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2013-06-27sim: Add the notion of clock domains to all ClockedObjectsAkash Bagdia
This patch adds the notion of source- and derived-clock domains to the ClockedObjects. As such, all clock information is moved to the clock domain, and the ClockedObjects are grouped into domains. The clock domains are either source domains, with a specific clock period, or derived domains that have a parent domain and a divider (potentially chained). For piece of logic that runs at a derived clock (a ratio of the clock its parent is running at) the necessary derived clock domain is created from its corresponding parent clock domain. For now, the derived clock domain only supports a divider, thus ensuring a lower speed compared to its parent. Multiplier functionality implies a PLL logic that has not been modelled yet (create a separate clock instead). The clock domains should be used as a mechanism to provide a controllable clock source that affects clock for every clocked object lying beneath it. The clock of the domain can (in a future patch) be controlled by a handler responsible for dynamic frequency scaling of the respective clock domains. All the config scripts have been retro-fitted with clock domains. For the System a default SrcClockDomain is created. For CPUs that run at a different speed than the system, there is a seperate clock domain created. This domain incorporates the CPU and the associated caches. As before, Ruby runs under its own clock domain. The clock period of all domains are pre-computed, such that no virtual functions or multiplications are needed when calling clockPeriod. Instead, the clock period is pre-computed when any changes occur. For this to be possible, each clock domain tracks its children.
2013-06-27config: Remove redundant explicit setting of default clocksAkash Bagdia
This patch removes the explicit setting of the clock period for certain instances of CoherentBus, NonCoherentBus and IOCache where the specified clock is same as the default value of the system clock. As all the values used are the defaults, there are no performance changes. There are similar cases where the toL2Bus is set to use the parent CPU clock which is already the default behaviour. The main motivation for these simplifications is to ease the introduction of clock domains.
2013-06-27cpu: Consider instructions waiting for FU completion in drainingAndreas Hansson
This patch changes the IEW drain check to include the FU pool as there can be instructions that are "stored" in FU completion events and thus not covered by the existing checks. With this patch, we simply include a check to see if all the FUs are considered non-busy in the next tick. Without this patch, the pc-switcheroo-full regression fails after minor changes to the cache timing (aligning to clock edge).
2013-06-18kvm: Use the address finalization code in the TLBAndreas Sandberg
Reuse the address finalization code in the TLB instead of replicating it when handling MMIO. This patch also adds support for injecting memory mapped IPR requests into the memory system.
2013-06-11kvm: Add more VM statsAndreas Sandberg
This changeset adds the following stats to KVM: * numVMHalfEntries: Number of entries into KVM to finalize pending IO operations without executing guest instructions. These typically happen as a result of a drain where the guest must finalize some operations before the guest state is consistent. * numExitSignal: Number of VM exits that have been triggered by a signal. These usually happen as a result of the timer that limits the time spent in KVM.
2013-06-11kvm: Separate host frequency from simulated CPU frequencyAndreas Sandberg
We used to use the KVM CPU's clock to specify the host frequency. This was not ideal for several reasons. One of them being that the clock parameter of a CPU determines the frequency of some of the components connected to the CPU. This changeset adds a separate hostFreq parameter that should be used to specify the host frequency until we add code to autodetect it. The hostFactor should still be used to specify the conversion factor between the host performance and that of the simulated system.
2013-06-11kvm: Don't handle IO and execute in the same tickAndreas Sandberg
We currently execute instructions in the guest and then handle any IO request right after we break out of the virtualized environment. This has the effect of executing IO requests in the exact same tick as the first instruction in the sequence that was just run. There seem to be cases where this simplification upsets some timing-sensitive devices. This changeset splits execute and IO (and other services) across multiple ticks. This is implemented by adding a separate RunningService state to the CPU state machine. When a VM requires service, it enters into this state and pending IO is then serviced in the future instead of immediately. The delay between getting the request and servicing it depends on the number of cycles executed in the guest, which allows other components to catch up with the CPU.
2013-06-11kvm: Maintain a local instruction counter and update totalNumInstsAndreas Sandberg
Update the system's totalNumInst counter when exiting from KVM and maintain an internal absolute instruction count instead of relying on the one from perf.
2013-06-11cpu: Add support for scheduling multiple inst/load stop eventsAndreas Sandberg
Currently, the only way to get a CPU to stop after a fixed number of instructions/loads is to set a property on the CPU that causes a SimLoopExitEvent to be scheduled when the CPU is constructed. This is clearly not ideal in cases where the simulation script wants the CPU to stop at multiple instruction counts (e.g., SimPoint generation). This changeset adds the methods scheduleInstStop() and scheduleLoadStop() to the BaseCPU. These methods are exported to Python and are designed to be used from the simulation script. By using these methods instead of the old properties, a simulation script can schedule a stop at any point during simulation or schedule multiple stops. The number of instructions specified when scheduling a stop is relative to the current point of execution.
2013-06-03kvm: Allow architectures to override the cycle accounting mechanismAndreas Sandberg
Some architectures have special registers in the guest that can be used to do cycle accounting. This is generally preferrable since the prevents the guest from seeing a non-monotonic clock. This changeset adds a virtual method, getHostCycles(), that the architecture-specific code can override to implement this functionallity. The default implementation uses the hwCycles counter.
2013-06-03kvm: Add handling of EAGAIN when creating timersAndreas Sandberg
timer_create can apparently return -1 and set errno to EAGAIN if the kernel suffered a temporary failure when allocating a timer. This happens from time to time, so we need to handle it.
2013-06-03kvm: Add a call to thread->startup() in startup()Andreas Sandberg
It is now required to initialize the thread context by calling startup() on it. Failing to do so currently causes decoder in x86-based CPUs to get very confused when restoring from checkpoints.
2013-05-30cpu: Prune the stale TraceCPUAndreas Hansson
This patch prunes the TraceCPU as the code is stale and the functionality that it provided can now be achieved with the TrafficGen using its trace playback mode. The TraceCPU was able to play back pre-recorded memory traces of a few different formats, and to achieve this level of flexibility with the TrafficGen, use the util/encode_packet_trace (with suitable modifications) to create a protobuf trace off-line.
2013-05-30cpu: Check that minimum TrafficGen period is less than max periodSascha Bischoff
Add a check which ensures that the minumum period for the LINEAR and RANDOM traffic generator states is less than or equal to the maximum period. If the minimum period is greater than the maximum period a fatal is triggered.
2013-05-30cpu: Fix bug when reading in TrafficGen state transitionsSascha Bischoff
This patch fixes a bug with the traffic generator which occured when reading in the state transitions from the configuration file. Previously, the size of the vector which stored the transitions was used to get the size of the transitions matrix, rather than using the number of states. Therefore, if there were more transitions than states, i.e. some transitions has a probability of less than 1, then the traffic generator would fatal when trying to check the transitions. This issue has been addressed by using the number of input states, rather then the number of transitions.
2013-05-30cpu: Add request elasticity to the traffic generatorAndreas Hansson
This patch adds an optional request elasticity to the traffic generator, effectievly compensating for it in the case of the linear and random generators, and adding it in the case of the trace generator. The accounting is left with the top-level traffic generator, and the individual generators do the necessary math as part of determining the next packet tick. Note that in the linear and random generators we have to compensate for the blocked time to not be elastic, i.e. without this patch the aforementioned generators will slow down in the case of back-pressure.
2013-05-30cpu: Block traffic generator when requests have to retryAndreas Hansson
This patch changes the queued port for a conventional master port and stalls the traffic generator when requests are not immediately accepted. This is a first step to allowing elasticity in the injection of requests. The patch also adds stats for the sent packets and retries, and slightly changes how the nextPacketTick and getNextPacket interact. The advancing of the trace is now moved to getNextPacket and nextPacketTick is only responsible for answering the question when the next packet should be sent.
2013-05-30cpu: Move traffic generator sending out of generator statesAndreas Hansson
This patch moves the responsibility for sending packets out of the generator states and leaves it with the top-level traffic generator. The main aim of this patch is to enable a transition to non-queued ports, i.e. with send/retry flow control, and to do so it is much more convenient to not wrap the port interactions and instead leave it all local to the traffic generator. The generator states now only govern when they are ready to send something new, and the generation of the packets to send. They thus have no knowledge of the port that is used.
2013-05-30cpu: Fold together the StateGraph and the TrafficGenAndreas Hansson
This patch simplifies the object hierarchy of the traffic generator by getting rid of the StateGraph class and folding this functionality into the traffic generator itself. The main goal of this patch is to facilitate upcoming changes by reducing the number of affected layers.
2013-05-30cpu: Make hash struct instead of class to please clangAndreas Hansson
This patch changes the type of the hash function for BasicBlockRanges to match the original definition of the templatized type. Without this, clang raises a warning and combined with the "-Werror" flag this causes compilation to fail.
2013-05-14cpu: remove local/globalHistoryBits params from branch predAnthony Gutierrez
having separate params for the local/globalHistoryBits and the local/globalPredictorSize can lead to inconsistencies if they are not carefully set. this patch dervies the number of bits necessary to index into the local/global predictors based on their size. the value of the localHistoryTableSize for the ARM O3 CPU has been increased to 1024 from 64, which is more accurate for an A15 based on some correlation against A15 hardware.
2013-05-14kvm: Add support for disabling coalesced MMIOAndreas Sandberg
Add the option useCoalescedMMIO to the BaseKvmCPU. The default behavior is to disable coalesced MMIO since this hasn't been heavily tested.
2013-05-14kvm: Dump state before panic in KVM exit handlersAndreas Sandberg
2013-05-14kvm: Fix the memory interface used by KVMAndreas Sandberg
The CpuPort class was removed before the KVM patches were committed, which means that the KVM interface currently doesn't compile. This changeset adds the BaseKvmCPU::KVMCpuPort class which derives from MasterPort. This class is used on the data and instruction ports instead of the old CpuPort.
2013-05-02kvm: Add a stat counting number of instructions executedAndreas Sandberg
This changeset adds a 'numInsts' stat to the KVM-based CPU. It also cleans up the variable names in kvmRun to make the distinction between host cycles and estimated simulated cycles clearer. As a bonus feature, it also fixes a warning (unreferenced variable) when compiling in fast mode.
2013-05-02kvm: Add checkpoint debug printAndreas Sandberg
Add a debug print (when the Checkpoint debug flag is set) on serialize and unserialize. Additionally, dump the KVM state before serializing. The KVM state isn't dumped after unserializing since the state is loaded lazily on the next KVM entry.
2013-05-02kvm: Make MMIO requests uncacheableAndreas Sandberg
Device accesses are normally uncacheable. This change probably doesn't make any difference since we normally disable caching when KVM is active. However, there might be devices that check this, so we'd better enable this flag to be safe.
2013-04-23cpu: Fix TraceGen flag initalisationAndreas Hansson
This patch ensures the flags are always initialised.
2013-04-22cpu: Use request flags in trace playbackAndreas Hansson
This patch changes the TraceGen such that it uses the optional request flags from the protobuf trace if they are present.
2013-04-22cpu: Make the generators usable outside the TrafficGen moduleAndreas Hansson
This patch enables the use of the generator behaviours outside the TrafficGen module. This is useful e.g. to allow packet replay modes for other devices in the system without having to replace them with a TrafficGen in the configuration files. This change also enables more specific behaviours to be composed as specific modules, e.g. BaseBandModem can use a number of generators and have application-specific parameters based around a specific set of generators.
2013-04-22kvm: Add support for pseudo-ops on ARMAndreas Sandberg
This changeset adds support for m5 pseudo-ops when running in kvm-mode. Unfortunately, we can't trap the normal gem5 co-processor entry in KVM (it doesn't seem to be possible to trap accesses to non-existing co-processors). We therefore use BZJ instructions to cause a trap from virtualized mode into gem5. The BZJ instruction is becomes a normal branch to the gem5 fallback code when running in simulated mode, which means that this patch does not need to change the ARM ISA-specific code. Note: This requires a patched host kernel.
2013-04-22kvm: Add support for state dumping on ARMAndreas Sandberg
2013-04-22kvm: Add basic support for ARMAndreas Sandberg
Architecture specific limitations: * LPAE is currently not supported by gem5. We therefore panic if LPAE is enabled when returning to gem5. * The co-processor based interface to the architected timer is unsupported. We can't support this due to limitations in the KVM API on ARM. * M5 ops are currently not supported. This requires either a kernel hack or a memory mapped device that handles the guest<->m5 interface.
2013-04-22kvm: Add experimental support for a perf-based execution timerAndreas Sandberg
Add support for using the CPU cycle counter instead of a normal POSIX timer to generate timed exits to gem5. This should, in theory, provide better resolution when requesting timer signals. The perf-based timer requires a fairly recent kernel since it requires a working PERF_EVENT_IOC_PERIOD ioctl. This ioctl has existed in the kernel for a long time, but it used to be completely broken due to an inverted match when the kernel copied things from user space. Additionally, the ioctl does not change the sample period correctly on all kernel versions which implement it. It is currently only known to work reliably on kernel version 3.7 and above on ARM.
2013-04-22kvm: Avoid synchronizing the TC on every KVM exitAndreas Sandberg
Reduce the number of KVM->TC synchronizations by overloading the getContext() method and only request an update when the TC is requested as opposed to every time KVM returns to gem5.
2013-04-22kvm: Basic support for hardware virtualized CPUsAndreas Sandberg
This changeset introduces the architecture independent parts required to support KVM-accelerated CPUs. It introduces two new simulation objects: KvmVM -- The KVM VM is a component shared between all CPUs in a shared memory domain. It is typically instantiated as a child of the system object in the simulation hierarchy. It provides access to KVM VM specific interfaces. BaseKvmCPU -- Abstract base class for all KVM-based CPUs. Architecture dependent CPU implementations inherit from this class and implement the following methods: * updateKvmState() -- Update the architecture-dependent KVM state from the gem5 thread context associated with the CPU. * updateThreadContext() -- Update the thread context from the architecture-dependent KVM state. * dump() -- Dump the KVM state using (optional). In order to deliver interrupts to the guest, CPU implementations typically override the tick() method and check for, and deliver, interrupts prior to entering KVM. Hardware-virutalized CPU currently have the following limitations: * SE mode is not supported. * PC events are not supported. * Timing statistics are currently very limited. The current approach simply scales the host cycles with a user-configurable factor. * The simulated system must not contain any caches. * Since cycle counts are approximate, there is no way to request an exact number of cycles (or instructions) to be executed by the CPU. * Hardware virtualized CPUs and gem5 CPUs must not execute at the same time in the same simulator instance. * Only single-CPU systems can be simulated. * Remote GDB connections to the guest system are not supported. Additionally, m5ops requires an architecture specific interface and might not be supported.
2013-04-22cpu: Let python scripts obtain the number of instructions executedTimothy M. Jones
2013-04-22arm: Enable support for triggering a sim panic on kernel panicsAndreas Sandberg
Add the options 'panic_on_panic' and 'panic_on_oops' to the LinuxArmSystem SimObject. When these option are enabled, the simulator panics when the guest kernel panics or oopses. Enable panic on panic and panic on oops in ARM-based test cases.
2013-04-22sim: separate nextCycle() and clockEdge() in clockedObjectsDam Sunwoo
Previously, nextCycle() could return the *current* cycle if the current tick was already aligned with the clock edge. This behavior is not only confusing (not quite what the function name implies), but also caused problems in the drainResume() function. When exiting/re-entering the sim loop (e.g., to take checkpoints), the CPUs will drain and resume. Due to the previous behavior of nextCycle(), the CPU tick events were being rescheduled in the same ticks that were already processed before draining. This caused divergence from runs that did not exit/re-entered the sim loop. (Initially a cycle difference, but a significant impact later on.) This patch separates out the two behaviors (nextCycle() and clockEdge()), uses nextCycle() in drainResume, and uses clockEdge() everywhere else. Nothing (other than name) should change except for the drainResume timing.
2013-04-22cpu: generate SimPoint basic block vector profilesDam Sunwoo
This patch is based on http://reviews.m5sim.org/r/1474/ originally written by Mitch Hayenga. Basic block vectors are generated (simpoint.bb.gz in simout folder) based on start and end addresses of basic blocks. Some comments to the original patch are addressed and hooks are added to create and resume from checkpoints based on instruction counts dictated by external SimPoint analysis tools. SimPoint creation/resuming options will be implemented as a separate patch.
2013-04-22cpu: fix a switching issue with the o3 cpu.Ali Saidi
This change fixes the switcheroo test that broke earlier this month. The code that was checking for the pipeline being blocked wasn't checking for a pending translation, only for a icache access.
2013-03-29o3cpu: commit: changes interrupt handlingNilay Vaish
Currently the commit stage keeps a local copy of the interrupt object. Since the interrupt is usually handled several cycles after the commit stage becomes aware of it, it is possible that the local copy of the interrupt object may not be the interrupt that is actually handled. It is possible that another interrupt occurred in the interval between interrupt detection and interrupt handling. This patch creates a copy of the interrupt just before the interrupt is handled. The local copy is ignored.
2013-03-26cpu: Remove CpuPort and use MasterPort in the CPU classesAndreas Hansson
This patch changes the port in the CPU classes to use MasterPort instead of the derived CpuPort. The functions of the CpuPort are now distributed across the relevant subclasses. The port accessor functions (getInstPort and getDataPort) now return a MasterPort instead of a CpuPort. This simplifies creating derivative CPUs that do not use the CpuPort.
2013-03-20cpu: Avoid including inorder TLBUnit to avoid gcc LTO bugAndreas Hansson
This patch comments out the inclusion of the inorder TLBUnit which is only used in the 9-stage pipeline. With the TLBUnit present, gcc >= 4.6 in combination with LTO ends up throwing away the definition of the TLBUnit destructor, and consequently fail to link. See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53808 for more details about the bug, and http://gcc.gnu.org/ml/gcc/2012-06/msg00397.html for the discussion thread that also touches on similar issues seen with clang.
2013-03-12cpu: Fix state transition bug in the traffic generatorAndreas Sandberg
The traffic generator used to incorrectly determine the next state in when state 0 had a non-zero probability. Due to the way the next transition was determined, state 0 could never be entered other than as an initial state. This changeset updates the transitition() method to correctly handle such cases and cases where the transition matrix is a 1x1 matrix.
2013-03-04cpu: fix a switching issue with the o3 cpu.Ali Saidi
This change fixes the switcheroo test that broke earlier this month. The code that was checking for the pipeline being blocked wasn't checking for a pending translation, only for a icache access.
2013-02-19scons: Fix warnings issued by clang 3.2svn (XCode 4.6)Andreas Hansson
This patch fixes the warnings that clang3.2svn emit due to the "-Wall" flag. There is one case of an uninitialised value in the ARM neon ISA description, and then a whole range of unused private fields that are pruned.
2013-02-19scons: Add warning for missing declarationsAndreas Hansson
This patch enables warnings for missing declarations. To avoid issues with SWIG-generated code, the warning is only applied to non-SWIG code.
2013-02-19scons: Fix up numerous warnings about name shadowingAndreas Hansson
This patch address the most important name shadowing warnings (as produced when using gcc/clang with -Wshadow). There are many locations where constructor parameters and function parameters shadow local variables, but these are left unchanged.
2013-02-19x86: Move APIC clock divider to PythonAndreas Hansson
This patch moves the 16x APIC clock divider to the Python code to avoid the post-instantiation modifications to the clock. The x86 APIC was the only object setting the clock after creation time and this required some custom functionality and configuration. With this patch, the clock multiplier is moved to the Python code and the objects are instantiated with the appropriate clock.