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Diffstat (limited to 'src/sim/dvfs_handler.hh')
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1 files changed, 230 insertions, 0 deletions
diff --git a/src/sim/dvfs_handler.hh b/src/sim/dvfs_handler.hh new file mode 100644 index 000000000..ba8ed3e8e --- /dev/null +++ b/src/sim/dvfs_handler.hh @@ -0,0 +1,230 @@ +/* + * Copyright (c) 2013-2014 ARM Limited + * All rights reserved + * + * The license below extends only to copyright in the software and shall + * not be construed as granting a license to any other intellectual + * property including but not limited to intellectual property relating + * to a hardware implementation of the functionality of the software + * licensed hereunder. You may use the software subject to the license + * terms below provided that you ensure that this notice is replicated + * unmodified and in its entirety in all distributions of the software, + * modified or unmodified, in source code or in binary form. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer; + * redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution; + * neither the name of the copyright holders nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * Authors: Vasileios Spiliopoulos + * Akash Bagdia + * Stephan Diestelhorst + */ + +/** + * @file + * DVFSHandler and DomainConfig class declaration used for managing voltage + * and frequency scaling of the various DVFS domains in the system (with each + * domain having their independent domain configuration information) + */ + + +#ifndef __SIM_DVFS_HANDLER_HH__ +#define __SIM_DVFS_HANDLER_HH__ + +#include <vector> + +#include "params/ClockDomain.hh" +#include "params/DVFSHandler.hh" +#include "params/VoltageDomain.hh" +#include "sim/clock_domain.hh" +#include "sim/eventq.hh" +#include "sim/sim_object.hh" + + +/** + * DVFS Handler class, maintains a list of all the domains it can handle. + * Each entry of that list is an object of the DomainConfig class, and the + * handler uses the methods provided by that class to get access to the + * configuration of each domain. The handler is responsible for setting/getting + * clock periods and voltages from clock/voltage domains. + * The handler acts the bridge between software configurable information + * for each domain as provided to the controller and the hardware + * implementation details for those domains. + */ +class DVFSHandler : public SimObject +{ + public: + typedef DVFSHandlerParams Params; + DVFSHandler(const Params *p); + + typedef SrcClockDomain::DomainID DomainID; + typedef SrcClockDomain::PerfLevel PerfLevel; + + /** + * Check whether a domain ID is known to the handler or not. + * @param domain_id Domain ID to check + * @return Domain ID known to handler? + */ + bool validDomainID(DomainID domain_id) const; + + /** + * Get transition latency to switch between performance levels. + * @return Transition latency + */ + Tick transLatency() const { return _transLatency; } + + /** + * Set a new performance level for the specified domain. The actual update + * will be delayed by transLatency(). + * + * @param domain_id Software visible ID of the domain to be configured + * @param perf_level Requested performance level (0 - fast, >0 slower) + * @return status whether the setting was successful + */ + bool perfLevel(DomainID domain_id, PerfLevel perf_level); + + /** + * Get the current performance level of a domain. While a change request is + * in-flight, will return the current (i.e. old, unmodified) value. + * + * @param domain_id Domain ID to query + * @return Current performance level of the specified domain + */ + PerfLevel perfLevel(DomainID domain_id) const { + assert(isEnabled()); + return findDomain(domain_id)->perfLevel(); + } + + /** + * Read the clock period of the specified domain at the specified + * performance level. + * @param domain_id Domain ID to query + * @param perf_level Performance level of interest + * @return Clock period in ticks for the requested performance level of + * the respective domain + */ + Tick clkPeriodAtPerfLevel(DomainID domain_id, PerfLevel perf_level) const + { + return findDomain(domain_id)->clkPeriodAtPerfLevel(perf_level); + } + + /** + * Get the total number of available performance levels. + * + * @param domain_id Domain ID to query + * @return Number of performance levels that where configured for the + * respective domain + */ + PerfLevel numPerfLevels(PerfLevel domain_id) const + { + return findDomain(domain_id)->numPerfLevels(); + } + + /** + * Check enable status of the DVFS handler, when the handler is disabled, no + * request should be sent to the handler. + * @return True, if the handler is enabled + */ + bool isEnabled() const { return enableHandler; } + + void serialize(std::ostream &os); + void unserialize(Checkpoint *cp, const std::string §ion); + + private: + typedef std::map<DomainID, SrcClockDomain*> Domains; + Domains domains; + + /** + * Clock domain of the system the handler is instantiated. + */ + SrcClockDomain* sysClkDomain; + + /** + * Search for a domain based on the domain ID. + * + * @param domain_id Domain ID to search for + * @return Pointer to the source clock domain with matching ID. + */ + SrcClockDomain *findDomain(DomainID domain_id) const { + auto it = domains.find(domain_id); + panic_if(it == domains.end(), + "DVFS: Could not find a domain for ID %d.\n",domain_id ); + return domains.find(domain_id)->second; + } + + /** + * Disabling the DVFS handler ensures that all the DVFS migration requests + * are ignored. Domains remain at their default frequency and voltage. + */ + bool enableHandler; + + + /** + * This corresponds to the maximum transition latency associated with the + * hardware transitioning from a particular performance level to the other + */ + const Tick _transLatency; + + + + /** + * Update performance level event, encapsulates all the required information + * for a future call to change a domain's performance level. + */ + struct UpdateEvent : public Event { + UpdateEvent() : Event(DVFS_Update_Pri) {} + + /** + * Static pointer to the single DVFS hander for all the update events + */ + static DVFSHandler *dvfsHandler; + + /** + * ID of the domain that will be changed by the in-flight event + */ + DomainID domainIDToSet; + + /** + * Target performance level of the in-flight event + */ + PerfLevel perfLevelToSet; + + /** + * Updates the performance level by modifying the clock and the voltage + * of the associated clocked objects. Gets information from + * domainIDToSet and perfLevelToSet for easier calling through an + * event. + */ + void updatePerfLevel(); + + void process() { updatePerfLevel(); } + }; + + typedef std::map<DomainID, UpdateEvent> UpdatePerfLevelEvents; + /** + * Map from domain IDs -> perf level update events, records in-flight change + * requests per domain ID. + */ + UpdatePerfLevelEvents updatePerfLevelEvents; +}; + +#endif // __SIM_DVFS_HANDLER_HH__ |