AuroraMiddleware/v8
1
0
Fork 0
Code Issues 2 Pull Requests Releases Wiki Activity

[wasm] Reduce number of background compile scopes

Browse Source 
This reduces the number of {BackgroundCompileScope}s per compilation
unit from 2 to 1. This reduces the number of concurrent accesses to the
{SharedMutex}.

R=ahaas@chromium.org

Bug: v8:8916
Cq-Include-Trybots: luci.v8.try:v8_linux64_tsan_rel
Change-Id: I872683101dfc9361aa7054ea67f16e3f3f2b82b1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1495989
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60034}
This commit is contained in:
Clemens Hammacher 2019-03-05 15:00:02 +01:00 committed by Commit Bot
parent 2222a9d67e
commit e4bff229b2
1 changed files with 53 additions and 44 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

97
src/wasm/module-compiler.cc
View File

@ -646,25 +646,64 @@ class BackgroundCompileTask : public CancelableTask {
TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.wasm"),
"BackgroundCompileTask::RunInternal");
// These fields are initialized before getting the first unit of work.
double deadline = MonotonicallyIncreasingTimeInMs() + 50.0;
// These fields are initialized in a {BackgroundCompileScope} before
// starting compilation.
base::Optional<CompilationEnv> env;
std::shared_ptr<WireBytesStorage> wire_bytes;
std::shared_ptr<const WasmModule> module;
std::unique_ptr<WasmCompilationUnit> unit;
WasmFeatures detected_features = kNoWasmFeatures;
double deadline = MonotonicallyIncreasingTimeInMs() + 50.0;
// Preparation (synchronized): Initialize the fields above and get the first
// compilation unit.
{
BackgroundCompileScope compile_scope(token_);
if (compile_scope.cancelled()) return;
env.emplace(compile_scope.native_module()->CreateCompilationEnv());
wire_bytes = compile_scope.compilation_state()->GetWireBytesStorage();
module = compile_scope.native_module()->shared_module();
unit = compile_scope.compilation_state()->GetNextCompilationUnit();
if (unit == nullptr) {
compile_scope.compilation_state()->OnBackgroundTaskStopped(
detected_features);
return;
}
}
bool compilation_failed = false;
while (true) {
// Step 1 (synchronized): Get a WasmCompilationUnit, and initialize some
// fields if this is the first unit executed by this task.
std::unique_ptr<WasmCompilationUnit> unit;
// (asynchronous): Execute the compilation.
WasmCompilationResult result = unit->ExecuteCompilation(
&env.value(), wire_bytes, async_counters_.get(), &detected_features);
// (synchronized): Publish the compilation result and get the next unit.
{
BackgroundCompileScope compile_scope(token_);
if (compile_scope.cancelled()) return;
if (!env.has_value()) {
env.emplace(compile_scope.native_module()->CreateCompilationEnv());
wire_bytes = compile_scope.compilation_state()->GetWireBytesStorage();
module = compile_scope.native_module()->shared_module();
WasmCode* code =
unit->Publish(std::move(result), compile_scope.native_module());
if (code == nullptr) {
// Compile error.
compile_scope.compilation_state()->OnBackgroundTaskStopped(
detected_features);
compilation_failed = true;
break;
}
// Successfully finished one unit.
compile_scope.compilation_state()->OnFinishedUnit(
unit->requested_tier(), code);
if (deadline < MonotonicallyIncreasingTimeInMs()) {
compile_scope.compilation_state()->ReportDetectedFeatures(
detected_features);
compile_scope.compilation_state()->RestartBackgroundCompileTask();
return;
}
// Get next unit.
unit = compile_scope.compilation_state()->GetNextCompilationUnit();
if (unit == nullptr) {
compile_scope.compilation_state()->OnBackgroundTaskStopped(
@ -672,41 +711,11 @@ class BackgroundCompileTask : public CancelableTask {
return;
}
}
// Step 2: Execute the compilation.
WasmCompilationResult result = unit->ExecuteCompilation(
&env.value(), wire_bytes, async_counters_.get(), &detected_features);
// Step 3 (synchronized): Publish the compilation result.
bool cancel_compilation = false;
{
BackgroundCompileScope compile_scope(token_);
if (compile_scope.cancelled()) return;
WasmCode* code =
unit->Publish(std::move(result), compile_scope.native_module());
if (code == nullptr) {
compile_scope.compilation_state()->OnBackgroundTaskStopped(
detected_features);
// Also, cancel all remaining compilation.
cancel_compilation = true;
} else {
compile_scope.compilation_state()->OnFinishedUnit(
unit->requested_tier(), code);
if (deadline < MonotonicallyIncreasingTimeInMs()) {
compile_scope.compilation_state()->ReportDetectedFeatures(
detected_features);
compile_scope.compilation_state()->RestartBackgroundCompileTask();
return;
}
}
}
if (cancel_compilation) {
token_->Cancel();
return;
}
}
UNREACHABLE(); // Loop exits via explicit return.
// We only get here if compilation failed. Other exits return directly.
DCHECK(compilation_failed);
USE(compilation_failed);
token_->Cancel();
}
private: