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src: drop homegrown thread pool, use libplatform

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Drop the homegrown thread pool that was introduced in commit 50839a0
("v8_platform: provide default v8::Platform impl") and use one from
V8's libplatform library.  Performance is comparable and it removes
a few hundred lines of code.

The calls to v8::platform::PumpMessageLoop() are currently no-ops
because V8 does not (yet?) use v8::Platform::CallOnForegroundThread().

Packagers that link against a shared libv8 now also need to make
libv8_platform available.

PR-URL: https://github.com/iojs/io.js/pull/1329
Reviewed-By: Fedor Indutny <fedor@indutny.com>
This commit is contained in:
Ben Noordhuis 2015-04-02 23:51:01 +02:00
parent 87053e8aee
commit 4a801c211c
5 changed files with 18 additions and 257 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
configure vendored
View File

@ -664,7 +664,7 @@ def configure_v8(o):
if options.shared_v8_libname:
o['libraries'] += ['-l%s' % options.shared_v8_libname]
elif options.shared_v8:
o['libraries'] += ['-lv8']
o['libraries'] += ['-lv8', '-lv8_platform']
if options.shared_v8_includes:
o['include_dirs'] += [options.shared_v8_includes]

8
node.gyp
View File

@ -108,7 +108,6 @@
'src/node_main.cc',
'src/node_os.cc',
'src/node_v8.cc',
'src/node_v8_platform.cc',
'src/node_stat_watcher.cc',
'src/node_watchdog.cc',
'src/node_zlib.cc',
@ -312,7 +311,12 @@
'deps/v8/include/v8.h',
'deps/v8/include/v8-debug.h',
],
'dependencies': [ 'deps/v8/tools/gyp/v8.gyp:v8' ],
'dependencies': [
'deps/v8/tools/gyp/v8.gyp:v8',
'deps/v8/tools/gyp/v8.gyp:v8_libplatform',
],
# libplatform/libplatform.h includes include/v8platform.h
'include_dirs': [ 'deps/v8' ],
}],
[ 'node_shared_zlib=="false"', {

13
src/node.cc
View File

@ -5,7 +5,6 @@
#include "node_http_parser.h"
#include "node_javascript.h"
#include "node_version.h"
#include "node_v8_platform.h"
#if defined HAVE_PERFCTR
#include "node_counters.h"
@ -38,6 +37,7 @@
#include "string_bytes.h"
#include "util.h"
#include "uv.h"
#include "libplatform/libplatform.h"
#include "v8-debug.h"
#include "v8-profiler.h"
#include "zlib.h"
@ -140,6 +140,7 @@ static bool debugger_running;
static uv_async_t dispatch_debug_messages_async;
static Isolate* node_isolate = nullptr;
static v8::Platform* default_platform;
class ArrayBufferAllocator : public ArrayBuffer::Allocator {
public:
@ -3824,8 +3825,11 @@ static void StartNodeInstance(void* arg) {
bool more;
do {
v8::platform::PumpMessageLoop(default_platform, isolate);
more = uv_run(env->event_loop(), UV_RUN_ONCE);
if (more == false) {
v8::platform::PumpMessageLoop(default_platform, isolate);
EmitBeforeExit(env);
// Emit `beforeExit` if the loop became alive either after emitting
@ -3872,7 +3876,9 @@ int Start(int argc, char** argv) {
V8::SetEntropySource(crypto::EntropySource);
#endif
V8::InitializePlatform(new Platform(4));
const int thread_pool_size = 4;
default_platform = v8::platform::CreateDefaultPlatform(thread_pool_size);
V8::InitializePlatform(default_platform);
V8::Initialize();
int exit_code = 1;
@ -3889,6 +3895,9 @@ int Start(int argc, char** argv) {
}
V8::Dispose();
delete default_platform;
default_platform = nullptr;
delete[] exec_argv;
exec_argv = nullptr;

178
src/node_v8_platform.cc
View File

@ -1,178 +0,0 @@
// Copyright Fedor Indutny and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
#include "node_v8_platform.h"
#include "node.h"
#include "util.h"
#include "util-inl.h"
#include "uv.h"
#include "v8-platform.h"
namespace node {
using v8::Task;
using v8::Isolate;
// The last task to encounter before killing the worker
class StopTask : public Task {
public:
void Run() {}
};
static StopTask stop_task_;
Platform::Platform(unsigned int worker_count) : worker_count_(worker_count) {
workers_ = new uv_thread_t[worker_count_];
for (unsigned int i = 0; i < worker_count_; i++) {
int err;
err = uv_thread_create(worker_at(i), WorkerBody, this);
CHECK_EQ(err, 0);
}
}
Platform::~Platform() {
// Push stop task
for (unsigned int i = 0; i < worker_count(); i++)
global_queue()->Push(&stop_task_);
// And wait for workers to exit
for (unsigned int i = 0; i < worker_count(); i++) {
int err;
err = uv_thread_join(worker_at(i));
CHECK_EQ(err, 0);
}
delete[] workers_;
}
void Platform::CallOnBackgroundThread(Task* task,
ExpectedRuntime expected_runtime) {
global_queue()->Push(task);
}
void Platform::CallOnForegroundThread(Isolate* isolate, Task* task) {
// TODO(indutny): create per-isolate thread pool
global_queue()->Push(task);
}
double Platform::MonotonicallyIncreasingTime() {
// uv_hrtime() returns a uint64_t but doubles can only represent integrals up
// to 2^53 accurately. Take steps to prevent loss of precision on overflow.
const uint64_t timestamp = uv_hrtime();
const uint64_t billion = 1000 * 1000 * 1000;
const uint64_t seconds = timestamp / billion;
const uint64_t nanoseconds = timestamp % billion;
return seconds + 1.0 / nanoseconds;
}
void Platform::WorkerBody(void* arg) {
Platform* p = static_cast<Platform*>(arg);
for (;;) {
Task* task = p->global_queue()->Shift();
if (task == &stop_task_)
break;
task->Run();
delete task;
}
}
TaskQueue::TaskQueue() : read_off_(0), write_off_(0) {
CHECK_EQ(0, uv_cond_init(&read_cond_));
CHECK_EQ(0, uv_cond_init(&write_cond_));
CHECK_EQ(0, uv_mutex_init(&mutex_));
}
TaskQueue::~TaskQueue() {
uv_mutex_lock(&mutex_);
CHECK_EQ(read_off_, write_off_);
uv_mutex_unlock(&mutex_);
uv_cond_destroy(&read_cond_);
uv_cond_destroy(&write_cond_);
uv_mutex_destroy(&mutex_);
}
void TaskQueue::Push(Task* task) {
uv_mutex_lock(&mutex_);
while (can_write() == false)
uv_cond_wait(&write_cond_, &mutex_); // Wait until there is a free slot.
ring_[write_off_] = task;
write_off_ = next(write_off_);
uv_cond_signal(&read_cond_);
uv_mutex_unlock(&mutex_);
}
Task* TaskQueue::Shift() {
uv_mutex_lock(&mutex_);
while (can_read() == false)
uv_cond_wait(&read_cond_, &mutex_);
Task* task = ring_[read_off_];
if (can_write() == false)
uv_cond_signal(&write_cond_); // Signal waiters that we freed up a slot.
read_off_ = next(read_off_);
uv_mutex_unlock(&mutex_);
return task;
}
unsigned int TaskQueue::next(unsigned int n) {
return (n + 1) % ARRAY_SIZE(TaskQueue {}.ring_);
}
bool TaskQueue::can_read() const {
return read_off_ != write_off_;
}
// The read pointer chases the write pointer in the circular queue.
// This method checks that the write pointer hasn't advanced so much
// that it has gone full circle and caught up with the read pointer.
//
// can_write() returns false when there is an empty slot but the read pointer
// points to the first element and the write pointer to the last element.
// That should be rare enough that it is not worth the extra bookkeeping
// to work around that. It's not harmful either, just mildly inefficient.
bool TaskQueue::can_write() const {
return next(write_off_) != read_off_;
}
} // namespace node

74
src/node_v8_platform.h
View File

@ -1,74 +0,0 @@
// Copyright Fedor Indutny and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
#ifndef SRC_NODE_V8_PLATFORM_H_
#define SRC_NODE_V8_PLATFORM_H_
#include "uv.h"
#include "v8-platform.h"
namespace node {
class TaskQueue {
public:
TaskQueue();
~TaskQueue();
void Push(v8::Task* task);
v8::Task* Shift();
private:
static unsigned int next(unsigned int n);
bool can_read() const;
bool can_write() const;
uv_cond_t read_cond_;
uv_cond_t write_cond_;
uv_mutex_t mutex_;
unsigned int read_off_;
unsigned int write_off_;
v8::Task* ring_[1024];
};
class Platform : public v8::Platform {
public:
explicit Platform(unsigned int worker_count);
virtual ~Platform() override;
void CallOnBackgroundThread(v8::Task* task,
ExpectedRuntime expected_runtime) override;
void CallOnForegroundThread(v8::Isolate* isolate, v8::Task* task) override;
double MonotonicallyIncreasingTime() override;
protected:
static void WorkerBody(void* arg);
inline TaskQueue* global_queue() { return &global_queue_; }
inline uv_thread_t* worker_at(unsigned int index) { return &workers_[index]; }
inline unsigned int worker_count() const { return worker_count_; }
uv_thread_t* workers_;
unsigned int worker_count_;
TaskQueue global_queue_;
};
} // namespace node
#endif // SRC_NODE_V8_PLATFORM_H_