--- /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