--- old/src/hotspot/share/runtime/handshake.cpp 2019-11-26 11:55:18.550697351 +0100 +++ new/src/hotspot/share/runtime/handshake.cpp 2019-11-26 11:55:18.286685519 +0100 @@ -32,7 +32,6 @@ #include "runtime/osThread.hpp" #include "runtime/semaphore.inline.hpp" #include "runtime/task.hpp" -#include "runtime/timerTrace.hpp" #include "runtime/thread.hpp" #include "runtime/vmThread.hpp" #include "utilities/formatBuffer.hpp" @@ -86,6 +85,14 @@ fatal("Handshake operation timed out"); } +static void log_handshake_info(jlong start_time_ns, const char* name, int targets, int vmt_executed, const char* extra) { + if (start_time_ns != 0) { + jlong completion_time = os::javaTimeNanos() - start_time_ns; + log_info(handshake)("Handshake \"%s\", Targeted threads: %d, Executed by targeted threads: %d, Total completion time: " JLONG_FORMAT " ns%s", + name, targets, targets - vmt_executed, completion_time, extra); + } +} + class VM_HandshakeOneThread: public VM_Handshake { JavaThread* _target; public: @@ -94,20 +101,25 @@ void doit() { DEBUG_ONLY(_op->check_state();) - TraceTime timer("Finished executing single-target operation (VM_HandshakeOneThread::doit)", TRACETIME_LOG(Info, handshake)); + + jlong start_time_ns = 0; + if (log_is_enabled(Info, handshake)) { + start_time_ns = os::javaTimeNanos(); + } ThreadsListHandle tlh; if (tlh.includes(_target)) { set_handshake(_target); } else { - log_trace(handshake)("JavaThread " INTPTR_FORMAT " is not alive", p2i(_target)); + log_handshake_info(start_time_ns, _op->name(), 0, 0, " (thread dead)"); return; } log_trace(handshake)("JavaThread " INTPTR_FORMAT " signaled, begin attempt to process by VMThtread", p2i(_target)); - jlong start_time = os::elapsed_counter(); + jlong timeout_start_time = os::elapsed_counter(); + bool by_vm_thread = false; do { - if (handshake_has_timed_out(start_time)) { + if (handshake_has_timed_out(timeout_start_time)) { handle_timeout(); } @@ -116,10 +128,11 @@ // locked during certain phases. { MutexLocker ml(Threads_lock); - _target->handshake_process_by_vmthread(); + by_vm_thread = _target->handshake_process_by_vmthread(); } } while (!poll_for_completed_thread()); DEBUG_ONLY(_op->check_state();) + log_handshake_info(start_time_ns, _op->name(), 1, by_vm_thread ? 1 : 0, ""); } VMOp_Type type() const { return VMOp_HandshakeOneThread; } @@ -133,7 +146,12 @@ void doit() { DEBUG_ONLY(_op->check_state();) - TraceTime timer("Finished executing multi-target operation (VM_HandshakeAllThreads::doit)", TRACETIME_LOG(Info, handshake)); + + jlong start_time_ns = 0; + if (log_is_enabled(Info, handshake)) { + start_time_ns = os::javaTimeNanos(); + } + int handshake_executed_by_vm_thread = 0; JavaThreadIteratorWithHandle jtiwh; int number_of_threads_issued = 0; @@ -143,11 +161,11 @@ } if (number_of_threads_issued < 1) { - log_debug(handshake)("No threads to handshake."); + log_handshake_info(start_time_ns, _op->name(), 0, 0, " (no threads)"); return; } - log_debug(handshake)("Threads signaled, begin processing blocked threads by VMThtread"); + log_trace(handshake)("Threads signaled, begin processing blocked threads by VMThtread"); const jlong start_time = os::elapsed_counter(); int number_of_threads_completed = 0; do { @@ -168,7 +186,9 @@ for (JavaThread *thr = jtiwh.next(); thr != NULL; thr = jtiwh.next()) { // A new thread on the ThreadsList will not have an operation, // hence it is skipped in handshake_process_by_vmthread. - thr->handshake_process_by_vmthread(); + if (thr->handshake_process_by_vmthread()) { + handshake_executed_by_vm_thread++; + } } } @@ -180,6 +200,8 @@ } while (number_of_threads_issued > number_of_threads_completed); assert(number_of_threads_issued == number_of_threads_completed, "Must be the same"); DEBUG_ONLY(_op->check_state();) + + log_handshake_info(start_time_ns, _op->name(), number_of_threads_issued, handshake_executed_by_vm_thread, ""); } VMOp_Type type() const { return VMOp_HandshakeAllThreads; } @@ -197,7 +219,7 @@ _hs_op(hs_op), _target_thread(target), _all_threads(false), _executed(false) {} void doit() { - log_trace(handshake)("VMThread executing VM_HandshakeFallbackOperation"); + log_trace(handshake)("VMThread executing VM_HandshakeFallbackOperation, operation: %s", name()); for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { if (_all_threads || t == _target_thread) { if (t == _target_thread) { @@ -213,10 +235,10 @@ }; void HandshakeOperation::do_handshake(JavaThread* thread) { - ResourceMark rm; - FormatBufferResource message("Operation for thread " PTR_FORMAT ", is_vm_thread: %s", - p2i(thread), BOOL_TO_STR(Thread::current()->is_VM_thread())); - TraceTime timer(message, TRACETIME_LOG(Debug, handshake, task)); + jlong start_time_ns = 0; + if (log_is_enabled(Debug, handshake, task)) { + start_time_ns = os::javaTimeNanos(); + } // Only actually execute the operation for non terminated threads. if (!thread->is_terminated()) { @@ -226,6 +248,12 @@ // Use the semaphore to inform the VM thread that we have completed the operation _done.signal(); + + if (start_time_ns != 0) { + jlong completion_time = os::javaTimeNanos() - start_time_ns; + log_debug(handshake, task)("Operation: %s for thread " PTR_FORMAT ", is_vm_thread: %s, completed in " JLONG_FORMAT " ns", + name(), p2i(thread), BOOL_TO_STR(Thread::current()->is_VM_thread()), completion_time); + } } void Handshake::execute(HandshakeOperation* hs_op) { @@ -322,37 +350,41 @@ return false; } -void HandshakeState::process_by_vmthread(JavaThread* target) { +bool HandshakeState::process_by_vmthread(JavaThread* target) { assert(Thread::current()->is_VM_thread(), "should call from vm thread"); // Threads_lock must be held here, but that is assert()ed in // possibly_vmthread_can_process_handshake(). if (!has_operation()) { // JT has already cleared its handshake - return; + return false; } if (!possibly_vmthread_can_process_handshake(target)) { // JT is observed in an unsafe state, it must notice the handshake itself - return; + return false; } // Claim the semaphore if there still an operation to be executed. if (!claim_handshake_for_vmthread()) { - return; + return false; } // If we own the semaphore at this point and while owning the semaphore // can observe a safe state the thread cannot possibly continue without // getting caught by the semaphore. + bool executed = false; if (vmthread_can_process_handshake(target)) { guarantee(!_semaphore.trywait(), "we should already own the semaphore"); log_trace(handshake)("Processing handshake by VMThtread"); _operation->do_handshake(target); // Disarm after VM thread have executed the operation. clear_handshake(target); - // Release the thread + executed = true; } + // Release the thread _semaphore.signal(); + + return executed; } --- old/src/hotspot/share/runtime/handshake.hpp 2019-11-26 11:55:19.722749880 +0100 +++ new/src/hotspot/share/runtime/handshake.hpp 2019-11-26 11:55:19.461738182 +0100 @@ -97,7 +97,7 @@ } } - void process_by_vmthread(JavaThread* target); + bool process_by_vmthread(JavaThread* target); }; #endif // SHARE_RUNTIME_HANDSHAKE_HPP --- old/src/hotspot/share/runtime/thread.hpp 2019-11-26 11:55:20.885802005 +0100 +++ new/src/hotspot/share/runtime/thread.hpp 2019-11-26 11:55:20.620790128 +0100 @@ -1329,8 +1329,8 @@ _handshake.process_by_self(this); } - void handshake_process_by_vmthread() { - _handshake.process_by_vmthread(this); + bool handshake_process_by_vmthread() { + return _handshake.process_by_vmthread(this); } // Suspend/resume support for JavaThread