--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/compiler/compilationPolicy.cpp Wed Oct 09 12:43:32 2019 -0700
@@ -0,0 +1,506 @@
+/*
+ * Copyright (c) 2000, 2019, 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 "classfile/classLoaderDataGraph.inline.hpp"
+#include "code/compiledIC.hpp"
+#include "code/nmethod.hpp"
+#include "code/scopeDesc.hpp"
+#include "compiler/compilationPolicy.hpp"
+#include "compiler/tieredThresholdPolicy.hpp"
+#include "interpreter/interpreter.hpp"
+#include "memory/resourceArea.hpp"
+#include "oops/methodData.hpp"
+#include "oops/method.inline.hpp"
+#include "oops/oop.inline.hpp"
+#include "prims/nativeLookup.hpp"
+#include "runtime/frame.hpp"
+#include "runtime/handles.inline.hpp"
+#include "runtime/stubRoutines.hpp"
+#include "runtime/thread.hpp"
+#include "runtime/vframe.hpp"
+#include "runtime/vmOperations.hpp"
+#include "utilities/events.hpp"
+#include "utilities/globalDefinitions.hpp"
+
+#ifdef COMPILER1
+#include "c1/c1_Compiler.hpp"
+#endif
+#ifdef COMPILER2
+#include "opto/c2compiler.hpp"
+#endif
+
+CompilationPolicy* CompilationPolicy::_policy;
+
+// Determine compilation policy based on command line argument
+void compilationPolicy_init() {
+ #ifdef TIERED
+ if (TieredCompilation) {
+ CompilationPolicy::set_policy(new TieredThresholdPolicy());
+ } else {
+ CompilationPolicy::set_policy(new SimpleCompPolicy());
+ }
+ #else
+ CompilationPolicy::set_policy(new SimpleCompPolicy());
+ #endif
+
+ CompilationPolicy::policy()->initialize();
+}
+
+// Returns true if m must be compiled before executing it
+// This is intended to force compiles for methods (usually for
+// debugging) that would otherwise be interpreted for some reason.
+bool CompilationPolicy::must_be_compiled(const methodHandle& m, int comp_level) {
+ // Don't allow Xcomp to cause compiles in replay mode
+ if (ReplayCompiles) return false;
+
+ if (m->has_compiled_code()) return false; // already compiled
+ if (!can_be_compiled(m, comp_level)) return false;
+
+ return !UseInterpreter || // must compile all methods
+ (UseCompiler && AlwaysCompileLoopMethods && m->has_loops() && CompileBroker::should_compile_new_jobs()); // eagerly compile loop methods
+}
+
+void CompilationPolicy::compile_if_required(const methodHandle& selected_method, TRAPS) {
+ if (must_be_compiled(selected_method)) {
+ // This path is unusual, mostly used by the '-Xcomp' stress test mode.
+
+ // Note: with several active threads, the must_be_compiled may be true
+ // while can_be_compiled is false; remove assert
+ // assert(CompilationPolicy::can_be_compiled(selected_method), "cannot compile");
+ if (!THREAD->can_call_java() || THREAD->is_Compiler_thread()) {
+ // don't force compilation, resolve was on behalf of compiler
+ return;
+ }
+ if (selected_method->method_holder()->is_not_initialized()) {
+ // 'is_not_initialized' means not only '!is_initialized', but also that
+ // initialization has not been started yet ('!being_initialized')
+ // Do not force compilation of methods in uninitialized classes.
+ // Note that doing this would throw an assert later,
+ // in CompileBroker::compile_method.
+ // We sometimes use the link resolver to do reflective lookups
+ // even before classes are initialized.
+ return;
+ }
+ CompileBroker::compile_method(selected_method, InvocationEntryBci,
+ CompilationPolicy::policy()->initial_compile_level(),
+ methodHandle(), 0, CompileTask::Reason_MustBeCompiled, CHECK);
+ }
+}
+
+// Returns true if m is allowed to be compiled
+bool CompilationPolicy::can_be_compiled(const methodHandle& m, int comp_level) {
+ // allow any levels for WhiteBox
+ assert(WhiteBoxAPI || comp_level == CompLevel_all || is_compile(comp_level), "illegal compilation level");
+
+ if (m->is_abstract()) return false;
+ if (DontCompileHugeMethods && m->code_size() > HugeMethodLimit) return false;
+
+ // Math intrinsics should never be compiled as this can lead to
+ // monotonicity problems because the interpreter will prefer the
+ // compiled code to the intrinsic version. This can't happen in
+ // production because the invocation counter can't be incremented
+ // but we shouldn't expose the system to this problem in testing
+ // modes.
+ if (!AbstractInterpreter::can_be_compiled(m)) {
+ return false;
+ }
+ if (comp_level == CompLevel_all) {
+ if (TieredCompilation) {
+ // enough to be compilable at any level for tiered
+ return !m->is_not_compilable(CompLevel_simple) || !m->is_not_compilable(CompLevel_full_optimization);
+ } else {
+ // must be compilable at available level for non-tiered
+ return !m->is_not_compilable(CompLevel_highest_tier);
+ }
+ } else if (is_compile(comp_level)) {
+ return !m->is_not_compilable(comp_level);
+ }
+ return false;
+}
+
+// Returns true if m is allowed to be osr compiled
+bool CompilationPolicy::can_be_osr_compiled(const methodHandle& m, int comp_level) {
+ bool result = false;
+ if (comp_level == CompLevel_all) {
+ if (TieredCompilation) {
+ // enough to be osr compilable at any level for tiered
+ result = !m->is_not_osr_compilable(CompLevel_simple) || !m->is_not_osr_compilable(CompLevel_full_optimization);
+ } else {
+ // must be osr compilable at available level for non-tiered
+ result = !m->is_not_osr_compilable(CompLevel_highest_tier);
+ }
+ } else if (is_compile(comp_level)) {
+ result = !m->is_not_osr_compilable(comp_level);
+ }
+ return (result && can_be_compiled(m, comp_level));
+}
+
+bool CompilationPolicy::is_compilation_enabled() {
+ // NOTE: CompileBroker::should_compile_new_jobs() checks for UseCompiler
+ return CompileBroker::should_compile_new_jobs();
+}
+
+CompileTask* CompilationPolicy::select_task_helper(CompileQueue* compile_queue) {
+ // Remove unloaded methods from the queue
+ for (CompileTask* task = compile_queue->first(); task != NULL; ) {
+ CompileTask* next = task->next();
+ if (task->is_unloaded()) {
+ compile_queue->remove_and_mark_stale(task);
+ }
+ task = next;
+ }
+#if INCLUDE_JVMCI
+ if (UseJVMCICompiler && !BackgroundCompilation) {
+ /*
+ * In blocking compilation mode, the CompileBroker will make
+ * compilations submitted by a JVMCI compiler thread non-blocking. These
+ * compilations should be scheduled after all blocking compilations
+ * to service non-compiler related compilations sooner and reduce the
+ * chance of such compilations timing out.
+ */
+ for (CompileTask* task = compile_queue->first(); task != NULL; task = task->next()) {
+ if (task->is_blocking()) {
+ return task;
+ }
+ }
+ }
+#endif
+ return compile_queue->first();
+}
+
+#ifndef PRODUCT
+void SimpleCompPolicy::trace_osr_completion(nmethod* osr_nm) {
+ if (TraceOnStackReplacement) {
+ if (osr_nm == NULL) tty->print_cr("compilation failed");
+ else tty->print_cr("nmethod " INTPTR_FORMAT, p2i(osr_nm));
+ }
+}
+#endif // !PRODUCT
+
+void SimpleCompPolicy::initialize() {
+ // Setup the compiler thread numbers
+ if (CICompilerCountPerCPU) {
+ // Example: if CICompilerCountPerCPU is true, then we get
+ // max(log2(8)-1,1) = 2 compiler threads on an 8-way machine.
+ // May help big-app startup time.
+ _compiler_count = MAX2(log2_int(os::active_processor_count())-1,1);
+ // Make sure there is enough space in the code cache to hold all the compiler buffers
+ size_t buffer_size = 1;
+#ifdef COMPILER1
+ buffer_size = is_client_compilation_mode_vm() ? Compiler::code_buffer_size() : buffer_size;
+#endif
+#ifdef COMPILER2
+ buffer_size = is_server_compilation_mode_vm() ? C2Compiler::initial_code_buffer_size() : buffer_size;
+#endif
+ int max_count = (ReservedCodeCacheSize - (CodeCacheMinimumUseSpace DEBUG_ONLY(* 3))) / (int)buffer_size;
+ if (_compiler_count > max_count) {
+ // Lower the compiler count such that all buffers fit into the code cache
+ _compiler_count = MAX2(max_count, 1);
+ }
+ FLAG_SET_ERGO(CICompilerCount, _compiler_count);
+ } else {
+ _compiler_count = CICompilerCount;
+ }
+}
+
+// Note: this policy is used ONLY if TieredCompilation is off.
+// compiler_count() behaves the following way:
+// - with TIERED build (with both COMPILER1 and COMPILER2 defined) it should return
+// zero for the c1 compilation levels in server compilation mode runs
+// and c2 compilation levels in client compilation mode runs.
+// - with COMPILER2 not defined it should return zero for c2 compilation levels.
+// - with COMPILER1 not defined it should return zero for c1 compilation levels.
+// - if neither is defined - always return zero.
+int SimpleCompPolicy::compiler_count(CompLevel comp_level) {
+ assert(!TieredCompilation, "This policy should not be used with TieredCompilation");
+ if (COMPILER2_PRESENT(is_server_compilation_mode_vm() && is_c2_compile(comp_level) ||)
+ is_client_compilation_mode_vm() && is_c1_compile(comp_level)) {
+ return _compiler_count;
+ }
+ return 0;
+}
+
+void SimpleCompPolicy::reset_counter_for_invocation_event(const methodHandle& m) {
+ // Make sure invocation and backedge counter doesn't overflow again right away
+ // as would be the case for native methods.
+
+ // BUT also make sure the method doesn't look like it was never executed.
+ // Set carry bit and reduce counter's value to min(count, CompileThreshold/2).
+ MethodCounters* mcs = m->method_counters();
+ assert(mcs != NULL, "MethodCounters cannot be NULL for profiling");
+ mcs->invocation_counter()->set_carry();
+ mcs->backedge_counter()->set_carry();
+
+ assert(!m->was_never_executed(), "don't reset to 0 -- could be mistaken for never-executed");
+}
+
+void SimpleCompPolicy::reset_counter_for_back_branch_event(const methodHandle& m) {
+ // Delay next back-branch event but pump up invocation counter to trigger
+ // whole method compilation.
+ MethodCounters* mcs = m->method_counters();
+ assert(mcs != NULL, "MethodCounters cannot be NULL for profiling");
+ InvocationCounter* i = mcs->invocation_counter();
+ InvocationCounter* b = mcs->backedge_counter();
+
+ // Don't set invocation_counter's value too low otherwise the method will
+ // look like immature (ic < ~5300) which prevents the inlining based on
+ // the type profiling.
+ i->set(i->state(), CompileThreshold);
+ // Don't reset counter too low - it is used to check if OSR method is ready.
+ b->set(b->state(), CompileThreshold / 2);
+}
+
+//
+// CounterDecay
+//
+// Iterates through invocation counters and decrements them. This
+// is done at each safepoint.
+//
+class CounterDecay : public AllStatic {
+ static jlong _last_timestamp;
+ static void do_method(Method* m) {
+ MethodCounters* mcs = m->method_counters();
+ if (mcs != NULL) {
+ mcs->invocation_counter()->decay();
+ }
+ }
+public:
+ static void decay();
+ static bool is_decay_needed() {
+ return (os::javaTimeMillis() - _last_timestamp) > CounterDecayMinIntervalLength;
+ }
+};
+
+jlong CounterDecay::_last_timestamp = 0;
+
+void CounterDecay::decay() {
+ _last_timestamp = os::javaTimeMillis();
+
+ // This operation is going to be performed only at the end of a safepoint
+ // and hence GC's will not be going on, all Java mutators are suspended
+ // at this point and hence SystemDictionary_lock is also not needed.
+ assert(SafepointSynchronize::is_at_safepoint(), "can only be executed at a safepoint");
+ size_t nclasses = ClassLoaderDataGraph::num_instance_classes();
+ size_t classes_per_tick = nclasses * (CounterDecayMinIntervalLength * 1e-3 /
+ CounterHalfLifeTime);
+ for (size_t i = 0; i < classes_per_tick; i++) {
+ InstanceKlass* k = ClassLoaderDataGraph::try_get_next_class();
+ if (k != NULL) {
+ k->methods_do(do_method);
+ }
+ }
+}
+
+// Called at the end of the safepoint
+void SimpleCompPolicy::do_safepoint_work() {
+ if(UseCounterDecay && CounterDecay::is_decay_needed()) {
+ CounterDecay::decay();
+ }
+}
+
+void SimpleCompPolicy::reprofile(ScopeDesc* trap_scope, bool is_osr) {
+ ScopeDesc* sd = trap_scope;
+ MethodCounters* mcs;
+ InvocationCounter* c;
+ for (; !sd->is_top(); sd = sd->sender()) {
+ mcs = sd->method()->method_counters();
+ if (mcs != NULL) {
+ // Reset ICs of inlined methods, since they can trigger compilations also.
+ mcs->invocation_counter()->reset();
+ }
+ }
+ mcs = sd->method()->method_counters();
+ if (mcs != NULL) {
+ c = mcs->invocation_counter();
+ if (is_osr) {
+ // It was an OSR method, so bump the count higher.
+ c->set(c->state(), CompileThreshold);
+ } else {
+ c->reset();
+ }
+ mcs->backedge_counter()->reset();
+ }
+}
+
+// This method can be called by any component of the runtime to notify the policy
+// that it's recommended to delay the compilation of this method.
+void SimpleCompPolicy::delay_compilation(Method* method) {
+ MethodCounters* mcs = method->method_counters();
+ if (mcs != NULL) {
+ mcs->invocation_counter()->decay();
+ mcs->backedge_counter()->decay();
+ }
+}
+
+void SimpleCompPolicy::disable_compilation(Method* method) {
+ MethodCounters* mcs = method->method_counters();
+ if (mcs != NULL) {
+ mcs->invocation_counter()->set_state(InvocationCounter::wait_for_nothing);
+ mcs->backedge_counter()->set_state(InvocationCounter::wait_for_nothing);
+ }
+}
+
+CompileTask* SimpleCompPolicy::select_task(CompileQueue* compile_queue) {
+ return select_task_helper(compile_queue);
+}
+
+bool SimpleCompPolicy::is_mature(Method* method) {
+ MethodData* mdo = method->method_data();
+ assert(mdo != NULL, "Should be");
+ uint current = mdo->mileage_of(method);
+ uint initial = mdo->creation_mileage();
+ if (current < initial)
+ return true; // some sort of overflow
+ uint target;
+ if (ProfileMaturityPercentage <= 0)
+ target = (uint) -ProfileMaturityPercentage; // absolute value
+ else
+ target = (uint)( (ProfileMaturityPercentage * CompileThreshold) / 100 );
+ return (current >= initial + target);
+}
+
+nmethod* SimpleCompPolicy::event(const methodHandle& method, const methodHandle& inlinee, int branch_bci,
+ int bci, CompLevel comp_level, CompiledMethod* nm, JavaThread* thread) {
+ assert(comp_level == CompLevel_none, "This should be only called from the interpreter");
+ NOT_PRODUCT(trace_frequency_counter_overflow(method, branch_bci, bci));
+ if (JvmtiExport::can_post_interpreter_events() && thread->is_interp_only_mode()) {
+ // If certain JVMTI events (e.g. frame pop event) are requested then the
+ // thread is forced to remain in interpreted code. This is
+ // implemented partly by a check in the run_compiled_code
+ // section of the interpreter whether we should skip running
+ // compiled code, and partly by skipping OSR compiles for
+ // interpreted-only threads.
+ if (bci != InvocationEntryBci) {
+ reset_counter_for_back_branch_event(method);
+ return NULL;
+ }
+ }
+ if (ReplayCompiles) {
+ // Don't trigger other compiles in testing mode
+ if (bci == InvocationEntryBci) {
+ reset_counter_for_invocation_event(method);
+ } else {
+ reset_counter_for_back_branch_event(method);
+ }
+ return NULL;
+ }
+
+ if (bci == InvocationEntryBci) {
+ // when code cache is full, compilation gets switched off, UseCompiler
+ // is set to false
+ if (!method->has_compiled_code() && UseCompiler) {
+ method_invocation_event(method, thread);
+ } else {
+ // Force counter overflow on method entry, even if no compilation
+ // happened. (The method_invocation_event call does this also.)
+ reset_counter_for_invocation_event(method);
+ }
+ // compilation at an invocation overflow no longer goes and retries test for
+ // compiled method. We always run the loser of the race as interpreted.
+ // so return NULL
+ return NULL;
+ } else {
+ // counter overflow in a loop => try to do on-stack-replacement
+ nmethod* osr_nm = method->lookup_osr_nmethod_for(bci, CompLevel_highest_tier, true);
+ NOT_PRODUCT(trace_osr_request(method, osr_nm, bci));
+ // when code cache is full, we should not compile any more...
+ if (osr_nm == NULL && UseCompiler) {
+ method_back_branch_event(method, bci, thread);
+ osr_nm = method->lookup_osr_nmethod_for(bci, CompLevel_highest_tier, true);
+ }
+ if (osr_nm == NULL) {
+ reset_counter_for_back_branch_event(method);
+ return NULL;
+ }
+ return osr_nm;
+ }
+ return NULL;
+}
+
+#ifndef PRODUCT
+void SimpleCompPolicy::trace_frequency_counter_overflow(const methodHandle& m, int branch_bci, int bci) {
+ if (TraceInvocationCounterOverflow) {
+ MethodCounters* mcs = m->method_counters();
+ assert(mcs != NULL, "MethodCounters cannot be NULL for profiling");
+ InvocationCounter* ic = mcs->invocation_counter();
+ InvocationCounter* bc = mcs->backedge_counter();
+ ResourceMark rm;
+ if (bci == InvocationEntryBci) {
+ tty->print("comp-policy cntr ovfl @ %d in entry of ", bci);
+ } else {
+ tty->print("comp-policy cntr ovfl @ %d in loop of ", bci);
+ }
+ m->print_value();
+ tty->cr();
+ ic->print();
+ bc->print();
+ if (ProfileInterpreter) {
+ if (bci != InvocationEntryBci) {
+ MethodData* mdo = m->method_data();
+ if (mdo != NULL) {
+ ProfileData *pd = mdo->bci_to_data(branch_bci);
+ if (pd == NULL) {
+ tty->print_cr("back branch count = N/A (missing ProfileData)");
+ } else {
+ tty->print_cr("back branch count = %d", pd->as_JumpData()->taken());
+ }
+ }
+ }
+ }
+ }
+}
+
+void SimpleCompPolicy::trace_osr_request(const methodHandle& method, nmethod* osr, int bci) {
+ if (TraceOnStackReplacement) {
+ ResourceMark rm;
+ tty->print(osr != NULL ? "Reused OSR entry for " : "Requesting OSR entry for ");
+ method->print_short_name(tty);
+ tty->print_cr(" at bci %d", bci);
+ }
+}
+#endif // !PRODUCT
+
+void SimpleCompPolicy::method_invocation_event(const methodHandle& m, JavaThread* thread) {
+ const int comp_level = CompLevel_highest_tier;
+ const int hot_count = m->invocation_count();
+ reset_counter_for_invocation_event(m);
+
+ if (is_compilation_enabled() && can_be_compiled(m, comp_level)) {
+ CompiledMethod* nm = m->code();
+ if (nm == NULL ) {
+ CompileBroker::compile_method(m, InvocationEntryBci, comp_level, m, hot_count, CompileTask::Reason_InvocationCount, thread);
+ }
+ }
+}
+
+void SimpleCompPolicy::method_back_branch_event(const methodHandle& m, int bci, JavaThread* thread) {
+ const int comp_level = CompLevel_highest_tier;
+ const int hot_count = m->backedge_count();
+
+ if (is_compilation_enabled() && can_be_osr_compiled(m, comp_level)) {
+ CompileBroker::compile_method(m, bci, comp_level, m, hot_count, CompileTask::Reason_BackedgeCount, thread);
+ NOT_PRODUCT(trace_osr_completion(m->lookup_osr_nmethod_for(bci, comp_level, true));)
+ }
+}