Version 3.0.0.
Improved performance by (partially) addressing issue 957 on IA-32. Still needs more work for the other architectures.
git-svn-id: http://v8.googlecode.com/svn/trunk@5932 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
diff --git a/src/runtime-profiler.cc b/src/runtime-profiler.cc
new file mode 100644
index 0000000..051dc51
--- /dev/null
+++ b/src/runtime-profiler.cc
@@ -0,0 +1,385 @@
+// Copyright 2010 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following
+// disclaimer in the documentation and/or other materials provided
+// with the distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived
+// from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "v8.h"
+
+#include "runtime-profiler.h"
+
+#include "assembler.h"
+#include "code-stubs.h"
+#include "compilation-cache.h"
+#include "deoptimizer.h"
+#include "execution.h"
+#include "global-handles.h"
+#include "scopeinfo.h"
+#include "top.h"
+
+namespace v8 {
+namespace internal {
+
+
+class PendingListNode : public Malloced {
+ public:
+ explicit PendingListNode(JSFunction* function);
+ ~PendingListNode() { Destroy(); }
+
+ PendingListNode* next() const { return next_; }
+ void set_next(PendingListNode* node) { next_ = node; }
+ Handle<JSFunction> function() { return Handle<JSFunction>::cast(function_); }
+
+ // If the function is garbage collected before we've had the chance
+ // to optimize it the weak handle will be null.
+ bool IsValid() { return !function_.is_null(); }
+
+ // Returns the number of microseconds this node has been pending.
+ int Delay() const { return static_cast<int>(OS::Ticks() - start_); }
+
+ private:
+ void Destroy();
+ static void WeakCallback(v8::Persistent<v8::Value> object, void* data);
+
+ PendingListNode* next_;
+ Handle<Object> function_; // Weak handle.
+ int64_t start_;
+};
+
+
+// Optimization sampler constants.
+static const int kSamplerFrameCount = 2;
+static const int kSamplerFrameWeight[kSamplerFrameCount] = { 2, 1 };
+static const int kSamplerWindowSize = 16;
+
+static const int kSamplerTicksDelta = 32;
+
+static const int kSamplerThresholdInit = 3;
+static const int kSamplerThresholdMin = 1;
+static const int kSamplerThresholdDelta = 1;
+
+static const int kSamplerThresholdSizeFactorInit = 3;
+static const int kSamplerThresholdSizeFactorMin = 1;
+static const int kSamplerThresholdSizeFactorDelta = 1;
+
+static const int kSizeLimit = 1500;
+
+static int sampler_threshold = kSamplerThresholdInit;
+static int sampler_threshold_size_factor = kSamplerThresholdSizeFactorInit;
+
+
+// The JSFunctions in the sampler window are not GC safe. Old-space
+// pointers are not cleared during mark-sweep collection and therefore
+// the window might contain stale pointers. The window is updated on
+// scavenges and (parts of it) cleared on mark-sweep and
+// mark-sweep-compact.
+static Object* sampler_window[kSamplerWindowSize] = { NULL, };
+static int sampler_window_position = 0;
+static int sampler_window_weight[kSamplerWindowSize] = { 0, };
+
+
+// Support for pending 'optimize soon' requests.
+static PendingListNode* optimize_soon_list = NULL;
+
+
+PendingListNode::PendingListNode(JSFunction* function) : next_(NULL) {
+ function_ = GlobalHandles::Create(function);
+ start_ = OS::Ticks();
+ GlobalHandles::MakeWeak(function_.location(), this, &WeakCallback);
+}
+
+
+void PendingListNode::Destroy() {
+ if (!IsValid()) return;
+ GlobalHandles::Destroy(function_.location());
+ function_= Handle<Object>::null();
+}
+
+
+void PendingListNode::WeakCallback(v8::Persistent<v8::Value>, void* data) {
+ reinterpret_cast<PendingListNode*>(data)->Destroy();
+}
+
+
+static bool IsOptimizable(JSFunction* function) {
+ Code* code = function->code();
+ return code->kind() == Code::FUNCTION && code->optimizable();
+}
+
+
+static void Optimize(JSFunction* function, bool eager, int delay) {
+ ASSERT(IsOptimizable(function));
+ if (FLAG_trace_opt) {
+ PrintF("[marking (%s) ", eager ? "eagerly" : "lazily");
+ function->PrintName();
+ PrintF(" for recompilation");
+ if (delay > 0) {
+ PrintF(" (delayed %0.3f ms)", static_cast<double>(delay) / 1000);
+ }
+ PrintF("]\n");
+ }
+
+ // The next call to the function will trigger optimization.
+ function->MarkForLazyRecompilation();
+}
+
+
+static void AttemptOnStackReplacement(JSFunction* function) {
+ // See AlwaysFullCompiler (in compiler.cc) comment on why we need
+ // Debug::has_break_points().
+ ASSERT(function->IsMarkedForLazyRecompilation());
+ if (!FLAG_use_osr || Debug::has_break_points() || function->IsBuiltin()) {
+ return;
+ }
+
+ SharedFunctionInfo* shared = function->shared();
+ // If the code is not optimizable, don't try OSR.
+ if (!shared->code()->optimizable()) return;
+
+ // We are not prepared to do OSR for a function that already has an
+ // allocated arguments object. The optimized code would bypass it for
+ // arguments accesses, which is unsound. Don't try OSR.
+ if (shared->scope_info()->HasArgumentsShadow()) return;
+
+ // We're using on-stack replacement: patch the unoptimized code so that
+ // any back edge in any unoptimized frame will trigger on-stack
+ // replacement for that frame.
+ if (FLAG_trace_osr) {
+ PrintF("[patching stack checks in ");
+ function->PrintName();
+ PrintF(" for on-stack replacement]\n");
+ }
+
+ // Get the stack check stub code object to match against. We aren't
+ // prepared to generate it, but we don't expect to have to.
+ StackCheckStub check_stub;
+ Object* check_code;
+ MaybeObject* maybe_check_code = check_stub.TryGetCode();
+ if (maybe_check_code->ToObject(&check_code)) {
+ Code* replacement_code = Builtins::builtin(Builtins::OnStackReplacement);
+ Code* unoptimized_code = shared->code();
+ // Iterate the unoptimized code and patch every stack check except at
+ // the function entry. This code assumes the function entry stack
+ // check appears first i.e., is not deferred or otherwise reordered.
+ bool first = true;
+ for (RelocIterator it(unoptimized_code, RelocInfo::kCodeTargetMask);
+ !it.done();
+ it.next()) {
+ RelocInfo* rinfo = it.rinfo();
+ if (rinfo->target_address() == Code::cast(check_code)->entry()) {
+ if (first) {
+ first = false;
+ } else {
+ Deoptimizer::PatchStackCheckCode(rinfo, replacement_code);
+ }
+ }
+ }
+ }
+}
+
+
+static void ClearSampleBuffer() {
+ for (int i = 0; i < kSamplerWindowSize; i++) {
+ sampler_window[i] = NULL;
+ sampler_window_weight[i] = 0;
+ }
+}
+
+
+static void ClearSampleBufferNewSpaceEntries() {
+ for (int i = 0; i < kSamplerWindowSize; i++) {
+ if (Heap::InNewSpace(sampler_window[i])) {
+ sampler_window[i] = NULL;
+ sampler_window_weight[i] = 0;
+ }
+ }
+}
+
+
+static int LookupSample(JSFunction* function) {
+ int weight = 0;
+ for (int i = 0; i < kSamplerWindowSize; i++) {
+ Object* sample = sampler_window[i];
+ if (sample != NULL) {
+ if (function == sample) {
+ weight += sampler_window_weight[i];
+ }
+ }
+ }
+ return weight;
+}
+
+
+static void AddSample(JSFunction* function, int weight) {
+ ASSERT(IsPowerOf2(kSamplerWindowSize));
+ sampler_window[sampler_window_position] = function;
+ sampler_window_weight[sampler_window_position] = weight;
+ sampler_window_position = (sampler_window_position + 1) &
+ (kSamplerWindowSize - 1);
+}
+
+
+void RuntimeProfiler::OptimizeNow() {
+ HandleScope scope;
+ PendingListNode* current = optimize_soon_list;
+ while (current != NULL) {
+ PendingListNode* next = current->next();
+ if (current->IsValid()) {
+ Handle<JSFunction> function = current->function();
+ int delay = current->Delay();
+ if (IsOptimizable(*function)) {
+ Optimize(*function, true, delay);
+ }
+ }
+ delete current;
+ current = next;
+ }
+ optimize_soon_list = NULL;
+
+ // 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).
+ JSFunction* samples[kSamplerFrameCount];
+ int count = 0;
+ for (JavaScriptFrameIterator it;
+ count < kSamplerFrameCount && !it.done();
+ it.Advance()) {
+ JavaScriptFrame* frame = it.frame();
+ JSFunction* function = JSFunction::cast(frame->function());
+ int function_size = function->shared()->SourceSize();
+ int threshold_size_factor;
+ if (function_size > kSizeLimit) {
+ threshold_size_factor = sampler_threshold_size_factor;
+ } else {
+ threshold_size_factor = 1;
+ }
+
+ int threshold = sampler_threshold * threshold_size_factor;
+ samples[count++] = function;
+ if (function->IsMarkedForLazyRecompilation()) {
+ Code* unoptimized = function->shared()->code();
+ int nesting = unoptimized->allow_osr_at_loop_nesting_level();
+ if (nesting == 0) AttemptOnStackReplacement(function);
+ int new_nesting = Min(nesting + 1, Code::kMaxLoopNestingMarker);
+ unoptimized->set_allow_osr_at_loop_nesting_level(new_nesting);
+ } else if (LookupSample(function) >= threshold) {
+ if (IsOptimizable(function)) {
+ Optimize(function, false, 0);
+ CompilationCache::MarkForEagerOptimizing(Handle<JSFunction>(function));
+ }
+ }
+ }
+
+ // Add the collected functions as samples. It's important not to do
+ // this as part of collecting them because this will interfere with
+ // the sample lookup in case of recursive functions.
+ for (int i = 0; i < count; i++) {
+ AddSample(samples[i], kSamplerFrameWeight[i]);
+ }
+}
+
+
+void RuntimeProfiler::OptimizeSoon(JSFunction* function) {
+ if (!IsOptimizable(function)) return;
+ PendingListNode* node = new PendingListNode(function);
+ node->set_next(optimize_soon_list);
+ optimize_soon_list = node;
+}
+
+
+void RuntimeProfiler::NotifyTick() {
+ StackGuard::RequestRuntimeProfilerTick();
+}
+
+
+void RuntimeProfiler::MarkCompactPrologue(bool is_compacting) {
+ if (is_compacting) {
+ // Clear all samples before mark-sweep-compact because every
+ // function might move.
+ ClearSampleBuffer();
+ } else {
+ // Clear only new space entries on mark-sweep since none of the
+ // old-space functions will move.
+ ClearSampleBufferNewSpaceEntries();
+ }
+}
+
+
+bool IsEqual(void* first, void* second) {
+ return first == second;
+}
+
+
+void RuntimeProfiler::Setup() {
+ ClearSampleBuffer();
+ // If the ticker hasn't already started, make sure to do so to get
+ // the ticks for the runtime profiler.
+ if (IsEnabled()) Logger::EnsureTickerStarted();
+}
+
+
+void RuntimeProfiler::Reset() {
+ sampler_threshold = kSamplerThresholdInit;
+ sampler_threshold_size_factor = kSamplerThresholdSizeFactorInit;
+}
+
+
+void RuntimeProfiler::TearDown() {
+ // Nothing to do.
+}
+
+
+Object** RuntimeProfiler::SamplerWindowAddress() {
+ return sampler_window;
+}
+
+
+int RuntimeProfiler::SamplerWindowSize() {
+ return kSamplerWindowSize;
+}
+
+
+bool RuntimeProfilerRateLimiter::SuspendIfNecessary() {
+ static const int kNonJSTicksThreshold = 100;
+ // We suspend the runtime profiler thread when not running
+ // JavaScript. If the CPU profiler is active we must not do this
+ // because it samples both JavaScript and C++ code.
+ if (RuntimeProfiler::IsEnabled() &&
+ !CpuProfiler::is_profiling() &&
+ !(FLAG_prof && FLAG_prof_auto)) {
+ if (Top::IsInJSState()) {
+ non_js_ticks_ = 0;
+ } else {
+ if (non_js_ticks_ < kNonJSTicksThreshold) {
+ ++non_js_ticks_;
+ } else {
+ if (Top::WaitForJSState()) return true;
+ }
+ }
+ }
+ return false;
+}
+
+
+} } // namespace v8::internal