icinga2/lib/base/threadpool.cpp

373 lines
9.3 KiB
C++

/******************************************************************************
* Icinga 2 *
* Copyright (C) 2012 Icinga Development Team (http://www.icinga.org/) *
* *
* This program is free software; you can redistribute it and/or *
* modify it under the terms of the GNU General Public License *
* as published by the Free Software Foundation; either version 2 *
* of the License, or (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program; if not, write to the Free Software Foundation *
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. *
******************************************************************************/
#include "base/threadpool.h"
#include "base/logger_fwd.h"
#include "base/convert.h"
#include "base/utility.h"
#include <sstream>
#include <iostream>
#include <boost/bind.hpp>
#include <boost/exception/diagnostic_information.hpp>
#include <boost/foreach.hpp>
using namespace icinga;
ThreadPool::ThreadPool(void)
: m_Stopped(false), m_ThreadDeaths(0), m_WaitTime(0),
m_ServiceTime(0), m_TaskCount(0)
{
for (int i = 0; i < 2; i++)
SpawnWorker();
m_ManagerThread = boost::thread(boost::bind(&ThreadPool::ManagerThreadProc, this));
m_StatsThread = boost::thread(boost::bind(&ThreadPool::StatsThreadProc, this));
}
ThreadPool::~ThreadPool(void)
{
Stop();
Join();
}
void ThreadPool::Stop(void)
{
boost::mutex::scoped_lock lock(m_Mutex);
m_Stopped = true;
m_WorkCV.notify_all();
m_MgmtCV.notify_all();
}
/**
* Waits for all worker threads to finish.
*/
void ThreadPool::Join(void)
{
boost::mutex::scoped_lock lock(m_Mutex);
while (!m_Stopped || !m_WorkItems.empty()) {
lock.unlock();
Utility::Sleep(0.5);
lock.lock();
}
int alive;
do {
alive = 0;
for (int i = 0; i < sizeof(m_ThreadStats) / sizeof(m_ThreadStats[0]); i++) {
if (m_ThreadStats[i].State != ThreadDead) {
alive++;
KillWorker();
}
}
if (alive > 0) {
lock.unlock();
Utility::Sleep(0.5);
lock.lock();
}
} while (alive > 0);
m_ManagerThread.join();
m_StatsThread.join();
}
/**
* Waits for work items and processes them.
*/
void ThreadPool::QueueThreadProc(int tid)
{
std::ostringstream idbuf;
idbuf << "TP " << this << " Worker #" << tid;
Utility::SetThreadName(idbuf.str());
for (;;) {
WorkItem wi;
{
boost::mutex::scoped_lock lock(m_Mutex);
UpdateThreadUtilization(tid, ThreadIdle);
while (m_WorkItems.empty() && !m_Stopped && m_ThreadDeaths == 0)
m_WorkCV.wait(lock);
if (m_ThreadDeaths > 0) {
m_ThreadDeaths--;
break;
}
if (m_WorkItems.empty() && m_Stopped)
break;
wi = m_WorkItems.front();
m_WorkItems.pop_front();
UpdateThreadUtilization(tid, ThreadBusy);
}
double st = Utility::GetTime();;
#ifdef _DEBUG
# ifdef RUSAGE_THREAD
struct rusage usage_start, usage_end;
(void) getrusage(RUSAGE_THREAD, &usage_start);
# endif /* RUSAGE_THREAD */
#endif /* _DEBUG */
try {
wi.Callback();
} catch (const std::exception& ex) {
std::ostringstream msgbuf;
msgbuf << "Exception thrown in event handler: " << std::endl
<< boost::diagnostic_information(ex);
Log(LogCritical, "base", msgbuf.str());
} catch (...) {
Log(LogCritical, "base", "Exception of unknown type thrown in event handler.");
}
double et = Utility::GetTime();
double latency = st - wi.Timestamp;
{
boost::mutex::scoped_lock lock(m_Mutex);
m_WaitTime += latency;
m_ServiceTime += et - st;
m_TaskCount++;
if (latency > m_MaxLatency)
m_MaxLatency = latency;
}
#ifdef _DEBUG
# ifdef RUSAGE_THREAD
(void) getrusage(RUSAGE_THREAD, &usage_end);
double duser = (usage_end.ru_utime.tv_sec - usage_start.ru_utime.tv_sec) +
(usage_end.ru_utime.tv_usec - usage_start.ru_utime.tv_usec) / 1000000.0;
double dsys = (usage_end.ru_stime.tv_sec - usage_start.ru_stime.tv_sec) +
(usage_end.ru_stime.tv_usec - usage_start.ru_stime.tv_usec) / 1000000.0;
double dwait = (et - st) - (duser + dsys);
int dminfaults = usage_end.ru_minflt - usage_start.ru_minflt;
int dmajfaults = usage_end.ru_majflt - usage_start.ru_majflt;
int dvctx = usage_end.ru_nvcsw - usage_start.ru_nvcsw;
int divctx = usage_end.ru_nivcsw - usage_start.ru_nivcsw;
# endif /* RUSAGE_THREAD */
if (et - st > 0.5) {
std::ostringstream msgbuf;
# ifdef RUSAGE_THREAD
msgbuf << "Event call took user:" << duser << "s, system:" << dsys << "s, wait:" << dwait << "s, minor_faults:" << dminfaults << ", major_faults:" << dmajfaults << ", voluntary_csw:" << dvctx << ", involuntary_csw:" << divctx;
# else
msgbuf << "Event call took " << (et - st) << "s";
# endif /* RUSAGE_THREAD */
Log(LogWarning, "base", msgbuf.str());
}
#endif /* _DEBUG */
}
UpdateThreadUtilization(tid, ThreadDead);
}
/**
* Appends a work item to the work queue. Work items will be processed in FIFO order.
*
* @param callback The callback function for the work item.
* @returns true if the item was queued, false otherwise.
*/
bool ThreadPool::Post(const ThreadPool::WorkFunction& callback)
{
boost::mutex::scoped_lock lock(m_Mutex);
if (m_Stopped)
return false;
WorkItem wi;
wi.Callback = callback;
wi.Timestamp = Utility::GetTime();
m_WorkItems.push_back(wi);
m_WorkCV.notify_one();
return true;
}
void ThreadPool::ManagerThreadProc(void)
{
std::ostringstream idbuf;
idbuf << "TP " << this << " Manager";
Utility::SetThreadName(idbuf.str());
for (;;) {
int pending, alive;
double avg_latency, max_latency;
double utilization = 0;
{
boost::mutex::scoped_lock lock(m_Mutex);
m_MgmtCV.timed_wait(lock, boost::posix_time::seconds(5));
if (m_Stopped)
break;
pending = m_WorkItems.size();
alive = 0;
for (int i = 0; i < sizeof(m_ThreadStats) / sizeof(m_ThreadStats[0]); i++) {
if (m_ThreadStats[i].State != ThreadDead) {
alive++;
utilization += m_ThreadStats[i].Utilization * 100;
}
}
utilization /= alive;
if (m_TaskCount > 0)
avg_latency = m_WaitTime / (m_TaskCount * 1.0);
else
avg_latency = 0;
if (utilization < 60 || utilization > 80 || alive < 2) {
int tthreads = ceil((utilization * alive) / 80.0) - alive;
/* Don't ever kill the last 2 threads. */
if (alive + tthreads < 2)
tthreads = 2 - alive;
/* Spawn more workers if there are outstanding work items. */
if (tthreads > 0 && pending > 0)
tthreads = 8;
for (int i = 0; i < -tthreads; i++)
KillWorker();
for (int i = 0; i < tthreads; i++)
SpawnWorker();
}
m_WaitTime = 0;
m_ServiceTime = 0;
m_TaskCount = 0;
max_latency = m_MaxLatency;
m_MaxLatency = 0;
}
std::ostringstream msgbuf;
msgbuf << "Pending tasks: " << pending << "; Average latency: "
<< (long)(avg_latency * 1000) << "ms"
<< "; Max latency: " << (long)(max_latency * 1000) << "ms"
<< "; Threads: " << alive
<< "; Pool utilization: " << utilization << "%";
Log(LogInformation, "base", msgbuf.str());
}
}
/**
* Note: Caller must hold m_Mutex
*/
void ThreadPool::SpawnWorker(void)
{
for (int i = 0; i < sizeof(m_ThreadStats) / sizeof(m_ThreadStats[0]); i++) {
if (m_ThreadStats[i].State == ThreadDead) {
Log(LogDebug, "debug", "Spawning worker thread.");
m_ThreadStats[i] = ThreadStats(ThreadIdle);
boost::thread worker(boost::bind(&ThreadPool::QueueThreadProc, this, i));
worker.detach();
break;
}
}
}
/**
* Note: Caller must hold m_Mutex.
*/
void ThreadPool::KillWorker(void)
{
Log(LogDebug, "base", "Killing worker thread.");
m_ThreadDeaths++;
}
void ThreadPool::StatsThreadProc(void)
{
std::ostringstream idbuf;
idbuf << "TP " << this << " Stats";
Utility::SetThreadName(idbuf.str());
for (;;) {
boost::mutex::scoped_lock lock(m_Mutex);
m_MgmtCV.timed_wait(lock, boost::posix_time::milliseconds(250));
if (m_Stopped)
break;
for (int i = 0; i < sizeof(m_ThreadStats) / sizeof(m_ThreadStats[0]); i++)
UpdateThreadUtilization(i);
}
}
/**
* Note: Caller must hold m_Mutex.
*/
void ThreadPool::UpdateThreadUtilization(int tid, ThreadState state)
{
double utilization;
switch (m_ThreadStats[tid].State) {
case ThreadDead:
return;
case ThreadIdle:
utilization = 0;
break;
case ThreadBusy:
utilization = 1;
break;
default:
ASSERT(0);
}
double now = Utility::GetTime();
double time = now - m_ThreadStats[tid].LastUpdate;
const double avg_time = 5.0;
if (time > avg_time)
time = avg_time;
m_ThreadStats[tid].Utilization = (m_ThreadStats[tid].Utilization * (avg_time - time) + utilization * time) / avg_time;
m_ThreadStats[tid].LastUpdate = now;
if (state != ThreadUnspecified)
m_ThreadStats[tid].State = state;
}