[Turbofan] don't optimize from bytecode > 250K in size.

src/runtime-profiler.cc

Index: src/runtime-profiler.cc
diff --git a/src/runtime-profiler.cc b/src/runtime-profiler.cc
index 70c61b1cebe5ded8306ad58bce21bdb13c18d2cf..f5b102556016d802cccbfc44a8ddfc74967a8f3f 100644
--- a/src/runtime-profiler.cc
+++ b/src/runtime-profiler.cc
@@ -57,6 +57,9 @@ static const int kMaxSizeEarlyOpt =
 static const int kMaxSizeEarlyOptIgnition =
     5 * interpreter::Interpreter::kCodeSizeMultiplier;
 
+// Certain functions are simply too big to be worth optimizing.
+static const int kMaxSizeOptFromBytecode = 250 * 1024;

[Michael Starzinger, 2017/01/30 12:42:11]

nit: Can we call this "kMaxSizeOptIgnition" to follow the same naming convention
as the above constants. Also, it might make sense to mention that the only
reason this is not based on kCodeSizeMultiplier is because there is no such
heuristic for optimization of baseline frames (i.e. no kMaxSizeOpt).

[mvstanton, 2017/01/30 14:55:37]

"We are not using the code size multiplier here because there is no
"kMaxSizeOpt" with which we would need to normalize."

Better name: kMaxSizeOptIgnition.


Done.

+
 #define OPTIMIZATION_REASON_LIST(V)                            \
   V(DoNotOptimize, "do not optimize")                          \
   V(HotAndStable, "hot and stable")                            \
@@ -394,6 +397,10 @@ OptimizationReason RuntimeProfiler::ShouldOptimizeIgnition(
   SharedFunctionInfo* shared = function->shared();
   int ticks = shared->profiler_ticks();
 
+  if (shared->bytecode_array()->Size() > kMaxSizeOptFromBytecode) {

[Michael Starzinger, 2017/01/30 12:42:11]

nit: s/Size/instruction_size/ to avoid dispatched getter and for readability and
to keep it in sync with the other heuristics in this file that are based on
"bytecode" size.

[Michael Starzinger, 2017/01/30 12:54:48]

Ooops, looked at the wrong use-site. Please disregard. Sorry for the noise.

[mvstanton, 2017/01/30 14:55:37]

Per discussion, Size() is now the right predicate.

+    return OptimizationReason::kDoNotOptimize;
+  }
+
   if (ticks >= kProfilerTicksBeforeOptimization) {
     int typeinfo, generic, total, type_percentage, generic_percentage;
     GetICCounts(function, &typeinfo, &generic, &total, &type_percentage,