Enhance ThreadManager to allow a expiration time interval to be assigned
to tasks, and expire those tasks after that time limit has passed.
Enhance TNonblockingServer to utilize this capability so it can be used
for overload resilience.
Note: expired entries are only removed from the queue head, so the
mechanism in ThreadManager may not do what you expect if you have
heterogeneous expiration times. That's not an issue with
TNonblockingServer (which will give all tasks the same limit) and might
not be in other cases where most tasks have the same limit and the rest
execute quickly. A full-up timeout queue would be more complex and have
greater overhead than that used here. It's unnecessary for the task at
hand so I didn't go that route...
The TNonblocking interface is simple: a setTaskExpireTime() accepts a
64-bit millisecond argument. 0 means infinite. A getTaskExpireTime()
accessor completes the interface.
The ThreadManager interface involves an added argument to add() for the
expiration interval and a setExpireCallback() function for setting a
callback that is called for expired tasks (for this project this is
necessary to shut down the associated connection).
git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@920673
13f79535-47bb-0310-9956-
ffa450edef68
#include "ThreadManager.h"
#include "Exception.h"
#include "Monitor.h"
+#include "Util.h"
#include <boost/shared_ptr.hpp>
workerMaxCount_(0),
idleCount_(0),
pendingTaskCountMax_(0),
+ expiredCount_(0),
state_(ThreadManager::UNINITIALIZED),
monitor_(&mutex_),
maxMonitor_(&mutex_) {}
return pendingTaskCountMax_;
}
+ size_t expiredTaskCount() {
+ Synchronized s(monitor_);
+ size_t result = expiredCount_;
+ expiredCount_ = 0;
+ return result;
+ }
+
void pendingTaskCountMax(const size_t value) {
Synchronized s(monitor_);
pendingTaskCountMax_ = value;
bool canSleep();
- void add(shared_ptr<Runnable> value, int64_t timeout);
+ void add(shared_ptr<Runnable> value, int64_t timeout, int64_t expiration);
void remove(shared_ptr<Runnable> task);
shared_ptr<Runnable> removeNextPending();
+ void removeExpiredTasks();
+
+ void setExpireCallback(ExpireCallback expireCallback);
+
private:
void stopImpl(bool join);
size_t workerMaxCount_;
size_t idleCount_;
size_t pendingTaskCountMax_;
+ size_t expiredCount_;
+ ExpireCallback expireCallback_;
ThreadManager::STATE state_;
shared_ptr<ThreadFactory> threadFactory_;
COMPLETE
};
- Task(shared_ptr<Runnable> runnable) :
+ Task(shared_ptr<Runnable> runnable, int64_t expiration=0LL) :
runnable_(runnable),
- state_(WAITING) {}
+ state_(WAITING),
+ expireTime_(expiration != 0LL ? Util::currentTime() + expiration : 0LL) {}
~Task() {}
return runnable_;
}
+ int64_t getExpireTime() const {
+ return expireTime_;
+ }
+
private:
shared_ptr<Runnable> runnable_;
friend class ThreadManager::Worker;
STATE state_;
+ int64_t expireTime_;
};
class ThreadManager::Worker: public Runnable {
}
if (active) {
+ manager_->removeExpiredTasks();
+
if (!manager_->tasks_.empty()) {
task = manager_->tasks_.front();
manager_->tasks_.pop();
return idMap_.find(id) == idMap_.end();
}
- void ThreadManager::Impl::add(shared_ptr<Runnable> value, int64_t timeout) {
+ void ThreadManager::Impl::add(shared_ptr<Runnable> value,
+ int64_t timeout,
+ int64_t expiration) {
Guard g(mutex_);
if (state_ != ThreadManager::STARTED) {
throw IllegalStateException();
}
+ removeExpiredTasks();
if (pendingTaskCountMax_ > 0 && (tasks_.size() >= pendingTaskCountMax_)) {
if (canSleep() && timeout >= 0) {
while (pendingTaskCountMax_ > 0 && tasks_.size() >= pendingTaskCountMax_) {
}
}
- tasks_.push(shared_ptr<ThreadManager::Task>(new ThreadManager::Task(value)));
+ tasks_.push(shared_ptr<ThreadManager::Task>(new ThreadManager::Task(value, expiration)));
// If idle thread is available notify it, otherwise all worker threads are
// running and will get around to this task in time.
return task->getRunnable();
}
+void ThreadManager::Impl::removeExpiredTasks() {
+ int64_t now = 0LL; // we won't ask for the time untile we need it
+
+ // note that this loop breaks at the first non-expiring task
+ while (!tasks_.empty()) {
+ shared_ptr<ThreadManager::Task> task = tasks_.front();
+ if (task->getExpireTime() == 0LL) {
+ break;
+ }
+ if (now == 0LL) {
+ now = Util::currentTime();
+ }
+ if (task->getExpireTime() > now) {
+ break;
+ }
+ if (expireCallback_) {
+ expireCallback_(task->getRunnable());
+ }
+ tasks_.pop();
+ expiredCount_++;
+ }
+}
+
+
+void ThreadManager::Impl::setExpireCallback(ExpireCallback expireCallback) {
+ expireCallback_ = expireCallback;
+}
+
class SimpleThreadManager : public ThreadManager::Impl {
public:
#define _THRIFT_CONCURRENCY_THREADMANAGER_H_ 1
#include <boost/shared_ptr.hpp>
+#include <tr1/functional>
#include <sys/types.h>
#include "Thread.h"
ThreadManager() {}
public:
+ class Task;
+ typedef std::tr1::function<void(boost::shared_ptr<Runnable>)> ExpireCallback;
+
virtual ~ThreadManager() {}
/**
*/
virtual size_t pendingTaskCountMax() const = 0;
+ /**
+ * Gets the number of tasks which have been expired without being run.
+ */
+ virtual size_t expiredTaskCount() = 0;
+
/**
* Adds a task to be executed at some time in the future by a worker thread.
*
* is specified. Specific cases:
* timeout = 0 : Wait forever to queue task.
* timeout = -1 : Return immediately if pending task count exceeds specified max
+ * @param expiration when nonzero, the number of milliseconds the task is valid
+ * to be run; if exceeded, the task will be dropped off the queue and not run.
*
* @throws TooManyPendingTasksException Pending task count exceeds max pending task count
*/
- virtual void add(boost::shared_ptr<Runnable>task, int64_t timeout=0LL) = 0;
+ virtual void add(boost::shared_ptr<Runnable>task,
+ int64_t timeout=0LL,
+ int64_t expiration=0LL) = 0;
/**
* Removes a pending task
*/
virtual boost::shared_ptr<Runnable> removeNextPending() = 0;
+ /**
+ * Remove tasks from front of task queue that have expired.
+ */
+ virtual void removeExpiredTasks() = 0;
+
+ /**
+ * Set a callback to be called when a task is expired and not run.
+ *
+ * @param expireCallback a function called with the shared_ptr<Runnable> for
+ * the expired task.
+ */
+ virtual void setExpireCallback(ExpireCallback expireCallback) = 0;
+
static boost::shared_ptr<ThreadManager> newThreadManager();
/**
}
}
+void TNonblockingServer::setThreadManager(boost::shared_ptr<ThreadManager> threadManager) {
+ threadManager_ = threadManager;
+ if (threadManager != NULL) {
+ threadManager->setExpireCallback(std::tr1::bind(&TNonblockingServer::expireClose, this, std::tr1::placeholders::_1));
+ threadPoolProcessing_ = true;
+ } else {
+ threadPoolProcessing_ = false;
+ }
+}
+
bool TNonblockingServer::serverOverloaded() {
size_t activeConnections = numTConnections_ - connectionStack_.size();
if (numActiveProcessors_ > maxActiveProcessors_ ||
return false;
}
+void TNonblockingServer::expireClose(boost::shared_ptr<Runnable> task) {
+ TConnection* connection =
+ static_cast<TConnection::Task*>(task.get())->getTConnection();
+ assert(connection && connection->getServer()
+ && connection->getState() == APP_WAIT_TASK);
+ connection->forceClose();
+}
+
/**
* Main workhorse function, starts up the server listening on a port and
* loops over the libevent handler.
/// Limit for number of open connections
size_t maxConnections_;
+ /// Time in milliseconds before an unperformed task expires (0 == infinite).
+ int64_t taskExpireTime_;
+
/**
* Hysteresis for overload state. This is the fraction of the overload
* value that needs to be reached before the overload state is cleared;
connectionStackLimit_(CONNECTION_STACK_LIMIT),
maxActiveProcessors_(MAX_ACTIVE_PROCESSORS),
maxConnections_(MAX_CONNECTIONS),
+ taskExpireTime_(0),
overloadHysteresis_(0.8),
overloadAction_(T_OVERLOAD_NO_ACTION),
idleBufferMemLimit_(IDLE_BUFFER_MEM_LIMIT),
connectionStackLimit_(CONNECTION_STACK_LIMIT),
maxActiveProcessors_(MAX_ACTIVE_PROCESSORS),
maxConnections_(MAX_CONNECTIONS),
+ taskExpireTime_(0),
overloadHysteresis_(0.8),
overloadAction_(T_OVERLOAD_NO_ACTION),
idleBufferMemLimit_(IDLE_BUFFER_MEM_LIMIT),
connectionStackLimit_(CONNECTION_STACK_LIMIT),
maxActiveProcessors_(MAX_ACTIVE_PROCESSORS),
maxConnections_(MAX_CONNECTIONS),
+ taskExpireTime_(0),
overloadHysteresis_(0.8),
overloadAction_(T_OVERLOAD_NO_ACTION),
idleBufferMemLimit_(IDLE_BUFFER_MEM_LIMIT),
overloaded_(false),
nConnectionsDropped_(0),
- nTotalConnectionsDropped_(0) {
+ nTotalConnectionsDropped_(0) {
setInputTransportFactory(inputTransportFactory);
setOutputTransportFactory(outputTransportFactory);
setInputProtocolFactory(inputProtocolFactory);
~TNonblockingServer() {}
- void setThreadManager(boost::shared_ptr<ThreadManager> threadManager) {
- threadManager_ = threadManager;
- threadPoolProcessing_ = (threadManager != NULL);
- }
+ void setThreadManager(boost::shared_ptr<ThreadManager> threadManager);
boost::shared_ptr<ThreadManager> getThreadManager() {
return threadManager_;
}
void addTask(boost::shared_ptr<Runnable> task) {
- threadManager_->add(task);
+ threadManager_->add(task, 0LL, taskExpireTime_);
}
event_base* getEventBase() const {
overloadAction_ = overloadAction;
}
+ /**
+ * Get the time in milliseconds after which a task expires (0 == infinite).
+ *
+ * @return a 64-bit time in milliseconds.
+ */
+ int64_t getTaskExpireTime() const {
+ return taskExpireTime_;
+ }
+
+ /**
+ * Set the time in milliseconds after which a task expires (0 == infinite).
+ *
+ * @param taskExpireTime a 64-bit time in milliseconds.
+ */
+ void setTaskExpireTime(int64_t taskExpireTime) {
+ taskExpireTime_ = taskExpireTime;
+ }
+
/**
* Determine if the server is currently overloaded.
* This function checks the maximums for open connections and connections
*/
void returnConnection(TConnection* connection);
+ /**
+ * Callback function that the threadmanager calls when a task reaches
+ * its expiration time. It is needed to clean up the expired connection.
+ *
+ * @param task the runnable associated with the expired task.
+ */
+ void expireClose(boost::shared_ptr<Runnable> task);
+
/**
* C-callable event handler for listener events. Provides a callback
* that libevent can understand which invokes server->handleEvent().
Code Review / common / thrift.git / commitdiff
