } else { |
| native_period_millis = period_millis; |
| if (_sampler != nullptr) { |
| _sampler->set_native_period(native_period_millis); |
| java_period_millis = _sampler->get_java_period(); |
| } |
| } |
| update_run_state(java_period_millis, native_period_millis); |
| } |
| |
| void JfrThreadSampling::set_java_sample_period(int64_t period_millis) { |
| assert(period_millis >= 0, "invariant"); |
| if (_instance == NULL && 0 == period_millis) { |
| return; |
| } |
| instance().set_sampling_period(true, period_millis); |
| } |
| |
| void JfrThreadSampling::set_native_sample_period(int64_t period_millis) { |
| assert(period_millis >= 0, "invariant"); |
| if (_instance == NULL && 0 == period_millis) { |
| return; |
| } |
| instance().set_sampling_period(false, period_millis); |
| } |
| |
| void JfrThreadSampling::on_javathread_suspend(JavaThread* thread) { |
| JfrThreadSampler::on_javathread_suspend(thread); |
| } |