Reviewers: Jakob,
Message:
Please take a look.
Description:
Re-enable optimization for hot functions that have optimization disabled
due to
many deopts.
Use exponential backoff in order to avoid getting into
optimization-deoptimization cycle.
BUG=v8:2040,121196
Please review this at http://codereview.chromium.org/10202007/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files:
M src/heap.cc
M src/objects-inl.h
M src/objects.h
M src/objects.cc
M src/runtime-profiler.cc
Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index
90810170a6e3f26c4c015981f7119db6e226cf1c..dce346e09391ce94de7346230ed760a8d22afc91
100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -3010,7 +3010,6 @@ MaybeObject* Heap::AllocateSharedFunctionInfo(Object*
name) {
share->set_this_property_assignments(undefined_value(),
SKIP_WRITE_BARRIER);
share->set_ast_node_count(0);
share->set_deopt_counter(FLAG_deopt_every_n_times);
- share->set_ic_age(0);
// Set integer fields (smi or int, depending on the architecture).
share->set_length(0);
@@ -3024,6 +3023,8 @@ MaybeObject* Heap::AllocateSharedFunctionInfo(Object*
name) {
share->set_compiler_hints(0);
share->set_this_property_assignments_count(0);
share->set_opt_count(0);
+ share->set_ic_age(0);
+ share->set_opt_reenable_tries(0);
return share;
}
Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index
677d567b7a323441078714b02ebc87c18864b404..104c24ea8642dbf66971f2f2c42dfb794c9f121c
100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -3511,7 +3511,6 @@ ACCESSORS(SharedFunctionInfo, debug_info, Object,
kDebugInfoOffset)
ACCESSORS(SharedFunctionInfo, inferred_name, String, kInferredNameOffset)
ACCESSORS(SharedFunctionInfo, this_property_assignments, Object,
kThisPropertyAssignmentsOffset)
-SMI_ACCESSORS(SharedFunctionInfo, ic_age, kICAgeOffset)
BOOL_ACCESSORS(FunctionTemplateInfo, flag, hidden_prototype,
@@ -3562,6 +3561,8 @@ SMI_ACCESSORS(SharedFunctionInfo,
this_property_assignments_count,
SMI_ACCESSORS(SharedFunctionInfo, opt_count, kOptCountOffset)
SMI_ACCESSORS(SharedFunctionInfo, ast_node_count, kAstNodeCountOffset)
SMI_ACCESSORS(SharedFunctionInfo, deopt_counter, kDeoptCounterOffset)
+SMI_ACCESSORS(SharedFunctionInfo, ic_age, kICAgeOffset)
+SMI_ACCESSORS(SharedFunctionInfo, opt_reenable_tries,
kOptReenableTriesOffset)
#else
#define PSEUDO_SMI_ACCESSORS_LO(holder, name, offset) \
@@ -3615,6 +3616,11 @@ PSEUDO_SMI_ACCESSORS_HI(SharedFunctionInfo,
opt_count, kOptCountOffset)
PSEUDO_SMI_ACCESSORS_LO(SharedFunctionInfo, ast_node_count,
kAstNodeCountOffset)
PSEUDO_SMI_ACCESSORS_HI(SharedFunctionInfo, deopt_counter,
kDeoptCounterOffset)
+
+PSEUDO_SMI_ACCESSORS_LO(SharedFunctionInfo, ic_age, kICAgeOffset)
+PSEUDO_SMI_ACCESSORS_HI(SharedFunctionInfo,
+ opt_reenable_tries,
+ kOptReenableTriesOffset)
#endif
@@ -3654,6 +3660,7 @@ void
SharedFunctionInfo::set_optimization_disabled(bool disable) {
// it will not be counted as optimizable code.
if ((code()->kind() == Code::FUNCTION) && disable) {
code()->set_optimizable(false);
+ code()->set_profiler_ticks(0);
}
}
@@ -3689,6 +3696,23 @@ bool SharedFunctionInfo::is_classic_mode() {
return !BooleanBit::get(compiler_hints(), kStrictModeFunction);
}
+
+void SharedFunctionInfo::TryReenableOptimization() {
+ int tries = opt_reenable_tries();
+ if (tries == Smi::kMaxValue) {
+ tries = 0;
+ }
+ set_opt_reenable_tries(tries + 1);
+ // We reenable optimization whenever the number of tries is a large
+ // enough power of 2.
+ if (tries > 4 && (((tries - 1) & tries) == 0)) {
+ set_optimization_disabled(false);
+ set_opt_count(0);
+ code()->set_optimizable(true);
+ }
+}
+
+
BOOL_GETTER(SharedFunctionInfo, compiler_hints, is_extended_mode,
kExtendedModeFunction)
BOOL_ACCESSORS(SharedFunctionInfo, compiler_hints, native, kNative)
Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index
ef9d498b6dbe86914de86d916c593f2a4a4dd079..41f2ab6d8823f2e85ee1ec636e0016a495273fa6
100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -7871,6 +7871,7 @@ void SharedFunctionInfo::ResetForNewContext(int
new_ic_age) {
code()->set_optimizable(true);
}
set_opt_count(0);
+ set_opt_reenable_tries(0);
}
}
Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index
80d1fd47d02ab60dd015704d7836b20bf9b9189a..030e70f81cad1b0c54aa2a555957e187815f394c
100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -5461,6 +5461,13 @@ class SharedFunctionInfo: public HeapObject {
inline int opt_count();
inline void set_opt_count(int opt_count);
+ // Number of times we tried to reenable optimization.
+ inline int opt_reenable_tries();
+ inline void set_opt_reenable_tries(int opt_reenable_tries);
+
+ inline void TryReenableOptimization();
+
+
// Source size of this function.
int SourceSize();
@@ -5517,13 +5524,10 @@ class SharedFunctionInfo: public HeapObject {
kInferredNameOffset + kPointerSize;
static const int kThisPropertyAssignmentsOffset =
kInitialMapOffset + kPointerSize;
- // ic_age is a Smi field. It could be grouped with another Smi field
into a
- // PSEUDO_SMI_ACCESSORS pair (on x64), if one becomes available.
- static const int kICAgeOffset = kThisPropertyAssignmentsOffset +
kPointerSize;
#if V8_HOST_ARCH_32_BIT
// Smi fields.
static const int kLengthOffset =
- kICAgeOffset + kPointerSize;
+ kThisPropertyAssignmentsOffset + kPointerSize;
static const int kFormalParameterCountOffset = kLengthOffset +
kPointerSize;
static const int kExpectedNofPropertiesOffset =
kFormalParameterCountOffset + kPointerSize;
@@ -5543,10 +5547,10 @@ class SharedFunctionInfo: public HeapObject {
kThisPropertyAssignmentsCountOffset + kPointerSize;
static const int kAstNodeCountOffset = kOptCountOffset + kPointerSize;
static const int kDeoptCounterOffset = kAstNodeCountOffset +
kPointerSize;
-
-
+ static const int kICAgeOffset = kDeoptCounterOffset + kPointerSize;
+ static const int kOptReenableTriesOffset = kICAgeOffset + kPointerSize;
// Total size.
- static const int kSize = kDeoptCounterOffset + kPointerSize;
+ static const int kSize = kOptReenableTriesOffset + kPointerSize;
#else
// The only reason to use smi fields instead of int fields
// is to allow iteration without maps decoding during
@@ -5585,8 +5589,11 @@ class SharedFunctionInfo: public HeapObject {
static const int kAstNodeCountOffset = kOptCountOffset + kIntSize;
static const int kDeoptCounterOffset = kAstNodeCountOffset + kIntSize;
+ static const int kICAgeOffset = kDeoptCounterOffset + kIntSize;
+ static const int kOptReenableTriesOffset = kICAgeOffset + kIntSize;
+
// Total size.
- static const int kSize = kDeoptCounterOffset + kIntSize;
+ static const int kSize = kOptReenableTriesOffset + kIntSize;
#endif
Index: src/runtime-profiler.cc
diff --git a/src/runtime-profiler.cc b/src/runtime-profiler.cc
index
568e48e412c03f4151f6fb9ae30323efd0a0182b..33481d45b9ab607f59fde6dd4c3e078de7cec507
100644
--- a/src/runtime-profiler.cc
+++ b/src/runtime-profiler.cc
@@ -65,11 +65,17 @@ static const int kSizeLimit = 1500;
// 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
@@ -263,7 +269,8 @@ void RuntimeProfiler::OptimizeNow() {
}
}
- 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()) {
@@ -273,19 +280,31 @@ void RuntimeProfiler::OptimizeNow() {
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();
@@ -309,7 +328,7 @@ void RuntimeProfiler::OptimizeNow() {
}
}
} 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");
@@ -319,7 +338,7 @@ void RuntimeProfiler::OptimizeNow() {
} 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;
--
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