Line data Source code
1 : // Copyright 2012 the V8 project authors. All rights reserved.
2 : // Use of this source code is governed by a BSD-style license that can be
3 : // found in the LICENSE file.
4 :
5 : #include "src/runtime-profiler.h"
6 :
7 : #include "src/assembler.h"
8 : #include "src/base/platform/platform.h"
9 : #include "src/bootstrapper.h"
10 : #include "src/compilation-cache.h"
11 : #include "src/compiler.h"
12 : #include "src/execution.h"
13 : #include "src/frames-inl.h"
14 : #include "src/global-handles.h"
15 : #include "src/interpreter/interpreter.h"
16 : #include "src/tracing/trace-event.h"
17 :
18 : namespace v8 {
19 : namespace internal {
20 :
21 : // Number of times a function has to be seen on the stack before it is
22 : // optimized.
23 : static const int kProfilerTicksBeforeOptimization = 2;
24 :
25 : // The number of ticks required for optimizing a function increases with
26 : // the size of the bytecode. This is in addition to the
27 : // kProfilerTicksBeforeOptimization required for any function.
28 : static const int kBytecodeSizeAllowancePerTick = 1200;
29 :
30 : // Maximum size in bytes of generate code for a function to allow OSR.
31 : static const int kOSRBytecodeSizeAllowanceBase = 180;
32 :
33 : static const int kOSRBytecodeSizeAllowancePerTick = 48;
34 :
35 : // Maximum size in bytes of generated code for a function to be optimized
36 : // the very first time it is seen on the stack.
37 : static const int kMaxBytecodeSizeForEarlyOpt = 90;
38 :
39 : #define OPTIMIZATION_REASON_LIST(V) \
40 : V(DoNotOptimize, "do not optimize") \
41 : V(HotAndStable, "hot and stable") \
42 : V(SmallFunction, "small function")
43 :
44 : enum class OptimizationReason : uint8_t {
45 : #define OPTIMIZATION_REASON_CONSTANTS(Constant, message) k##Constant,
46 : OPTIMIZATION_REASON_LIST(OPTIMIZATION_REASON_CONSTANTS)
47 : #undef OPTIMIZATION_REASON_CONSTANTS
48 : };
49 :
50 0 : char const* OptimizationReasonToString(OptimizationReason reason) {
51 : static char const* reasons[] = {
52 : #define OPTIMIZATION_REASON_TEXTS(Constant, message) message,
53 : OPTIMIZATION_REASON_LIST(OPTIMIZATION_REASON_TEXTS)
54 : #undef OPTIMIZATION_REASON_TEXTS
55 : };
56 28646 : size_t const index = static_cast<size_t>(reason);
57 : DCHECK_LT(index, arraysize(reasons));
58 28646 : return reasons[index];
59 : }
60 :
61 0 : std::ostream& operator<<(std::ostream& os, OptimizationReason reason) {
62 0 : return os << OptimizationReasonToString(reason);
63 : }
64 :
65 62425 : RuntimeProfiler::RuntimeProfiler(Isolate* isolate)
66 : : isolate_(isolate),
67 62425 : any_ic_changed_(false) {
68 62425 : }
69 :
70 28646 : static void TraceRecompile(JSFunction function, const char* reason,
71 : const char* type) {
72 28646 : if (FLAG_trace_opt) {
73 1 : PrintF("[marking ");
74 1 : function->ShortPrint();
75 1 : PrintF(" for %s recompilation, reason: %s", type, reason);
76 1 : PrintF("]\n");
77 : }
78 28646 : }
79 :
80 0 : void RuntimeProfiler::Optimize(JSFunction function, OptimizationReason reason) {
81 : DCHECK_NE(reason, OptimizationReason::kDoNotOptimize);
82 28646 : TraceRecompile(function, OptimizationReasonToString(reason), "optimized");
83 28646 : function->MarkForOptimization(ConcurrencyMode::kConcurrent);
84 0 : }
85 :
86 35281 : void RuntimeProfiler::AttemptOnStackReplacement(InterpretedFrame* frame,
87 : int loop_nesting_levels) {
88 35281 : JSFunction function = frame->function();
89 35281 : SharedFunctionInfo shared = function->shared();
90 35281 : if (!FLAG_use_osr || !shared->IsUserJavaScript()) {
91 4774 : return;
92 : }
93 :
94 : // If the code is not optimizable, don't try OSR.
95 33802 : if (shared->optimization_disabled()) return;
96 :
97 : // We're using on-stack replacement: Store new loop nesting level in
98 : // BytecodeArray header so that certain back edges in any interpreter frame
99 : // for this bytecode will trigger on-stack replacement for that frame.
100 30507 : if (FLAG_trace_osr) {
101 0 : PrintF("[OSR - arming back edges in ");
102 0 : function->PrintName();
103 0 : PrintF("]\n");
104 : }
105 :
106 : DCHECK_EQ(StackFrame::INTERPRETED, frame->type());
107 61014 : int level = frame->GetBytecodeArray()->osr_loop_nesting_level();
108 91521 : frame->GetBytecodeArray()->set_osr_loop_nesting_level(
109 : Min(level + loop_nesting_levels, AbstractCode::kMaxLoopNestingMarker));
110 : }
111 :
112 164576 : void RuntimeProfiler::MaybeOptimize(JSFunction function,
113 : InterpretedFrame* frame) {
114 164576 : if (function->IsInOptimizationQueue()) {
115 3782 : if (FLAG_trace_opt_verbose) {
116 0 : PrintF("[function ");
117 0 : function->PrintName();
118 0 : PrintF(" is already in optimization queue]\n");
119 : }
120 : return;
121 : }
122 :
123 160794 : if (FLAG_always_osr) {
124 0 : AttemptOnStackReplacement(frame, AbstractCode::kMaxLoopNestingMarker);
125 : // Fall through and do a normal optimized compile as well.
126 160794 : } else if (MaybeOSR(function, frame)) {
127 : return;
128 : }
129 :
130 121167 : if (function->shared()->optimization_disabled()) return;
131 :
132 : OptimizationReason reason =
133 66205 : ShouldOptimize(function, function->shared()->GetBytecodeArray());
134 :
135 66205 : if (reason != OptimizationReason::kDoNotOptimize) {
136 : Optimize(function, reason);
137 : }
138 : }
139 :
140 160794 : bool RuntimeProfiler::MaybeOSR(JSFunction function, InterpretedFrame* frame) {
141 : int ticks = function->feedback_vector()->profiler_ticks();
142 : // TODO(rmcilroy): Also ensure we only OSR top-level code if it is smaller
143 : // than kMaxToplevelSourceSize.
144 :
145 480814 : if (function->IsMarkedForOptimization() ||
146 284867 : function->IsMarkedForConcurrentOptimization() ||
147 124073 : function->HasOptimizedCode()) {
148 : // Attempt OSR if we are still running interpreted code even though the
149 : // the function has long been marked or even already been optimized.
150 : int64_t allowance =
151 : kOSRBytecodeSizeAllowanceBase +
152 39627 : static_cast<int64_t>(ticks) * kOSRBytecodeSizeAllowancePerTick;
153 79254 : if (function->shared()->GetBytecodeArray()->length() <= allowance) {
154 28676 : AttemptOnStackReplacement(frame);
155 : }
156 : return true;
157 : }
158 : return false;
159 : }
160 :
161 66205 : OptimizationReason RuntimeProfiler::ShouldOptimize(JSFunction function,
162 : BytecodeArray bytecode) {
163 : int ticks = function->feedback_vector()->profiler_ticks();
164 : int ticks_for_optimization =
165 : kProfilerTicksBeforeOptimization +
166 66205 : (bytecode->length() / kBytecodeSizeAllowancePerTick);
167 66205 : if (ticks >= ticks_for_optimization) {
168 : return OptimizationReason::kHotAndStable;
169 53017 : } else if (!any_ic_changed_ &&
170 : bytecode->length() < kMaxBytecodeSizeForEarlyOpt) {
171 : // If no IC was patched since the last tick and this function is very
172 : // small, optimistically optimize it now.
173 : return OptimizationReason::kSmallFunction;
174 37559 : } else if (FLAG_trace_opt_verbose) {
175 0 : PrintF("[not yet optimizing ");
176 0 : function->PrintName();
177 : PrintF(", not enough ticks: %d/%d and ", ticks,
178 0 : kProfilerTicksBeforeOptimization);
179 0 : if (any_ic_changed_) {
180 0 : PrintF("ICs changed]\n");
181 : } else {
182 : PrintF(" too large for small function optimization: %d/%d]\n",
183 0 : bytecode->length(), kMaxBytecodeSizeForEarlyOpt);
184 : }
185 : }
186 : return OptimizationReason::kDoNotOptimize;
187 : }
188 :
189 1621547 : void RuntimeProfiler::MarkCandidatesForOptimization() {
190 1621547 : HandleScope scope(isolate_);
191 :
192 1621547 : if (!isolate_->use_optimizer()) return;
193 :
194 : DisallowHeapAllocation no_gc;
195 517914 : TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.compile"),
196 : "V8.MarkCandidatesForOptimization");
197 :
198 : // Run through the JavaScript frames and collect them. If we already
199 : // have a sample of the function, we mark it for optimizations
200 : // (eagerly or lazily).
201 : int frame_count = 0;
202 172638 : int frame_count_limit = FLAG_frame_count;
203 690536 : for (JavaScriptFrameIterator it(isolate_);
204 345268 : frame_count++ < frame_count_limit && !it.done();
205 172630 : it.Advance()) {
206 : JavaScriptFrame* frame = it.frame();
207 353314 : if (!frame->is_interpreted()) continue;
208 :
209 164576 : JSFunction function = frame->function();
210 : DCHECK(function->shared()->is_compiled());
211 329152 : if (!function->shared()->IsInterpreted()) continue;
212 :
213 164576 : if (!function->has_feedback_vector()) continue;
214 :
215 164576 : MaybeOptimize(function, InterpretedFrame::cast(frame));
216 :
217 : // TODO(leszeks): Move this increment to before the maybe optimize checks,
218 : // and update the tests to assume the increment has already happened.
219 : int ticks = function->feedback_vector()->profiler_ticks();
220 164576 : if (ticks < Smi::kMaxValue) {
221 164576 : function->feedback_vector()->set_profiler_ticks(ticks + 1);
222 : }
223 : }
224 172638 : any_ic_changed_ = false;
225 : }
226 :
227 : } // namespace internal
228 122004 : } // namespace v8
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