--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/runtime/tieredThresholdPolicy.cpp Fri Aug 10 00:20:15 2018 +0200
@@ -0,0 +1,978 @@
+/*
+ * Copyright (c) 2010, 2018, 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 "compiler/compileBroker.hpp"
+#include "compiler/compilerOracle.hpp"
+#include "memory/resourceArea.hpp"
+#include "runtime/arguments.hpp"
+#include "runtime/handles.inline.hpp"
+#include "runtime/safepointVerifiers.hpp"
+#include "runtime/tieredThresholdPolicy.hpp"
+#include "code/scopeDesc.hpp"
+#include "oops/method.inline.hpp"
+#if INCLUDE_JVMCI
+#include "jvmci/jvmciRuntime.hpp"
+#endif
+
+#ifdef TIERED
+
+template<CompLevel level>
+bool TieredThresholdPolicy::call_predicate_helper(int i, int b, double scale, Method* method) {
+ double threshold_scaling;
+ if (CompilerOracle::has_option_value(method, "CompileThresholdScaling", threshold_scaling)) {
+ scale *= threshold_scaling;
+ }
+ switch(level) {
+ case CompLevel_aot:
+ return (i >= Tier3AOTInvocationThreshold * scale) ||
+ (i >= Tier3AOTMinInvocationThreshold * scale && i + b >= Tier3AOTCompileThreshold * scale);
+ case CompLevel_none:
+ case CompLevel_limited_profile:
+ return (i >= Tier3InvocationThreshold * scale) ||
+ (i >= Tier3MinInvocationThreshold * scale && i + b >= Tier3CompileThreshold * scale);
+ case CompLevel_full_profile:
+ return (i >= Tier4InvocationThreshold * scale) ||
+ (i >= Tier4MinInvocationThreshold * scale && i + b >= Tier4CompileThreshold * scale);
+ }
+ return true;
+}
+
+template<CompLevel level>
+bool TieredThresholdPolicy::loop_predicate_helper(int i, int b, double scale, Method* method) {
+ double threshold_scaling;
+ if (CompilerOracle::has_option_value(method, "CompileThresholdScaling", threshold_scaling)) {
+ scale *= threshold_scaling;
+ }
+ switch(level) {
+ case CompLevel_aot:
+ return b >= Tier3AOTBackEdgeThreshold * scale;
+ case CompLevel_none:
+ case CompLevel_limited_profile:
+ return b >= Tier3BackEdgeThreshold * scale;
+ case CompLevel_full_profile:
+ return b >= Tier4BackEdgeThreshold * scale;
+ }
+ return true;
+}
+
+// Simple methods are as good being compiled with C1 as C2.
+// Determine if a given method is such a case.
+bool TieredThresholdPolicy::is_trivial(Method* method) {
+ if (method->is_accessor() ||
+ method->is_constant_getter()) {
+ return true;
+ }
+#if INCLUDE_JVMCI
+ if (UseJVMCICompiler) {
+ AbstractCompiler* comp = CompileBroker::compiler(CompLevel_full_optimization);
+ if (TieredCompilation && comp != NULL && comp->is_trivial(method)) {
+ return true;
+ }
+ }
+#endif
+ if (method->has_loops() || method->code_size() >= 15) {
+ return false;
+ }
+ MethodData* mdo = method->method_data();
+ if (mdo != NULL && !mdo->would_profile() &&
+ (method->code_size() < 5 || (mdo->num_blocks() < 4))) {
+ return true;
+ }
+ return false;
+}
+
+CompLevel TieredThresholdPolicy::comp_level(Method* method) {
+ CompiledMethod *nm = method->code();
+ if (nm != NULL && nm->is_in_use()) {
+ return (CompLevel)nm->comp_level();
+ }
+ return CompLevel_none;
+}
+
+void TieredThresholdPolicy::print_counters(const char* prefix, const methodHandle& mh) {
+ int invocation_count = mh->invocation_count();
+ int backedge_count = mh->backedge_count();
+ MethodData* mdh = mh->method_data();
+ int mdo_invocations = 0, mdo_backedges = 0;
+ int mdo_invocations_start = 0, mdo_backedges_start = 0;
+ if (mdh != NULL) {
+ mdo_invocations = mdh->invocation_count();
+ mdo_backedges = mdh->backedge_count();
+ mdo_invocations_start = mdh->invocation_count_start();
+ mdo_backedges_start = mdh->backedge_count_start();
+ }
+ tty->print(" %stotal=%d,%d %smdo=%d(%d),%d(%d)", prefix,
+ invocation_count, backedge_count, prefix,
+ mdo_invocations, mdo_invocations_start,
+ mdo_backedges, mdo_backedges_start);
+ tty->print(" %smax levels=%d,%d", prefix,
+ mh->highest_comp_level(), mh->highest_osr_comp_level());
+}
+
+// Print an event.
+void TieredThresholdPolicy::print_event(EventType type, const methodHandle& mh, const methodHandle& imh,
+ int bci, CompLevel level) {
+ bool inlinee_event = mh() != imh();
+
+ ttyLocker tty_lock;
+ tty->print("%lf: [", os::elapsedTime());
+
+ switch(type) {
+ case CALL:
+ tty->print("call");
+ break;
+ case LOOP:
+ tty->print("loop");
+ break;
+ case COMPILE:
+ tty->print("compile");
+ break;
+ case REMOVE_FROM_QUEUE:
+ tty->print("remove-from-queue");
+ break;
+ case UPDATE_IN_QUEUE:
+ tty->print("update-in-queue");
+ break;
+ case REPROFILE:
+ tty->print("reprofile");
+ break;
+ case MAKE_NOT_ENTRANT:
+ tty->print("make-not-entrant");
+ break;
+ default:
+ tty->print("unknown");
+ }
+
+ tty->print(" level=%d ", level);
+
+ ResourceMark rm;
+ char *method_name = mh->name_and_sig_as_C_string();
+ tty->print("[%s", method_name);
+ if (inlinee_event) {
+ char *inlinee_name = imh->name_and_sig_as_C_string();
+ tty->print(" [%s]] ", inlinee_name);
+ }
+ else tty->print("] ");
+ tty->print("@%d queues=%d,%d", bci, CompileBroker::queue_size(CompLevel_full_profile),
+ CompileBroker::queue_size(CompLevel_full_optimization));
+
+ print_specific(type, mh, imh, bci, level);
+
+ if (type != COMPILE) {
+ print_counters("", mh);
+ if (inlinee_event) {
+ print_counters("inlinee ", imh);
+ }
+ tty->print(" compilable=");
+ bool need_comma = false;
+ if (!mh->is_not_compilable(CompLevel_full_profile)) {
+ tty->print("c1");
+ need_comma = true;
+ }
+ if (!mh->is_not_osr_compilable(CompLevel_full_profile)) {
+ if (need_comma) tty->print(",");
+ tty->print("c1-osr");
+ need_comma = true;
+ }
+ if (!mh->is_not_compilable(CompLevel_full_optimization)) {
+ if (need_comma) tty->print(",");
+ tty->print("c2");
+ need_comma = true;
+ }
+ if (!mh->is_not_osr_compilable(CompLevel_full_optimization)) {
+ if (need_comma) tty->print(",");
+ tty->print("c2-osr");
+ }
+ tty->print(" status=");
+ if (mh->queued_for_compilation()) {
+ tty->print("in-queue");
+ } else tty->print("idle");
+ }
+ tty->print_cr("]");
+}
+
+void TieredThresholdPolicy::initialize() {
+ int count = CICompilerCount;
+#ifdef _LP64
+ // Turn on ergonomic compiler count selection
+ if (FLAG_IS_DEFAULT(CICompilerCountPerCPU) && FLAG_IS_DEFAULT(CICompilerCount)) {
+ FLAG_SET_DEFAULT(CICompilerCountPerCPU, true);
+ }
+ if (CICompilerCountPerCPU) {
+ // Simple log n seems to grow too slowly for tiered, try something faster: log n * log log n
+ int log_cpu = log2_intptr(os::active_processor_count());
+ int loglog_cpu = log2_intptr(MAX2(log_cpu, 1));
+ count = MAX2(log_cpu * loglog_cpu * 3 / 2, 2);
+ FLAG_SET_ERGO(intx, CICompilerCount, count);
+ }
+#else
+ // On 32-bit systems, the number of compiler threads is limited to 3.
+ // On these systems, the virtual address space available to the JVM
+ // is usually limited to 2-4 GB (the exact value depends on the platform).
+ // As the compilers (especially C2) can consume a large amount of
+ // memory, scaling the number of compiler threads with the number of
+ // available cores can result in the exhaustion of the address space
+ /// available to the VM and thus cause the VM to crash.
+ if (FLAG_IS_DEFAULT(CICompilerCount)) {
+ count = 3;
+ FLAG_SET_ERGO(intx, CICompilerCount, count);
+ }
+#endif
+
+ if (TieredStopAtLevel < CompLevel_full_optimization) {
+ // No C2 compiler thread required
+ set_c1_count(count);
+ } else {
+ set_c1_count(MAX2(count / 3, 1));
+ set_c2_count(MAX2(count - c1_count(), 1));
+ }
+ assert(count == c1_count() + c2_count(), "inconsistent compiler thread count");
+
+ // Some inlining tuning
+#ifdef X86
+ if (FLAG_IS_DEFAULT(InlineSmallCode)) {
+ FLAG_SET_DEFAULT(InlineSmallCode, 2000);
+ }
+#endif
+
+#if defined SPARC || defined AARCH64
+ if (FLAG_IS_DEFAULT(InlineSmallCode)) {
+ FLAG_SET_DEFAULT(InlineSmallCode, 2500);
+ }
+#endif
+
+ set_increase_threshold_at_ratio();
+ set_start_time(os::javaTimeMillis());
+}
+
+void TieredThresholdPolicy::set_carry_if_necessary(InvocationCounter *counter) {
+ if (!counter->carry() && counter->count() > InvocationCounter::count_limit / 2) {
+ counter->set_carry_flag();
+ }
+}
+
+// Set carry flags on the counters if necessary
+void TieredThresholdPolicy::handle_counter_overflow(Method* method) {
+ MethodCounters *mcs = method->method_counters();
+ if (mcs != NULL) {
+ set_carry_if_necessary(mcs->invocation_counter());
+ set_carry_if_necessary(mcs->backedge_counter());
+ }
+ MethodData* mdo = method->method_data();
+ if (mdo != NULL) {
+ set_carry_if_necessary(mdo->invocation_counter());
+ set_carry_if_necessary(mdo->backedge_counter());
+ }
+}
+
+// Called with the queue locked and with at least one element
+CompileTask* TieredThresholdPolicy::select_task(CompileQueue* compile_queue) {
+ CompileTask *max_blocking_task = NULL;
+ CompileTask *max_task = NULL;
+ Method* max_method = NULL;
+ jlong t = os::javaTimeMillis();
+ // Iterate through the queue and find a method with a maximum rate.
+ for (CompileTask* task = compile_queue->first(); task != NULL;) {
+ CompileTask* next_task = task->next();
+ Method* method = task->method();
+ update_rate(t, method);
+ if (max_task == NULL) {
+ max_task = task;
+ max_method = method;
+ } else {
+ // If a method has been stale for some time, remove it from the queue.
+ // Blocking tasks and tasks submitted from whitebox API don't become stale
+ if (task->can_become_stale() && is_stale(t, TieredCompileTaskTimeout, method) && !is_old(method)) {
+ if (PrintTieredEvents) {
+ print_event(REMOVE_FROM_QUEUE, method, method, task->osr_bci(), (CompLevel)task->comp_level());
+ }
+ compile_queue->remove_and_mark_stale(task);
+ method->clear_queued_for_compilation();
+ task = next_task;
+ continue;
+ }
+
+ // Select a method with a higher rate
+ if (compare_methods(method, max_method)) {
+ max_task = task;
+ max_method = method;
+ }
+ }
+
+ if (task->is_blocking()) {
+ if (max_blocking_task == NULL || compare_methods(method, max_blocking_task->method())) {
+ max_blocking_task = task;
+ }
+ }
+
+ task = next_task;
+ }
+
+ if (max_blocking_task != NULL) {
+ // 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.
+ max_task = max_blocking_task;
+ max_method = max_task->method();
+ }
+
+ if (max_task != NULL && max_task->comp_level() == CompLevel_full_profile &&
+ TieredStopAtLevel > CompLevel_full_profile &&
+ max_method != NULL && is_method_profiled(max_method)) {
+ max_task->set_comp_level(CompLevel_limited_profile);
+ if (PrintTieredEvents) {
+ print_event(UPDATE_IN_QUEUE, max_method, max_method, max_task->osr_bci(), (CompLevel)max_task->comp_level());
+ }
+ }
+
+ return max_task;
+}
+
+void TieredThresholdPolicy::reprofile(ScopeDesc* trap_scope, bool is_osr) {
+ for (ScopeDesc* sd = trap_scope;; sd = sd->sender()) {
+ if (PrintTieredEvents) {
+ methodHandle mh(sd->method());
+ print_event(REPROFILE, mh, mh, InvocationEntryBci, CompLevel_none);
+ }
+ MethodData* mdo = sd->method()->method_data();
+ if (mdo != NULL) {
+ mdo->reset_start_counters();
+ }
+ if (sd->is_top()) break;
+ }
+}
+
+nmethod* TieredThresholdPolicy::event(const methodHandle& method, const methodHandle& inlinee,
+ int branch_bci, int bci, CompLevel comp_level, CompiledMethod* nm, JavaThread* thread) {
+ if (comp_level == CompLevel_none &&
+ JvmtiExport::can_post_interpreter_events() &&
+ thread->is_interp_only_mode()) {
+ return NULL;
+ }
+ if (CompileTheWorld || ReplayCompiles) {
+ // Don't trigger other compiles in testing mode
+ return NULL;
+ }
+
+ handle_counter_overflow(method());
+ if (method() != inlinee()) {
+ handle_counter_overflow(inlinee());
+ }
+
+ if (PrintTieredEvents) {
+ print_event(bci == InvocationEntryBci ? CALL : LOOP, method, inlinee, bci, comp_level);
+ }
+
+ if (bci == InvocationEntryBci) {
+ method_invocation_event(method, inlinee, comp_level, nm, thread);
+ } else {
+ // method == inlinee if the event originated in the main method
+ method_back_branch_event(method, inlinee, bci, comp_level, nm, thread);
+ // Check if event led to a higher level OSR compilation
+ nmethod* osr_nm = inlinee->lookup_osr_nmethod_for(bci, comp_level, false);
+ if (osr_nm != NULL && osr_nm->comp_level() > comp_level) {
+ // Perform OSR with new nmethod
+ return osr_nm;
+ }
+ }
+ return NULL;
+}
+
+// Check if the method can be compiled, change level if necessary
+void TieredThresholdPolicy::compile(const methodHandle& mh, int bci, CompLevel level, JavaThread* thread) {
+ assert(level <= TieredStopAtLevel, "Invalid compilation level");
+ if (level == CompLevel_none) {
+ return;
+ }
+ if (level == CompLevel_aot) {
+ if (mh->has_aot_code()) {
+ if (PrintTieredEvents) {
+ print_event(COMPILE, mh, mh, bci, level);
+ }
+ MutexLocker ml(Compile_lock);
+ NoSafepointVerifier nsv;
+ if (mh->has_aot_code() && mh->code() != mh->aot_code()) {
+ mh->aot_code()->make_entrant();
+ if (mh->has_compiled_code()) {
+ mh->code()->make_not_entrant();
+ }
+ Method::set_code(mh, mh->aot_code());
+ }
+ }
+ return;
+ }
+
+ // Check if the method can be compiled. If it cannot be compiled with C1, continue profiling
+ // in the interpreter and then compile with C2 (the transition function will request that,
+ // see common() ). If the method cannot be compiled with C2 but still can with C1, compile it with
+ // pure C1.
+ if (!can_be_compiled(mh, level)) {
+ if (level == CompLevel_full_optimization && can_be_compiled(mh, CompLevel_simple)) {
+ compile(mh, bci, CompLevel_simple, thread);
+ }
+ return;
+ }
+ if (bci != InvocationEntryBci && mh->is_not_osr_compilable(level)) {
+ return;
+ }
+ if (!CompileBroker::compilation_is_in_queue(mh)) {
+ if (PrintTieredEvents) {
+ print_event(COMPILE, mh, mh, bci, level);
+ }
+ submit_compile(mh, bci, level, thread);
+ }
+}
+
+// Update the rate and submit compile
+void TieredThresholdPolicy::submit_compile(const methodHandle& mh, int bci, CompLevel level, JavaThread* thread) {
+ int hot_count = (bci == InvocationEntryBci) ? mh->invocation_count() : mh->backedge_count();
+ update_rate(os::javaTimeMillis(), mh());
+ CompileBroker::compile_method(mh, bci, level, mh, hot_count, CompileTask::Reason_Tiered, thread);
+}
+
+// Print an event.
+void TieredThresholdPolicy::print_specific(EventType type, const methodHandle& mh, const methodHandle& imh,
+ int bci, CompLevel level) {
+ tty->print(" rate=");
+ if (mh->prev_time() == 0) tty->print("n/a");
+ else tty->print("%f", mh->rate());
+
+ tty->print(" k=%.2lf,%.2lf", threshold_scale(CompLevel_full_profile, Tier3LoadFeedback),
+ threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback));
+
+}
+
+// update_rate() is called from select_task() while holding a compile queue lock.
+void TieredThresholdPolicy::update_rate(jlong t, Method* m) {
+ // Skip update if counters are absent.
+ // Can't allocate them since we are holding compile queue lock.
+ if (m->method_counters() == NULL) return;
+
+ if (is_old(m)) {
+ // We don't remove old methods from the queue,
+ // so we can just zero the rate.
+ m->set_rate(0);
+ return;
+ }
+
+ // We don't update the rate if we've just came out of a safepoint.
+ // delta_s is the time since last safepoint in milliseconds.
+ jlong delta_s = t - SafepointSynchronize::end_of_last_safepoint();
+ jlong delta_t = t - (m->prev_time() != 0 ? m->prev_time() : start_time()); // milliseconds since the last measurement
+ // How many events were there since the last time?
+ int event_count = m->invocation_count() + m->backedge_count();
+ int delta_e = event_count - m->prev_event_count();
+
+ // We should be running for at least 1ms.
+ if (delta_s >= TieredRateUpdateMinTime) {
+ // And we must've taken the previous point at least 1ms before.
+ if (delta_t >= TieredRateUpdateMinTime && delta_e > 0) {
+ m->set_prev_time(t);
+ m->set_prev_event_count(event_count);
+ m->set_rate((float)delta_e / (float)delta_t); // Rate is events per millisecond
+ } else {
+ if (delta_t > TieredRateUpdateMaxTime && delta_e == 0) {
+ // If nothing happened for 25ms, zero the rate. Don't modify prev values.
+ m->set_rate(0);
+ }
+ }
+ }
+}
+
+// Check if this method has been stale from a given number of milliseconds.
+// See select_task().
+bool TieredThresholdPolicy::is_stale(jlong t, jlong timeout, Method* m) {
+ jlong delta_s = t - SafepointSynchronize::end_of_last_safepoint();
+ jlong delta_t = t - m->prev_time();
+ if (delta_t > timeout && delta_s > timeout) {
+ int event_count = m->invocation_count() + m->backedge_count();
+ int delta_e = event_count - m->prev_event_count();
+ // Return true if there were no events.
+ return delta_e == 0;
+ }
+ return false;
+}
+
+// We don't remove old methods from the compile queue even if they have
+// very low activity. See select_task().
+bool TieredThresholdPolicy::is_old(Method* method) {
+ return method->invocation_count() > 50000 || method->backedge_count() > 500000;
+}
+
+double TieredThresholdPolicy::weight(Method* method) {
+ return (double)(method->rate() + 1) *
+ (method->invocation_count() + 1) * (method->backedge_count() + 1);
+}
+
+// Apply heuristics and return true if x should be compiled before y
+bool TieredThresholdPolicy::compare_methods(Method* x, Method* y) {
+ if (x->highest_comp_level() > y->highest_comp_level()) {
+ // recompilation after deopt
+ return true;
+ } else
+ if (x->highest_comp_level() == y->highest_comp_level()) {
+ if (weight(x) > weight(y)) {
+ return true;
+ }
+ }
+ return false;
+}
+
+// Is method profiled enough?
+bool TieredThresholdPolicy::is_method_profiled(Method* method) {
+ MethodData* mdo = method->method_data();
+ if (mdo != NULL) {
+ int i = mdo->invocation_count_delta();
+ int b = mdo->backedge_count_delta();
+ return call_predicate_helper<CompLevel_full_profile>(i, b, 1, method);
+ }
+ return false;
+}
+
+double TieredThresholdPolicy::threshold_scale(CompLevel level, int feedback_k) {
+ double queue_size = CompileBroker::queue_size(level);
+ int comp_count = compiler_count(level);
+ double k = queue_size / (feedback_k * comp_count) + 1;
+
+ // Increase C1 compile threshold when the code cache is filled more
+ // than specified by IncreaseFirstTierCompileThresholdAt percentage.
+ // The main intention is to keep enough free space for C2 compiled code
+ // to achieve peak performance if the code cache is under stress.
+ if ((TieredStopAtLevel == CompLevel_full_optimization) && (level != CompLevel_full_optimization)) {
+ double current_reverse_free_ratio = CodeCache::reverse_free_ratio(CodeCache::get_code_blob_type(level));
+ if (current_reverse_free_ratio > _increase_threshold_at_ratio) {
+ k *= exp(current_reverse_free_ratio - _increase_threshold_at_ratio);
+ }
+ }
+ return k;
+}
+
+// Call and loop predicates determine whether a transition to a higher
+// compilation level should be performed (pointers to predicate functions
+// are passed to common()).
+// Tier?LoadFeedback is basically a coefficient that determines of
+// how many methods per compiler thread can be in the queue before
+// the threshold values double.
+bool TieredThresholdPolicy::loop_predicate(int i, int b, CompLevel cur_level, Method* method) {
+ switch(cur_level) {
+ case CompLevel_aot: {
+ double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);
+ return loop_predicate_helper<CompLevel_aot>(i, b, k, method);
+ }
+ case CompLevel_none:
+ case CompLevel_limited_profile: {
+ double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);
+ return loop_predicate_helper<CompLevel_none>(i, b, k, method);
+ }
+ case CompLevel_full_profile: {
+ double k = threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback);
+ return loop_predicate_helper<CompLevel_full_profile>(i, b, k, method);
+ }
+ default:
+ return true;
+ }
+}
+
+bool TieredThresholdPolicy::call_predicate(int i, int b, CompLevel cur_level, Method* method) {
+ switch(cur_level) {
+ case CompLevel_aot: {
+ double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);
+ return call_predicate_helper<CompLevel_aot>(i, b, k, method);
+ }
+ case CompLevel_none:
+ case CompLevel_limited_profile: {
+ double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback);
+ return call_predicate_helper<CompLevel_none>(i, b, k, method);
+ }
+ case CompLevel_full_profile: {
+ double k = threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback);
+ return call_predicate_helper<CompLevel_full_profile>(i, b, k, method);
+ }
+ default:
+ return true;
+ }
+}
+
+// Determine is a method is mature.
+bool TieredThresholdPolicy::is_mature(Method* method) {
+ if (is_trivial(method)) return true;
+ MethodData* mdo = method->method_data();
+ if (mdo != NULL) {
+ int i = mdo->invocation_count();
+ int b = mdo->backedge_count();
+ double k = ProfileMaturityPercentage / 100.0;
+ return call_predicate_helper<CompLevel_full_profile>(i, b, k, method) ||
+ loop_predicate_helper<CompLevel_full_profile>(i, b, k, method);
+ }
+ return false;
+}
+
+// If a method is old enough and is still in the interpreter we would want to
+// start profiling without waiting for the compiled method to arrive.
+// We also take the load on compilers into the account.
+bool TieredThresholdPolicy::should_create_mdo(Method* method, CompLevel cur_level) {
+ if (cur_level == CompLevel_none &&
+ CompileBroker::queue_size(CompLevel_full_optimization) <=
+ Tier3DelayOn * compiler_count(CompLevel_full_optimization)) {
+ int i = method->invocation_count();
+ int b = method->backedge_count();
+ double k = Tier0ProfilingStartPercentage / 100.0;
+ return call_predicate_helper<CompLevel_none>(i, b, k, method) || loop_predicate_helper<CompLevel_none>(i, b, k, method);
+ }
+ return false;
+}
+
+// Inlining control: if we're compiling a profiled method with C1 and the callee
+// is known to have OSRed in a C2 version, don't inline it.
+bool TieredThresholdPolicy::should_not_inline(ciEnv* env, ciMethod* callee) {
+ CompLevel comp_level = (CompLevel)env->comp_level();
+ if (comp_level == CompLevel_full_profile ||
+ comp_level == CompLevel_limited_profile) {
+ return callee->highest_osr_comp_level() == CompLevel_full_optimization;
+ }
+ return false;
+}
+
+// Create MDO if necessary.
+void TieredThresholdPolicy::create_mdo(const methodHandle& mh, JavaThread* THREAD) {
+ if (mh->is_native() ||
+ mh->is_abstract() ||
+ mh->is_accessor() ||
+ mh->is_constant_getter()) {
+ return;
+ }
+ if (mh->method_data() == NULL) {
+ Method::build_interpreter_method_data(mh, CHECK_AND_CLEAR);
+ }
+}
+
+
+/*
+ * Method states:
+ * 0 - interpreter (CompLevel_none)
+ * 1 - pure C1 (CompLevel_simple)
+ * 2 - C1 with invocation and backedge counting (CompLevel_limited_profile)
+ * 3 - C1 with full profiling (CompLevel_full_profile)
+ * 4 - C2 (CompLevel_full_optimization)
+ *
+ * Common state transition patterns:
+ * a. 0 -> 3 -> 4.
+ * The most common path. But note that even in this straightforward case
+ * profiling can start at level 0 and finish at level 3.
+ *
+ * b. 0 -> 2 -> 3 -> 4.
+ * This case occurs when the load on C2 is deemed too high. So, instead of transitioning
+ * into state 3 directly and over-profiling while a method is in the C2 queue we transition to
+ * level 2 and wait until the load on C2 decreases. This path is disabled for OSRs.
+ *
+ * c. 0 -> (3->2) -> 4.
+ * In this case we enqueue a method for compilation at level 3, but the C1 queue is long enough
+ * to enable the profiling to fully occur at level 0. In this case we change the compilation level
+ * of the method to 2 while the request is still in-queue, because it'll allow it to run much faster
+ * without full profiling while c2 is compiling.
+ *
+ * d. 0 -> 3 -> 1 or 0 -> 2 -> 1.
+ * After a method was once compiled with C1 it can be identified as trivial and be compiled to
+ * level 1. These transition can also occur if a method can't be compiled with C2 but can with C1.
+ *
+ * e. 0 -> 4.
+ * This can happen if a method fails C1 compilation (it will still be profiled in the interpreter)
+ * or because of a deopt that didn't require reprofiling (compilation won't happen in this case because
+ * the compiled version already exists).
+ *
+ * Note that since state 0 can be reached from any other state via deoptimization different loops
+ * are possible.
+ *
+ */
+
+// Common transition function. Given a predicate determines if a method should transition to another level.
+CompLevel TieredThresholdPolicy::common(Predicate p, Method* method, CompLevel cur_level, bool disable_feedback) {
+ CompLevel next_level = cur_level;
+ int i = method->invocation_count();
+ int b = method->backedge_count();
+
+ if (is_trivial(method)) {
+ next_level = CompLevel_simple;
+ } else {
+ switch(cur_level) {
+ default: break;
+ case CompLevel_aot: {
+ // If we were at full profile level, would we switch to full opt?
+ if (common(p, method, CompLevel_full_profile, disable_feedback) == CompLevel_full_optimization) {
+ next_level = CompLevel_full_optimization;
+ } else if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <=
+ Tier3DelayOff * compiler_count(CompLevel_full_optimization) &&
+ (this->*p)(i, b, cur_level, method))) {
+ next_level = CompLevel_full_profile;
+ }
+ }
+ break;
+ case CompLevel_none:
+ // If we were at full profile level, would we switch to full opt?
+ if (common(p, method, CompLevel_full_profile, disable_feedback) == CompLevel_full_optimization) {
+ next_level = CompLevel_full_optimization;
+ } else if ((this->*p)(i, b, cur_level, method)) {
+#if INCLUDE_JVMCI
+ if (EnableJVMCI && UseJVMCICompiler) {
+ // Since JVMCI takes a while to warm up, its queue inevitably backs up during
+ // early VM execution. As of 2014-06-13, JVMCI's inliner assumes that the root
+ // compilation method and all potential inlinees have mature profiles (which
+ // includes type profiling). If it sees immature profiles, JVMCI's inliner
+ // can perform pathologically bad (e.g., causing OutOfMemoryErrors due to
+ // exploring/inlining too many graphs). Since a rewrite of the inliner is
+ // in progress, we simply disable the dialing back heuristic for now and will
+ // revisit this decision once the new inliner is completed.
+ next_level = CompLevel_full_profile;
+ } else
+#endif
+ {
+ // C1-generated fully profiled code is about 30% slower than the limited profile
+ // code that has only invocation and backedge counters. The observation is that
+ // if C2 queue is large enough we can spend too much time in the fully profiled code
+ // while waiting for C2 to pick the method from the queue. To alleviate this problem
+ // we introduce a feedback on the C2 queue size. If the C2 queue is sufficiently long
+ // we choose to compile a limited profiled version and then recompile with full profiling
+ // when the load on C2 goes down.
+ if (!disable_feedback && CompileBroker::queue_size(CompLevel_full_optimization) >
+ Tier3DelayOn * compiler_count(CompLevel_full_optimization)) {
+ next_level = CompLevel_limited_profile;
+ } else {
+ next_level = CompLevel_full_profile;
+ }
+ }
+ }
+ break;
+ case CompLevel_limited_profile:
+ if (is_method_profiled(method)) {
+ // Special case: we got here because this method was fully profiled in the interpreter.
+ next_level = CompLevel_full_optimization;
+ } else {
+ MethodData* mdo = method->method_data();
+ if (mdo != NULL) {
+ if (mdo->would_profile()) {
+ if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <=
+ Tier3DelayOff * compiler_count(CompLevel_full_optimization) &&
+ (this->*p)(i, b, cur_level, method))) {
+ next_level = CompLevel_full_profile;
+ }
+ } else {
+ next_level = CompLevel_full_optimization;
+ }
+ } else {
+ // If there is no MDO we need to profile
+ if (disable_feedback || (CompileBroker::queue_size(CompLevel_full_optimization) <=
+ Tier3DelayOff * compiler_count(CompLevel_full_optimization) &&
+ (this->*p)(i, b, cur_level, method))) {
+ next_level = CompLevel_full_profile;
+ }
+ }
+ }
+ break;
+ case CompLevel_full_profile:
+ {
+ MethodData* mdo = method->method_data();
+ if (mdo != NULL) {
+ if (mdo->would_profile()) {
+ int mdo_i = mdo->invocation_count_delta();
+ int mdo_b = mdo->backedge_count_delta();
+ if ((this->*p)(mdo_i, mdo_b, cur_level, method)) {
+ next_level = CompLevel_full_optimization;
+ }
+ } else {
+ next_level = CompLevel_full_optimization;
+ }
+ }
+ }
+ break;
+ }
+ }
+ return MIN2(next_level, (CompLevel)TieredStopAtLevel);
+}
+
+// Determine if a method should be compiled with a normal entry point at a different level.
+CompLevel TieredThresholdPolicy::call_event(Method* method, CompLevel cur_level, JavaThread * thread) {
+ CompLevel osr_level = MIN2((CompLevel) method->highest_osr_comp_level(),
+ common(&TieredThresholdPolicy::loop_predicate, method, cur_level, true));
+ CompLevel next_level = common(&TieredThresholdPolicy::call_predicate, method, cur_level);
+
+ // If OSR method level is greater than the regular method level, the levels should be
+ // equalized by raising the regular method level in order to avoid OSRs during each
+ // invocation of the method.
+ if (osr_level == CompLevel_full_optimization && cur_level == CompLevel_full_profile) {
+ MethodData* mdo = method->method_data();
+ guarantee(mdo != NULL, "MDO should not be NULL");
+ if (mdo->invocation_count() >= 1) {
+ next_level = CompLevel_full_optimization;
+ }
+ } else {
+ next_level = MAX2(osr_level, next_level);
+ }
+#if INCLUDE_JVMCI
+ if (UseJVMCICompiler) {
+ next_level = JVMCIRuntime::adjust_comp_level(method, false, next_level, thread);
+ }
+#endif
+ return next_level;
+}
+
+// Determine if we should do an OSR compilation of a given method.
+CompLevel TieredThresholdPolicy::loop_event(Method* method, CompLevel cur_level, JavaThread* thread) {
+ CompLevel next_level = common(&TieredThresholdPolicy::loop_predicate, method, cur_level, true);
+ if (cur_level == CompLevel_none) {
+ // If there is a live OSR method that means that we deopted to the interpreter
+ // for the transition.
+ CompLevel osr_level = MIN2((CompLevel)method->highest_osr_comp_level(), next_level);
+ if (osr_level > CompLevel_none) {
+ return osr_level;
+ }
+ }
+#if INCLUDE_JVMCI
+ if (UseJVMCICompiler) {
+ next_level = JVMCIRuntime::adjust_comp_level(method, true, next_level, thread);
+ }
+#endif
+ return next_level;
+}
+
+bool TieredThresholdPolicy::maybe_switch_to_aot(const methodHandle& mh, CompLevel cur_level, CompLevel next_level, JavaThread* thread) {
+ if (UseAOT && !delay_compilation_during_startup()) {
+ if (cur_level == CompLevel_full_profile || cur_level == CompLevel_none) {
+ // If the current level is full profile or interpreter and we're switching to any other level,
+ // activate the AOT code back first so that we won't waste time overprofiling.
+ compile(mh, InvocationEntryBci, CompLevel_aot, thread);
+ // Fall through for JIT compilation.
+ }
+ if (next_level == CompLevel_limited_profile && cur_level != CompLevel_aot && mh->has_aot_code()) {
+ // If the next level is limited profile, use the aot code (if there is any),
+ // since it's essentially the same thing.
+ compile(mh, InvocationEntryBci, CompLevel_aot, thread);
+ // Not need to JIT, we're done.
+ return true;
+ }
+ }
+ return false;
+}
+
+
+// Handle the invocation event.
+void TieredThresholdPolicy::method_invocation_event(const methodHandle& mh, const methodHandle& imh,
+ CompLevel level, CompiledMethod* nm, JavaThread* thread) {
+ if (should_create_mdo(mh(), level)) {
+ create_mdo(mh, thread);
+ }
+ CompLevel next_level = call_event(mh(), level, thread);
+ if (next_level != level) {
+ if (maybe_switch_to_aot(mh, level, next_level, thread)) {
+ // No JITting necessary
+ return;
+ }
+ if (is_compilation_enabled() && !CompileBroker::compilation_is_in_queue(mh)) {
+ compile(mh, InvocationEntryBci, next_level, thread);
+ }
+ }
+}
+
+// Handle the back branch event. Notice that we can compile the method
+// with a regular entry from here.
+void TieredThresholdPolicy::method_back_branch_event(const methodHandle& mh, const methodHandle& imh,
+ int bci, CompLevel level, CompiledMethod* nm, JavaThread* thread) {
+ if (should_create_mdo(mh(), level)) {
+ create_mdo(mh, thread);
+ }
+ // Check if MDO should be created for the inlined method
+ if (should_create_mdo(imh(), level)) {
+ create_mdo(imh, thread);
+ }
+
+ if (is_compilation_enabled()) {
+ CompLevel next_osr_level = loop_event(imh(), level, thread);
+ CompLevel max_osr_level = (CompLevel)imh->highest_osr_comp_level();
+ // At the very least compile the OSR version
+ if (!CompileBroker::compilation_is_in_queue(imh) && (next_osr_level != level)) {
+ compile(imh, bci, next_osr_level, thread);
+ }
+
+ // Use loop event as an opportunity to also check if there's been
+ // enough calls.
+ CompLevel cur_level, next_level;
+ if (mh() != imh()) { // If there is an enclosing method
+ if (level == CompLevel_aot) {
+ // Recompile the enclosing method to prevent infinite OSRs. Stay at AOT level while it's compiling.
+ if (max_osr_level != CompLevel_none && !CompileBroker::compilation_is_in_queue(mh)) {
+ compile(mh, InvocationEntryBci, MIN2((CompLevel)TieredStopAtLevel, CompLevel_full_profile), thread);
+ }
+ } else {
+ // Current loop event level is not AOT
+ guarantee(nm != NULL, "Should have nmethod here");
+ cur_level = comp_level(mh());
+ next_level = call_event(mh(), cur_level, thread);
+
+ if (max_osr_level == CompLevel_full_optimization) {
+ // The inlinee OSRed to full opt, we need to modify the enclosing method to avoid deopts
+ bool make_not_entrant = false;
+ if (nm->is_osr_method()) {
+ // This is an osr method, just make it not entrant and recompile later if needed
+ make_not_entrant = true;
+ } else {
+ if (next_level != CompLevel_full_optimization) {
+ // next_level is not full opt, so we need to recompile the
+ // enclosing method without the inlinee
+ cur_level = CompLevel_none;
+ make_not_entrant = true;
+ }
+ }
+ if (make_not_entrant) {
+ if (PrintTieredEvents) {
+ int osr_bci = nm->is_osr_method() ? nm->osr_entry_bci() : InvocationEntryBci;
+ print_event(MAKE_NOT_ENTRANT, mh(), mh(), osr_bci, level);
+ }
+ nm->make_not_entrant();
+ }
+ }
+ // Fix up next_level if necessary to avoid deopts
+ if (next_level == CompLevel_limited_profile && max_osr_level == CompLevel_full_profile) {
+ next_level = CompLevel_full_profile;
+ }
+ if (cur_level != next_level) {
+ if (!maybe_switch_to_aot(mh, cur_level, next_level, thread) && !CompileBroker::compilation_is_in_queue(mh)) {
+ compile(mh, InvocationEntryBci, next_level, thread);
+ }
+ }
+ }
+ } else {
+ cur_level = comp_level(mh());
+ next_level = call_event(mh(), cur_level, thread);
+ if (next_level != cur_level) {
+ if (!maybe_switch_to_aot(mh, cur_level, next_level, thread) && !CompileBroker::compilation_is_in_queue(mh)) {
+ compile(mh, InvocationEntryBci, next_level, thread);
+ }
+ }
+ }
+ }
+}
+
+#endif