blob: 58cf706d0c23c5fbcfaabd097c81659a0f3d18a0 [file] [log] [blame]
// 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"
#include "src/compilation-cache.h"
#include "src/compiler.h"
#include "src/execution.h"
#include "src/frames-inl.h"
#include "src/global-handles.h"
#include "src/interpreter/interpreter.h"
namespace v8 {
namespace internal {
// Number of times a function has to be seen on the stack before it is
// optimized.
static const int kProfilerTicksBeforeOptimization = 2;
// The number of ticks required for optimizing a function increases with
// the size of the bytecode. This is in addition to the
// kProfilerTicksBeforeOptimization required for any function.
static const int kBytecodeSizeAllowancePerTick = 1200;
// Maximum size in bytes of generate code for a function to allow OSR.
static const int kOSRBytecodeSizeAllowanceBase = 180;
static const int kOSRBytecodeSizeAllowancePerTick = 48;
// 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 kMaxBytecodeSizeForEarlyOpt = 90;
// Certain functions are simply too big to be worth optimizing.
static const int kMaxBytecodeSizeForOpt = 60 * KB;
#define OPTIMIZATION_REASON_LIST(V) \
V(DoNotOptimize, "do not optimize") \
V(HotAndStable, "hot and stable") \
V(SmallFunction, "small function")
enum class OptimizationReason : uint8_t {
#define OPTIMIZATION_REASON_CONSTANTS(Constant, message) k##Constant,
OPTIMIZATION_REASON_LIST(OPTIMIZATION_REASON_CONSTANTS)
#undef OPTIMIZATION_REASON_CONSTANTS
};
char const* OptimizationReasonToString(OptimizationReason reason) {
static char const* reasons[] = {
#define OPTIMIZATION_REASON_TEXTS(Constant, message) message,
OPTIMIZATION_REASON_LIST(OPTIMIZATION_REASON_TEXTS)
#undef OPTIMIZATION_REASON_TEXTS
};
size_t const index = static_cast<size_t>(reason);
DCHECK_LT(index, arraysize(reasons));
return reasons[index];
}
std::ostream& operator<<(std::ostream& os, OptimizationReason reason) {
return os << OptimizationReasonToString(reason);
}
RuntimeProfiler::RuntimeProfiler(Isolate* isolate)
: isolate_(isolate),
any_ic_changed_(false) {
}
static void GetICCounts(JSFunction* function, int* ic_with_type_info_count,
int* ic_generic_count, int* ic_total_count,
int* type_info_percentage, int* generic_percentage) {
// Harvest vector-ics.
FeedbackVector* vector = function->feedback_vector();
vector->ComputeCounts(ic_with_type_info_count, ic_generic_count,
ic_total_count);
if (*ic_total_count > 0) {
*type_info_percentage = 100 * *ic_with_type_info_count / *ic_total_count;
*generic_percentage = 100 * *ic_generic_count / *ic_total_count;
} else {
*type_info_percentage = 100; // Compared against lower bound.
*generic_percentage = 0; // Compared against upper bound.
}
}
static void TraceRecompile(JSFunction* function, const char* reason,
const char* type) {
if (FLAG_trace_opt) {
PrintF("[marking ");
function->ShortPrint();
PrintF(" for %s recompilation, reason: %s", type, reason);
if (FLAG_type_info_threshold > 0) {
int typeinfo, generic, total, type_percentage, generic_percentage;
GetICCounts(function, &typeinfo, &generic, &total, &type_percentage,
&generic_percentage);
PrintF(", ICs with typeinfo: %d/%d (%d%%)", typeinfo, total,
type_percentage);
PrintF(", generic ICs: %d/%d (%d%%)", generic, total, generic_percentage);
}
PrintF("]\n");
}
}
void RuntimeProfiler::Optimize(JSFunction* function,
OptimizationReason reason) {
DCHECK_NE(reason, OptimizationReason::kDoNotOptimize);
TraceRecompile(function, OptimizationReasonToString(reason), "optimized");
function->MarkForOptimization(ConcurrencyMode::kConcurrent);
}
void RuntimeProfiler::AttemptOnStackReplacement(JavaScriptFrame* frame,
int loop_nesting_levels) {
JSFunction* function = frame->function();
SharedFunctionInfo* shared = function->shared();
if (!FLAG_use_osr || !function->shared()->IsUserJavaScript()) {
return;
}
// If the code is not optimizable, don't try OSR.
if (shared->optimization_disabled()) return;
// We're using on-stack replacement: Store new loop nesting level in
// BytecodeArray header so that certain back edges in any interpreter frame
// for this bytecode will trigger on-stack replacement for that frame.
if (FLAG_trace_osr) {
PrintF("[OSR - arming back edges in ");
function->PrintName();
PrintF("]\n");
}
DCHECK_EQ(StackFrame::INTERPRETED, frame->type());
DCHECK(shared->HasBytecodeArray());
int level = shared->bytecode_array()->osr_loop_nesting_level();
shared->bytecode_array()->set_osr_loop_nesting_level(
Min(level + loop_nesting_levels, AbstractCode::kMaxLoopNestingMarker));
}
void RuntimeProfiler::MaybeOptimize(JSFunction* function,
JavaScriptFrame* frame) {
if (function->IsInOptimizationQueue()) {
if (FLAG_trace_opt_verbose) {
PrintF("[function ");
function->PrintName();
PrintF(" is already in optimization queue]\n");
}
return;
}
if (FLAG_always_osr) {
AttemptOnStackReplacement(frame, AbstractCode::kMaxLoopNestingMarker);
// Fall through and do a normal optimized compile as well.
} else if (MaybeOSR(function, frame)) {
return;
}
if (function->shared()->optimization_disabled()) return;
if (frame->is_optimized()) return;
OptimizationReason reason = ShouldOptimize(function, frame);
if (reason != OptimizationReason::kDoNotOptimize) {
Optimize(function, reason);
}
}
bool RuntimeProfiler::MaybeOSR(JSFunction* function, JavaScriptFrame* frame) {
SharedFunctionInfo* shared = function->shared();
int ticks = function->feedback_vector()->profiler_ticks();
// TODO(rmcilroy): Also ensure we only OSR top-level code if it is smaller
// than kMaxToplevelSourceSize.
if (!frame->is_optimized() &&
(function->IsMarkedForOptimization() ||
function->IsMarkedForConcurrentOptimization() ||
function->HasOptimizedCode())) {
// Attempt OSR if we are still running interpreted code even though the
// the function has long been marked or even already been optimized.
int64_t allowance =
kOSRBytecodeSizeAllowanceBase +
static_cast<int64_t>(ticks) * kOSRBytecodeSizeAllowancePerTick;
if (shared->bytecode_array()->length() <= allowance) {
AttemptOnStackReplacement(frame);
}
return true;
}
return false;
}
OptimizationReason RuntimeProfiler::ShouldOptimize(JSFunction* function,
JavaScriptFrame* frame) {
SharedFunctionInfo* shared = function->shared();
int ticks = function->feedback_vector()->profiler_ticks();
if (shared->bytecode_array()->length() > kMaxBytecodeSizeForOpt) {
return OptimizationReason::kDoNotOptimize;
}
int ticks_for_optimization =
kProfilerTicksBeforeOptimization +
(shared->bytecode_array()->length() / kBytecodeSizeAllowancePerTick);
if (ticks >= ticks_for_optimization) {
return OptimizationReason::kHotAndStable;
} else if (!any_ic_changed_ &&
shared->bytecode_array()->length() < kMaxBytecodeSizeForEarlyOpt) {
// If no IC was patched since the last tick and this function is very
// small, optimistically optimize it now.
return OptimizationReason::kSmallFunction;
} else if (FLAG_trace_opt_verbose) {
PrintF("[not yet optimizing ");
function->PrintName();
PrintF(", not enough ticks: %d/%d and ", ticks,
kProfilerTicksBeforeOptimization);
if (any_ic_changed_) {
PrintF("ICs changed]\n");
} else {
PrintF(" too large for small function optimization: %d/%d]\n",
shared->bytecode_array()->length(), kMaxBytecodeSizeForEarlyOpt);
}
}
return OptimizationReason::kDoNotOptimize;
}
void RuntimeProfiler::MarkCandidatesForOptimization() {
HandleScope scope(isolate_);
if (!isolate_->use_optimizer()) return;
DisallowHeapAllocation no_gc;
// Run through the JavaScript frames and collect them. If we already
// have a sample of the function, we mark it for optimizations
// (eagerly or lazily).
int frame_count = 0;
int frame_count_limit = FLAG_frame_count;
for (JavaScriptFrameIterator it(isolate_);
frame_count++ < frame_count_limit && !it.done();
it.Advance()) {
JavaScriptFrame* frame = it.frame();
if (frame->is_optimized()) continue;
JSFunction* function = frame->function();
DCHECK(function->shared()->is_compiled());
if (!function->shared()->IsInterpreted()) continue;
MaybeOptimize(function, frame);
// TODO(leszeks): Move this increment to before the maybe optimize checks,
// and update the tests to assume the increment has already happened.
int ticks = function->feedback_vector()->profiler_ticks();
if (ticks < Smi::kMaxValue) {
function->feedback_vector()->set_profiler_ticks(ticks + 1);
}
}
any_ic_changed_ = false;
}
} // namespace internal
} // namespace v8