Mercurial > hg > graal-compiler
view src/share/vm/runtime/advancedThresholdPolicy.cpp @ 2455:479b4b4b6950
6777083: assert(target != __null,"must not be null")
Reviewed-by: iveresov, kvn
author | never |
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date | Tue, 05 Apr 2011 00:31:09 -0700 |
parents | 5d8f5a6dced7 |
children | 97b64f73103b |
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/* * Copyright (c) 2010, 2011 Oracle and/or its affiliates. All rights reserved. * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. */ #include "precompiled.hpp" #include "runtime/advancedThresholdPolicy.hpp" #include "runtime/simpleThresholdPolicy.inline.hpp" #ifdef TIERED // Print an event. void AdvancedThresholdPolicy::print_specific(EventType type, methodHandle mh, 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)); } void AdvancedThresholdPolicy::initialize() { // Turn on ergonomic compiler count selection if (FLAG_IS_DEFAULT(CICompilerCountPerCPU) && FLAG_IS_DEFAULT(CICompilerCount)) { FLAG_SET_DEFAULT(CICompilerCountPerCPU, true); } int count = CICompilerCount; 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, 1) * 3 / 2; } set_c1_count(MAX2(count / 3, 1)); set_c2_count(MAX2(count - count / 3, 1)); // Some inlining tuning #ifdef X86 if (FLAG_IS_DEFAULT(InlineSmallCode)) { FLAG_SET_DEFAULT(InlineSmallCode, 2000); } #endif #ifdef SPARC if (FLAG_IS_DEFAULT(InlineSmallCode)) { FLAG_SET_DEFAULT(InlineSmallCode, 2500); } #endif set_start_time(os::javaTimeMillis()); } // update_rate() is called from select_task() while holding a compile queue lock. void AdvancedThresholdPolicy::update_rate(jlong t, methodOop m) { 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 AdvancedThresholdPolicy::is_stale(jlong t, jlong timeout, methodOop 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 AdvancedThresholdPolicy::is_old(methodOop method) { return method->invocation_count() > 50000 || method->backedge_count() > 500000; } double AdvancedThresholdPolicy::weight(methodOop method) { return (method->rate() + 1) * ((method->invocation_count() + 1) * (method->backedge_count() + 1)); } // Apply heuristics and return true if x should be compiled before y bool AdvancedThresholdPolicy::compare_methods(methodOop x, methodOop 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 AdvancedThresholdPolicy::is_method_profiled(methodOop method) { methodDataOop 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); } return false; } // Called with the queue locked and with at least one element CompileTask* AdvancedThresholdPolicy::select_task(CompileQueue* compile_queue) { CompileTask *max_task = NULL; methodOop max_method; 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(); methodOop method = (methodOop)JNIHandles::resolve(task->method_handle()); methodDataOop mdo = method->method_data(); 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. if (is_stale(t, TieredCompileTaskTimeout, method) && !is_old(method)) { if (PrintTieredEvents) { print_event(KILL, method, method, task->osr_bci(), (CompLevel)task->comp_level()); } CompileTaskWrapper ctw(task); // Frees the task compile_queue->remove(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; } } task = next_task; } if (max_task->comp_level() == CompLevel_full_profile && is_method_profiled(max_method)) { max_task->set_comp_level(CompLevel_limited_profile); if (PrintTieredEvents) { print_event(UPDATE, max_method, max_method, max_task->osr_bci(), (CompLevel)max_task->comp_level()); } } return max_task; } double AdvancedThresholdPolicy::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; 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 AdvancedThresholdPolicy::loop_predicate(int i, int b, CompLevel cur_level) { switch(cur_level) { case CompLevel_none: case CompLevel_limited_profile: { double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback); return loop_predicate_helper<CompLevel_none>(i, b, k); } case CompLevel_full_profile: { double k = threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback); return loop_predicate_helper<CompLevel_full_profile>(i, b, k); } default: return true; } } bool AdvancedThresholdPolicy::call_predicate(int i, int b, CompLevel cur_level) { switch(cur_level) { case CompLevel_none: case CompLevel_limited_profile: { double k = threshold_scale(CompLevel_full_profile, Tier3LoadFeedback); return call_predicate_helper<CompLevel_none>(i, b, k); } case CompLevel_full_profile: { double k = threshold_scale(CompLevel_full_optimization, Tier4LoadFeedback); return call_predicate_helper<CompLevel_full_profile>(i, b, k); } default: return true; } } // 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 AdvancedThresholdPolicy::should_create_mdo(methodOop 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) || loop_predicate_helper<CompLevel_none>(i, b, k); } return false; } // Create MDO if necessary. void AdvancedThresholdPolicy::create_mdo(methodHandle mh, TRAPS) { if (mh->is_native() || mh->is_abstract() || mh->is_accessor()) return; if (mh->method_data() == NULL) { methodOopDesc::build_interpreter_method_data(mh, THREAD); if (HAS_PENDING_EXCEPTION) { CLEAR_PENDING_EXCEPTION; } } } /* * 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 occures 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, 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 AdvancedThresholdPolicy::common(Predicate p, methodOop method, CompLevel cur_level) { if (is_trivial(method)) return CompLevel_simple; CompLevel next_level = cur_level; int i = method->invocation_count(); int b = method->backedge_count(); switch(cur_level) { case CompLevel_none: // If we were at full profile level, would we switch to full opt? if (common(p, method, CompLevel_full_profile) == CompLevel_full_optimization) { next_level = CompLevel_full_optimization; } else if ((this->*p)(i, b, cur_level)) { // 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 (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 { methodDataOop mdo = method->method_data(); if (mdo != NULL) { if (mdo->would_profile()) { if (CompileBroker::queue_size(CompLevel_full_optimization) <= Tier3DelayOff * compiler_count(CompLevel_full_optimization) && (this->*p)(i, b, cur_level)) { next_level = CompLevel_full_profile; } } else { next_level = CompLevel_full_optimization; } } } break; case CompLevel_full_profile: { methodDataOop 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)) { next_level = CompLevel_full_optimization; } } else { next_level = CompLevel_full_optimization; } } } break; } return next_level; } // Determine if a method should be compiled with a normal entry point at a different level. CompLevel AdvancedThresholdPolicy::call_event(methodOop method, CompLevel cur_level) { CompLevel osr_level = (CompLevel) method->highest_osr_comp_level(); CompLevel next_level = common(&AdvancedThresholdPolicy::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) { methodDataOop 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); } return next_level; } // Determine if we should do an OSR compilation of a given method. CompLevel AdvancedThresholdPolicy::loop_event(methodOop method, CompLevel cur_level) { 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 = (CompLevel)method->highest_osr_comp_level(); if (osr_level > CompLevel_none) { return osr_level; } } return common(&AdvancedThresholdPolicy::loop_predicate, method, cur_level); } // Update the rate and submit compile void AdvancedThresholdPolicy::submit_compile(methodHandle mh, int bci, CompLevel level, TRAPS) { 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, "tiered", THREAD); } // Handle the invocation event. void AdvancedThresholdPolicy::method_invocation_event(methodHandle mh, methodHandle imh, CompLevel level, TRAPS) { if (should_create_mdo(mh(), level)) { create_mdo(mh, THREAD); } if (is_compilation_enabled() && !CompileBroker::compilation_is_in_queue(mh, InvocationEntryBci)) { CompLevel next_level = call_event(mh(), level); if (next_level != level) { 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 AdvancedThresholdPolicy::method_back_branch_event(methodHandle mh, methodHandle imh, int bci, CompLevel level, TRAPS) { if (should_create_mdo(mh(), level)) { create_mdo(mh, THREAD); } // If the method is already compiling, quickly bail out. if (is_compilation_enabled() && !CompileBroker::compilation_is_in_queue(mh, bci)) { // Use loop event as an opportinity to also check there's been // enough calls. CompLevel cur_level = comp_level(mh()); CompLevel next_level = call_event(mh(), cur_level); CompLevel next_osr_level = loop_event(mh(), level); if (next_osr_level == CompLevel_limited_profile) { next_osr_level = CompLevel_full_profile; // OSRs are supposed to be for very hot methods. } next_level = MAX2(next_level, next_osr_level < CompLevel_full_optimization ? next_osr_level : cur_level); bool is_compiling = false; if (next_level != cur_level) { compile(mh, InvocationEntryBci, next_level, THREAD); is_compiling = true; } // Do the OSR version if (!is_compiling && next_osr_level != level) { compile(mh, bci, next_osr_level, THREAD); } } } #endif // TIERED