Re-enable optimization for hot functions that have optimization disabled due to many deopts.

src/runtime-profiler.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 47 matching lines @@
 
 static const int kSamplerThresholdSizeFactorInit = 3;
 
 static const int kSizeLimit = 1500;
 
 // Constants for counter based profiler.
 
 // Number of times a function has to be seen on the stack before it is
 // optimized.
 static const int kProfilerTicksBeforeOptimization = 2;
+// If the function optimization was disabled due to high deoptimization count,
+// but the function is hot and has been seen on the stack this number of times,
+// then we try to reenable optimization for this function.
+static const int kProfilerTicksBeforeReenablingOptimization = 250;
 // If a function does not have enough type info (according to
 // FLAG_type_info_threshold), but has seen a huge number of ticks,
 // optimize it as it is.
 static const int kTicksWhenNotEnoughTypeInfo = 100;
 // We only have one byte to store the number of ticks.
+STATIC_ASSERT(kProfilerTicksBeforeOptimization < 256);
+STATIC_ASSERT(kProfilerTicksBeforeReenablingOptimization < 256);
 STATIC_ASSERT(kTicksWhenNotEnoughTypeInfo < 256);
 
 // Maximum size in bytes of generated code for a function to be optimized
 // the very first time it is seen on the stack.
 static const int kMaxSizeEarlyOpt = 500;
 
 
 Atomic32 RuntimeProfiler::state_ = 0;
 
 // TODO(isolates): Clean up the semaphore when it is no longer required.
@@ skipping 173 matching lines @@
           // modify and reset the ticks until next adjustment.
           if (sampler_threshold_ > kSamplerThresholdMin) {
             sampler_threshold_ -= kSamplerThresholdDelta;
             sampler_ticks_until_threshold_adjustment_ =
                 kSamplerTicksBetweenThresholdAdjustment;
           }
         }
       }
     }
 
-    Code* shared_code = function->shared()->code();
+    SharedFunctionInfo* shared = function->shared();
+    Code* shared_code = shared->code();
     if (shared_code->kind() != Code::FUNCTION) continue;
 
     if (function->IsMarkedForLazyRecompilation()) {
       int nesting = shared_code->allow_osr_at_loop_nesting_level();
       if (nesting == 0) AttemptOnStackReplacement(function);
       int new_nesting = Min(nesting + 1, Code::kMaxLoopNestingMarker);
       shared_code->set_allow_osr_at_loop_nesting_level(new_nesting);
     }
 
-    // Do not record non-optimizable functions.
-    if (!function->IsOptimizable()) continue;
-    if (function->shared()->optimization_disabled()) continue;
-
     // Only record top-level code on top of the execution stack and
     // avoid optimizing excessively large scripts since top-level code
     // will be executed only once.
     const int kMaxToplevelSourceSize = 10 * 1024;
-    if (function->shared()->is_toplevel()
-        && (frame_count > 1
-            || function->shared()->SourceSize() > kMaxToplevelSourceSize)) {
+    if (shared->is_toplevel() &&
+        (frame_count > 1 || shared->SourceSize() > kMaxToplevelSourceSize)) {
       continue;
     }
 
+    // Do not record non-optimizable functions.
+    if (shared->optimization_disabled()) {
+      if (shared->opt_count() >= Compiler::kDefaultMaxOptCount) {
+        // If optimization was disabled due to many deoptimizations,
+        // then check if the function is hot and try to reenable optimization.
+        int ticks = shared_code->profiler_ticks();
+        if (ticks >= kProfilerTicksBeforeReenablingOptimization) {
+          shared_code->set_profiler_ticks(0);
+          shared->TryReenableOptimization();
+        } else {
+          shared_code->set_profiler_ticks(ticks + 1);
+        }
+      }
+      continue;
+    }
+    if (!function->IsOptimizable()) continue;
+
     if (FLAG_watch_ic_patching) {
       int ticks = shared_code->profiler_ticks();
 
       if (ticks >= kProfilerTicksBeforeOptimization) {
         int typeinfo, total, percentage;
         GetICCounts(function, &typeinfo, &total, &percentage);
         if (percentage >= FLAG_type_info_threshold) {
           // If this particular function hasn't had any ICs patched for enough
           // ticks, optimize it now.
           Optimize(function, "hot and stable");
         } else if (ticks >= kTicksWhenNotEnoughTypeInfo) {
           Optimize(function, "not much type info but very hot");
         } else {
           shared_code->set_profiler_ticks(ticks + 1);
           if (FLAG_trace_opt_verbose) {
             PrintF("[not yet optimizing ");
             function->PrintName();
             PrintF(", not enough type info: %d/%d (%d%%)]\n",
                    typeinfo, total, percentage);
           }
         }
       } else if (!any_ic_changed_ &&
-          shared_code->instruction_size() < kMaxSizeEarlyOpt) {
+                 shared_code->instruction_size() < kMaxSizeEarlyOpt) {
         // If no IC was patched since the last tick and this function is very
         // small, optimistically optimize it now.
         Optimize(function, "small function");
       } else {
         shared_code->set_profiler_ticks(ticks + 1);
       }
     } else {  // !FLAG_watch_ic_patching
       samples[sample_count++] = function;
 
-      int function_size = function->shared()->SourceSize();
+      int function_size = shared->SourceSize();
       int threshold_size_factor = (function_size > kSizeLimit)
           ? sampler_threshold_size_factor_
           : 1;
 
       int threshold = sampler_threshold_ * threshold_size_factor;
 
       if (LookupSample(function) >= threshold) {
         Optimize(function, "sampler window lookup");
       }
     }
@@ skipping 131 matching lines @@
 
 bool RuntimeProfilerRateLimiter::SuspendIfNecessary() {
   if (!RuntimeProfiler::IsSomeIsolateInJS()) {
     return RuntimeProfiler::WaitForSomeIsolateToEnterJS();
   }
   return false;
 }
 
 
 } }  // namespace v8::internal