Mercurial > hg > graal-compiler
diff src/share/vm/runtime/advancedThresholdPolicy.cpp @ 2348:5d8f5a6dced7
7020403: Add AdvancedCompilationPolicy for tiered
Summary: This implements adaptive tiered compilation policy.
Reviewed-by: kvn, never
author | iveresov |
---|---|
date | Fri, 04 Mar 2011 15:14:16 -0800 |
parents | |
children | 97b64f73103b |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/runtime/advancedThresholdPolicy.cpp Fri Mar 04 15:14:16 2011 -0800 @@ -0,0 +1,450 @@ +/* +* 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