drain.hh revision 10912
19342SAndreas.Sandberg@arm.com/* 210910Sandreas.sandberg@arm.com * Copyright (c) 2012, 2015 ARM Limited 39342SAndreas.Sandberg@arm.com * All rights reserved 49342SAndreas.Sandberg@arm.com * 59342SAndreas.Sandberg@arm.com * The license below extends only to copyright in the software and shall 69342SAndreas.Sandberg@arm.com * not be construed as granting a license to any other intellectual 79342SAndreas.Sandberg@arm.com * property including but not limited to intellectual property relating 89342SAndreas.Sandberg@arm.com * to a hardware implementation of the functionality of the software 99342SAndreas.Sandberg@arm.com * licensed hereunder. You may use the software subject to the license 109342SAndreas.Sandberg@arm.com * terms below provided that you ensure that this notice is replicated 119342SAndreas.Sandberg@arm.com * unmodified and in its entirety in all distributions of the software, 129342SAndreas.Sandberg@arm.com * modified or unmodified, in source code or in binary form. 139342SAndreas.Sandberg@arm.com * 149342SAndreas.Sandberg@arm.com * Redistribution and use in source and binary forms, with or without 159342SAndreas.Sandberg@arm.com * modification, are permitted provided that the following conditions are 169342SAndreas.Sandberg@arm.com * met: redistributions of source code must retain the above copyright 179342SAndreas.Sandberg@arm.com * notice, this list of conditions and the following disclaimer; 189342SAndreas.Sandberg@arm.com * redistributions in binary form must reproduce the above copyright 199342SAndreas.Sandberg@arm.com * notice, this list of conditions and the following disclaimer in the 209342SAndreas.Sandberg@arm.com * documentation and/or other materials provided with the distribution; 219342SAndreas.Sandberg@arm.com * neither the name of the copyright holders nor the names of its 229342SAndreas.Sandberg@arm.com * contributors may be used to endorse or promote products derived from 239342SAndreas.Sandberg@arm.com * this software without specific prior written permission. 249342SAndreas.Sandberg@arm.com * 259342SAndreas.Sandberg@arm.com * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 269342SAndreas.Sandberg@arm.com * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 279342SAndreas.Sandberg@arm.com * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 289342SAndreas.Sandberg@arm.com * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 299342SAndreas.Sandberg@arm.com * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 309342SAndreas.Sandberg@arm.com * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 319342SAndreas.Sandberg@arm.com * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 329342SAndreas.Sandberg@arm.com * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 339342SAndreas.Sandberg@arm.com * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 349342SAndreas.Sandberg@arm.com * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 359342SAndreas.Sandberg@arm.com * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 369342SAndreas.Sandberg@arm.com * 379342SAndreas.Sandberg@arm.com * Authors: Andreas Sandberg 389342SAndreas.Sandberg@arm.com */ 399342SAndreas.Sandberg@arm.com 409342SAndreas.Sandberg@arm.com#ifndef __SIM_DRAIN_HH__ 419342SAndreas.Sandberg@arm.com#define __SIM_DRAIN_HH__ 429342SAndreas.Sandberg@arm.com 4310912Sandreas.sandberg@arm.com#include <atomic> 4410912Sandreas.sandberg@arm.com#include <mutex> 4510912Sandreas.sandberg@arm.com#include <unordered_set> 469342SAndreas.Sandberg@arm.com 479342SAndreas.Sandberg@arm.com#include "base/flags.hh" 489342SAndreas.Sandberg@arm.com 4910910Sandreas.sandberg@arm.comclass Drainable; 5010910Sandreas.sandberg@arm.com 5110910Sandreas.sandberg@arm.com#ifndef SWIG // SWIG doesn't support strongly typed enums 5210910Sandreas.sandberg@arm.com/** 5310910Sandreas.sandberg@arm.com * Object drain/handover states 5410910Sandreas.sandberg@arm.com * 5510910Sandreas.sandberg@arm.com * An object starts out in the Running state. When the simulator 5610910Sandreas.sandberg@arm.com * prepares to take a snapshot or prepares a CPU for handover, it 5710910Sandreas.sandberg@arm.com * calls the drain() method to transfer the object into the Draining 5810910Sandreas.sandberg@arm.com * or Drained state. If any object enters the Draining state 5910910Sandreas.sandberg@arm.com * (Drainable::drain() returning >0), simulation continues until it 6010910Sandreas.sandberg@arm.com * all objects have entered the Drained state. 6110910Sandreas.sandberg@arm.com * 6210910Sandreas.sandberg@arm.com * Before resuming simulation, the simulator calls resume() to 6310910Sandreas.sandberg@arm.com * transfer the object to the Running state. 6410910Sandreas.sandberg@arm.com * 6510910Sandreas.sandberg@arm.com * \note Even though the state of an object (visible to the rest of 6610910Sandreas.sandberg@arm.com * the world through Drainable::getState()) could be used to determine 6710910Sandreas.sandberg@arm.com * if all objects have entered the Drained state, the protocol is 6810910Sandreas.sandberg@arm.com * actually a bit more elaborate. See Drainable::drain() for details. 6910910Sandreas.sandberg@arm.com */ 7010910Sandreas.sandberg@arm.comenum class DrainState { 7110910Sandreas.sandberg@arm.com Running, /** Running normally */ 7210910Sandreas.sandberg@arm.com Draining, /** Draining buffers pending serialization/handover */ 7310910Sandreas.sandberg@arm.com Drained /** Buffers drained, ready for serialization/handover */ 7410910Sandreas.sandberg@arm.com}; 7510910Sandreas.sandberg@arm.com#endif 769342SAndreas.Sandberg@arm.com 779342SAndreas.Sandberg@arm.com/** 789342SAndreas.Sandberg@arm.com * This class coordinates draining of a System. 799342SAndreas.Sandberg@arm.com * 8010912Sandreas.sandberg@arm.com * When draining the simulator, we need to make sure that all 8110912Sandreas.sandberg@arm.com * Drainable objects within the system have ended up in the drained 8210912Sandreas.sandberg@arm.com * state before declaring the operation to be successful. This class 8310912Sandreas.sandberg@arm.com * keeps track of how many objects are still in the process of 8410912Sandreas.sandberg@arm.com * draining. Once it determines that all objects have drained their 8510912Sandreas.sandberg@arm.com * state, it exits the simulation loop. 869342SAndreas.Sandberg@arm.com * 879342SAndreas.Sandberg@arm.com * @note A System might not be completely drained even though the 889342SAndreas.Sandberg@arm.com * DrainManager has caused the simulation loop to exit. Draining needs 899342SAndreas.Sandberg@arm.com * to be restarted until all Drainable objects declare that they don't 909342SAndreas.Sandberg@arm.com * need further simulation to be completely drained. See Drainable for 919342SAndreas.Sandberg@arm.com * more information. 929342SAndreas.Sandberg@arm.com */ 939342SAndreas.Sandberg@arm.comclass DrainManager 949342SAndreas.Sandberg@arm.com{ 9510912Sandreas.sandberg@arm.com private: 9610912Sandreas.sandberg@arm.com DrainManager(); 9710912Sandreas.sandberg@arm.com#ifndef SWIG 9810912Sandreas.sandberg@arm.com DrainManager(DrainManager &) = delete; 9910912Sandreas.sandberg@arm.com#endif 10010912Sandreas.sandberg@arm.com ~DrainManager(); 10110912Sandreas.sandberg@arm.com 1029342SAndreas.Sandberg@arm.com public: 10310912Sandreas.sandberg@arm.com /** Get the singleton DrainManager instance */ 10410912Sandreas.sandberg@arm.com static DrainManager &instance() { return _instance; } 1059342SAndreas.Sandberg@arm.com 1069342SAndreas.Sandberg@arm.com /** 10710912Sandreas.sandberg@arm.com * Try to drain the system. 1089342SAndreas.Sandberg@arm.com * 10910912Sandreas.sandberg@arm.com * Try to drain the system and return true if all objects are in a 11010912Sandreas.sandberg@arm.com * the Drained state at which point the whole simulator is in a 11110912Sandreas.sandberg@arm.com * consistent state and ready for checkpointing or CPU 11210912Sandreas.sandberg@arm.com * handover. The simulation script must continue simulating until 11310912Sandreas.sandberg@arm.com * the simulation loop returns "Finished drain", at which point 11410912Sandreas.sandberg@arm.com * this method should be called again. This cycle should continue 11510912Sandreas.sandberg@arm.com * until this method returns true. 11610912Sandreas.sandberg@arm.com * 11710912Sandreas.sandberg@arm.com * @return true if all objects were drained successfully, false if 11810912Sandreas.sandberg@arm.com * more simulation is needed. 1199342SAndreas.Sandberg@arm.com */ 12010912Sandreas.sandberg@arm.com bool tryDrain(); 1219342SAndreas.Sandberg@arm.com 12210912Sandreas.sandberg@arm.com /** 12310912Sandreas.sandberg@arm.com * Resume normal simulation in a Drained system. 12410912Sandreas.sandberg@arm.com */ 12510912Sandreas.sandberg@arm.com void resume(); 12610912Sandreas.sandberg@arm.com 12710912Sandreas.sandberg@arm.com /** 12810912Sandreas.sandberg@arm.com * Run state fixups before a checkpoint restore operation 12910912Sandreas.sandberg@arm.com * 13010912Sandreas.sandberg@arm.com * The drain state of an object isn't stored in a checkpoint since 13110912Sandreas.sandberg@arm.com * the whole system is always going to be in the Drained state 13210912Sandreas.sandberg@arm.com * when the checkpoint is created. When the checkpoint is restored 13310912Sandreas.sandberg@arm.com * at a later stage, recreated objects will be in the Running 13410912Sandreas.sandberg@arm.com * state since the state isn't stored in checkpoints. This method 13510912Sandreas.sandberg@arm.com * performs state fixups on all Drainable objects and the 13610912Sandreas.sandberg@arm.com * DrainManager itself. 13710912Sandreas.sandberg@arm.com */ 13810912Sandreas.sandberg@arm.com void preCheckpointRestore(); 13910912Sandreas.sandberg@arm.com 14010912Sandreas.sandberg@arm.com /** Check if the system is drained */ 14110912Sandreas.sandberg@arm.com bool isDrained() { return _state == DrainState::Drained; } 14210912Sandreas.sandberg@arm.com 14310912Sandreas.sandberg@arm.com /** Get the simulators global drain state */ 14410912Sandreas.sandberg@arm.com DrainState state() { return _state; } 1459342SAndreas.Sandberg@arm.com 1469342SAndreas.Sandberg@arm.com /** 1479342SAndreas.Sandberg@arm.com * Notify the DrainManager that a Drainable object has finished 1489342SAndreas.Sandberg@arm.com * draining. 1499342SAndreas.Sandberg@arm.com */ 15010912Sandreas.sandberg@arm.com void signalDrainDone(); 1519342SAndreas.Sandberg@arm.com 15210912Sandreas.sandberg@arm.com public: 15310912Sandreas.sandberg@arm.com void registerDrainable(Drainable *obj); 15410912Sandreas.sandberg@arm.com void unregisterDrainable(Drainable *obj); 15510912Sandreas.sandberg@arm.com 15610912Sandreas.sandberg@arm.com private: 1579342SAndreas.Sandberg@arm.com /** 15810912Sandreas.sandberg@arm.com * Thread-safe helper function to get the number of Drainable 15910912Sandreas.sandberg@arm.com * objects in a system. 1609342SAndreas.Sandberg@arm.com */ 16110912Sandreas.sandberg@arm.com size_t drainableCount() const; 1629342SAndreas.Sandberg@arm.com 16310912Sandreas.sandberg@arm.com /** Lock protecting the set of drainable objects */ 16410912Sandreas.sandberg@arm.com mutable std::mutex globalLock; 16510912Sandreas.sandberg@arm.com 16610912Sandreas.sandberg@arm.com /** Set of all drainable objects */ 16710912Sandreas.sandberg@arm.com std::unordered_set<Drainable *> _allDrainable; 16810912Sandreas.sandberg@arm.com 16910912Sandreas.sandberg@arm.com /** 17010912Sandreas.sandberg@arm.com * Number of objects still draining. This is flagged atomic since 17110912Sandreas.sandberg@arm.com * it can be manipulated by SimObjects living in different 17210912Sandreas.sandberg@arm.com * threads. 17310912Sandreas.sandberg@arm.com */ 17410912Sandreas.sandberg@arm.com std::atomic_uint _count; 17510912Sandreas.sandberg@arm.com 17610912Sandreas.sandberg@arm.com /** Global simulator drain state */ 17710912Sandreas.sandberg@arm.com DrainState _state; 17810912Sandreas.sandberg@arm.com 17910912Sandreas.sandberg@arm.com /** Singleton instance of the drain manager */ 18010912Sandreas.sandberg@arm.com static DrainManager _instance; 1819342SAndreas.Sandberg@arm.com}; 1829342SAndreas.Sandberg@arm.com 1839342SAndreas.Sandberg@arm.com/** 1849342SAndreas.Sandberg@arm.com * Interface for objects that might require draining before 1859342SAndreas.Sandberg@arm.com * checkpointing. 1869342SAndreas.Sandberg@arm.com * 1879342SAndreas.Sandberg@arm.com * An object's internal state needs to be drained when creating a 1889342SAndreas.Sandberg@arm.com * checkpoint, switching between CPU models, or switching between 1899342SAndreas.Sandberg@arm.com * timing models. Once the internal state has been drained from 19010912Sandreas.sandberg@arm.com * <i>all</i> objects in the simulator, the objects are serialized to 1919342SAndreas.Sandberg@arm.com * disc or the configuration change takes place. The process works as 1929342SAndreas.Sandberg@arm.com * follows (see simulate.py for details): 1939342SAndreas.Sandberg@arm.com * 1949342SAndreas.Sandberg@arm.com * <ol> 1959342SAndreas.Sandberg@arm.com * <li>Call Drainable::drain() for every object in the 1969342SAndreas.Sandberg@arm.com * system. Draining has completed if all of them return 1979342SAndreas.Sandberg@arm.com * zero. Otherwise, the sum of the return values is loaded into 1989342SAndreas.Sandberg@arm.com * the counter of the DrainManager. A pointer to the drain 1999342SAndreas.Sandberg@arm.com * manager is passed as an argument to the drain() method. 2009342SAndreas.Sandberg@arm.com * 2019342SAndreas.Sandberg@arm.com * <li>Continue simulation. When an object has finished draining its 20210912Sandreas.sandberg@arm.com * internal state, it calls DrainManager::signalDrainDone() on the 20310912Sandreas.sandberg@arm.com * manager. When the counter in the manager reaches zero, the 20410912Sandreas.sandberg@arm.com * simulation stops. 2059342SAndreas.Sandberg@arm.com * 2069342SAndreas.Sandberg@arm.com * <li>Check if any object still needs draining, if so repeat the 2079342SAndreas.Sandberg@arm.com * process above. 2089342SAndreas.Sandberg@arm.com * 2099342SAndreas.Sandberg@arm.com * <li>Serialize objects, switch CPU model, or change timing model. 2109342SAndreas.Sandberg@arm.com * 2119342SAndreas.Sandberg@arm.com * <li>Call Drainable::drainResume() and continue the simulation. 2129342SAndreas.Sandberg@arm.com * </ol> 2139342SAndreas.Sandberg@arm.com * 2149342SAndreas.Sandberg@arm.com */ 2159342SAndreas.Sandberg@arm.comclass Drainable 2169342SAndreas.Sandberg@arm.com{ 21710912Sandreas.sandberg@arm.com friend class DrainManager; 21810912Sandreas.sandberg@arm.com 2199342SAndreas.Sandberg@arm.com public: 2209342SAndreas.Sandberg@arm.com Drainable(); 2219342SAndreas.Sandberg@arm.com virtual ~Drainable(); 2229342SAndreas.Sandberg@arm.com 2239342SAndreas.Sandberg@arm.com /** 2249342SAndreas.Sandberg@arm.com * Determine if an object needs draining and register a 2259342SAndreas.Sandberg@arm.com * DrainManager. 2269342SAndreas.Sandberg@arm.com * 2279342SAndreas.Sandberg@arm.com * When draining the state of an object, the simulator calls drain 2289342SAndreas.Sandberg@arm.com * with a pointer to a drain manager. If the object does not need 2299342SAndreas.Sandberg@arm.com * further simulation to drain internal buffers, it switched to 2309342SAndreas.Sandberg@arm.com * the Drained state and returns 0, otherwise it switches to the 2319342SAndreas.Sandberg@arm.com * Draining state and returns the number of times that it will 2329342SAndreas.Sandberg@arm.com * call Event::process() on the drain event. Most objects are 2339342SAndreas.Sandberg@arm.com * expected to return either 0 or 1. 2349342SAndreas.Sandberg@arm.com * 2359342SAndreas.Sandberg@arm.com * @note An object that has entered the Drained state can be 2369342SAndreas.Sandberg@arm.com * disturbed by other objects in the system and consequently be 2379342SAndreas.Sandberg@arm.com * forced to enter the Draining state again. The simulator 2389342SAndreas.Sandberg@arm.com * therefore repeats the draining process until all objects return 2399342SAndreas.Sandberg@arm.com * 0 on the first call to drain(). 2409342SAndreas.Sandberg@arm.com * 2419342SAndreas.Sandberg@arm.com * @param drainManager DrainManager to use to inform the simulator 2429342SAndreas.Sandberg@arm.com * when draining has completed. 2439342SAndreas.Sandberg@arm.com * 2449342SAndreas.Sandberg@arm.com * @return 0 if the object is ready for serialization now, >0 if 2459342SAndreas.Sandberg@arm.com * it needs further simulation. 2469342SAndreas.Sandberg@arm.com */ 2479342SAndreas.Sandberg@arm.com virtual unsigned int drain(DrainManager *drainManager) = 0; 2489342SAndreas.Sandberg@arm.com 2499342SAndreas.Sandberg@arm.com /** 2509342SAndreas.Sandberg@arm.com * Resume execution after a successful drain. 2519342SAndreas.Sandberg@arm.com * 2529342SAndreas.Sandberg@arm.com * @note This method is normally only called from the simulation 2539342SAndreas.Sandberg@arm.com * scripts. 2549342SAndreas.Sandberg@arm.com */ 2559342SAndreas.Sandberg@arm.com virtual void drainResume(); 2569342SAndreas.Sandberg@arm.com 25710910Sandreas.sandberg@arm.com DrainState getDrainState() const { return _drainState; } 2589342SAndreas.Sandberg@arm.com 2599342SAndreas.Sandberg@arm.com protected: 26010910Sandreas.sandberg@arm.com void setDrainState(DrainState new_state) { _drainState = new_state; } 2619342SAndreas.Sandberg@arm.com 2629342SAndreas.Sandberg@arm.com private: 26310912Sandreas.sandberg@arm.com DrainManager &_drainManager; 26410910Sandreas.sandberg@arm.com DrainState _drainState; 2659342SAndreas.Sandberg@arm.com}; 2669342SAndreas.Sandberg@arm.com 2679342SAndreas.Sandberg@arm.com#endif 268