[interpreter] Also optimize small functions earlier.

src/runtime-profiler.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/runtime-profiler.h"
 
 #include "src/assembler.h"
 #include "src/base/platform/platform.h"
 #include "src/bootstrapper.h"
 #include "src/code-stubs.h"
@@ skipping 36 matching lines @@
 
 static const int kOSRCodeSizeAllowancePerTick =
     4 * FullCodeGenerator::kCodeSizeMultiplier;
 static const int kOSRCodeSizeAllowancePerTickIgnition =
     4 * interpreter::Interpreter::kCodeSizeMultiplier;
 
 // 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 =
     5 * FullCodeGenerator::kCodeSizeMultiplier;
+static const int kMaxSizeEarlyOptIgnition =
+    5 * interpreter::Interpreter::kCodeSizeMultiplier;
 
 #define OPTIMIZATION_REASON_LIST(V)                            \
   V(DoNotOptimize, "do not optimize")                          \
   V(HotAndStable, "hot and stable")                            \
   V(HotEnoughForBaseline, "hot enough for baseline")           \
   V(HotWithoutMuchTypeInfo, "not much type info but very hot") \
   V(SmallFunction, "small function")
 
 enum class OptimizationReason : uint8_t {
 #define OPTIMIZATION_REASON_CONSTANTS(Constant, message) k##Constant,
@@ skipping 348 matching lines @@
       return OptimizationReason::kHotWithoutMuchTypeInfo;
     } else {
       if (FLAG_trace_opt_verbose) {
         PrintF("[not yet optimizing ");
         function->PrintName();
         PrintF(", not enough type info: %d/%d (%d%%)]\n", typeinfo, total,
                type_percentage);
       }
       return OptimizationReason::kDoNotOptimize;
     }
+  } else if (!any_ic_changed_ &&
+             shared->bytecode_array()->Size() < kMaxSizeEarlyOptIgnition) {
+    // If no IC was patched since the last tick and this function is very

[mythria, 2016/10/19 13:17:29]

Just for my understanding, any_ic_changed_ means if the feedback has changed
right? I am not sure if any changes in the Call feedback or binary op feedback
are Notified to runtime-profiler from ignition.  Would it be important to notify
these changes? If it is important should we add a TODO here?

[Benedikt Meurer, 2016/10/19 13:19:40]

That's a good point, I missed that. Can you put that on the agenda for your next
discussion with Ross?

+    // small, optimistically optimize it now.
+    int typeinfo, generic, total, type_percentage, generic_percentage;
+    GetICCounts(function, &typeinfo, &generic, &total, &type_percentage,
+                &generic_percentage);
+    if (type_percentage >= FLAG_type_info_threshold &&
+        generic_percentage <= FLAG_generic_ic_threshold) {
+      return OptimizationReason::kSmallFunction;
+    }
   }
-  // TODO(rmcilroy): Consider whether we should optimize small functions when
-  // they are first seen on the stack (e.g., kMaxSizeEarlyOpt).
   return OptimizationReason::kDoNotOptimize;
 }
 
 void RuntimeProfiler::MarkCandidatesForOptimization() {
   HandleScope scope(isolate_);
 
   if (!isolate_->use_crankshaft()) return;
 
   DisallowHeapAllocation no_gc;
 
@@ skipping 30 matching lines @@
     } else {
       DCHECK_EQ(next_tier, Compiler::OPTIMIZED);
       MaybeOptimizeFullCodegen(function, frame, frame_count);
     }
   }
   any_ic_changed_ = false;
 }
 
 }  // namespace internal
 }  // namespace v8