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2014-05-31style: eliminate equality tests with true and falseSteve Reinhardt
Using '== true' in a boolean expression is totally redundant, and using '== false' is pretty verbose (and arguably less readable in most cases) compared to '!'. It's somewhat of a pet peeve, perhaps, but I had some time waiting for some tests to run and decided to clean these up. Unfortunately, SLICC appears not to have the '!' operator, so I had to leave the '== false' tests in the SLICC code.
2014-05-23cpu: o3: remove stat totalCommittedInstsNilay Vaish
This patch removes the stat totalCommittedInsts. This variable was used for recording the total number of instructions committed across all the threads of a core. The instructions committed by each thread are recorded invidually. The total would now be generated by summing these individual counts.
2014-05-09cpu: add more instruction mix statisticsCurtis Dunham
For the o3, add instruction mix (OpClass) histogram at commit (stats also already collected at issue). For the simple CPUs we add a histogram of executed instructions
2014-05-09cpu, arm: Allow the specification of a socket fieldAkash Bagdia
Allow the specification of a socket ID for every core that is reflected in the MPIDR field in ARM systems. This allows studying multi-socket / cluster systems with ARM CPUs.
2014-04-01cpu: Fix case where o3 lsq could print out uninitialized dataMitch Hayenga
In the O3 LSQ, data read/written is printed out in DPRINTFs. However, the data field is treated as a character string with a null terminated. However the data field is not encoded this way. This patch removes that possibility by removing the data part of the print.
2014-04-23cpu: Add O3 CPU width checksDam Sunwoo
O3CPU has a compile-time maximum width set in o3/impl.hh, but checking the configuration against this limit was not implemented anywhere except for fetch. Configuring a wider pipe than the limit can silently cause various issues during the simulation. This patch adds the proper checking in the constructor of the various pipeline stages.
2014-04-19o3: Fix occupancy checks for SMTFaissal Sleiman
A number of calls to isEmpty() and numFreeEntries() should be thread-specific. In cpu.cc, the fact that tid is /*commented*/ out is a bug. Say the rob has instructions from thread 0 (isEmpty() returns false), and none from thread 1. If we are trying to squash all of thread 1, then readTailInst(thread 1) will be called because rob->isEmpty() returns false. The result is end_it is not in the list and the while statement loops indefinitely back over the cpu's instList. In iew_impl.hh, all threads are told they have the entire remaining IQ, when each thread actually has a certain allocation. The result is extra stalls at the iew dispatch stage which the rename stage usually takes care of. In commit_impl.hh, rob->readHeadInst(thread 1) can be called if the rob only contains instructions from thread 0. This returns a dummyInst (which may work since we are trying to squash all instructions, but hardly seems like the right way to do it). In rob_impl.hh this fix skips the rest of the function more frequently and is more efficient. Committed by: Nilay Vaish <nilay@cs.wisc.edu>
2014-03-25cpu: o3: lsq: Fix TSO implementationMarco Elver
This patch fixes violation of TSO in the O3CPU, as all loads must be ordered with all other loads. In the LQ, if a snoop is observed, all subsequent loads need to be squashed if the system is TSO. Prior to this patch, the following case could be violated: P0 | P1 ; MOV [x],mail=/usr/spool/mail/nilay | MOV EAX,[y] ; MOV [y],mail=/usr/spool/mail/nilay | MOV EBX,[x] ; exists (1:EAX=1 /\ 1:EBX=0) [is a violation] The problem was found using litmus [http://diy.inria.fr]. Committed by: Nilay Vaish <nilay@cs.wisc.edu
2014-03-12alpha: Small removal of dead comments/code from alpha ISAPaul Rosenfeld
Committed by: Nilay Vaish <nilay@cs.wisc.edu>
2014-03-07cpu: Make CPU and ThreadContext getters constAndreas Hansson
This patch merely tidies up the CPU and ThreadContext getters by making them const where appropriate.
2014-03-07scons: Fixes uninitialized warnings issued by clangMitch Hayenga
Small fixes to appease recent clang versions.
2014-01-24checker: CheckerCPU handling of MiscRegs was incorrectGeoffrey Blake
The CheckerCPU model in pre-v8 code was not checking the updates to miscellaneous registers due to some methods for setting misc regs were not instrumented. The v8 patches exposed this by calling the instrumented misc reg update methods and then invoking the checker before the main CPU had updated its misc regs, leading to false positives about register mismatches. This patch fixes the non-instrumented misc reg update methods and places calls to the checker in the proper places in the O3 model.
2014-01-24arch, cpu: Add support for flattening misc register indexes.Ali Saidi
With ARMv8 support the same misc register id results in accessing different registers depending on the current mode of the processor. This patch adds the same orthogonality to the misc register file as the others (int, float, cc). For all the othre ISAs this is currently a null-implementation. Additionally, a system variable is added to all the ISA objects.
2014-01-24cpu: Add support for Memory+Barrier instruction types in O3 cpu.Giacomo Gabrielli
2014-01-24cpu: Add support for instructions that zero cache lines.Ali Saidi
2014-01-24cpu: Add CPU support for generatig wake up events when LLSC adresses are ↵Ali Saidi
snooped. This patch add support for generating wake-up events in the CPU when an address that is currently in the exclusive state is hit by a snoop. This mechanism is required for ARMv8 multi-processor support.
2014-01-24mem: per-thread cache occupancy and per-block agesDam Sunwoo
This patch enables tracking of cache occupancy per thread along with ages (in buckets) per cache blocks. Cache occupancy stats are recalculated on each stat dump.
2014-01-24base: add support for probe points and common probesMatt Horsnell
The probe patch is motivated by the desire to move analytical and trace code away from functional code. This is achieved by the probe interface which is essentially a glorified observer model. What this means to users: * add a probe point and a "notify" call at the source of an "event" * add an isolated module, that is being used to carry out *your* analysis (e.g. generate a trace) * register that module as a probe listener Note: an example is given for reference in src/cpu/o3/simple_trace.[hh|cc] and src/cpu/SimpleTrace.py What is happening under the hood: * every SimObject maintains has a ProbeManager. * during initialization (src/python/m5/simulate.py) first regProbePoints and the regProbeListeners is called on each SimObject. this hooks up the probe point notify calls with the listeners. FAQs: Why did you develop probe points: * to remove trace, stats gathering, analytical code out of the functional code. * the belief that probes could be generically useful. What is a probe point: * a probe point is used to notify upon a given event (e.g. cpu commits an instruction) What is a probe listener: * a class that handles whatever the user wishes to do when they are notified about an event. What can be passed on notify: * probe points are templates, and so the user can generate probes that pass any type of argument (by const reference) to a listener. What relationships can be generated (1:1, 1:N, N:M etc): * there isn't a restriction. You can hook probe points and listeners up in a 1:1, 1:N, N:M relationship. They become useful when a number of modules listen to the same probe points. The idea being that you can add a small number of probes into the source code and develop a larger number of useful analysis modules that use information passed by the probes. Can you give examples: * adding a probe point to the cpu's commit method allows you to build a trace module (outputting assembler), you could re-use this to gather instruction distribution (arithmetic, load/store, conditional, control flow) stats. Why is the probe interface currently restricted to passing a const reference: * the desire, initially at least, is to allow an interface to observe functionality, but not to change functionality. * of course this can be subverted by const-casting. What is the performance impact of adding probes: * when nothing is actively listening to the probes they should have a relatively minor impact. Profiling has suggested even with a large number of probes (60) the impact of them (when not active) is very minimal (<1%).
2014-01-24mem: track per-request latencies and access depths in the cache hierarchyMatt Horsnell
Add some values and methods to the request object to track the translation and access latency for a request and which level of the cache hierarchy responded to the request.
2014-01-24cpu: Relax check on squashed non-speculative instructionsAndreas Hansson
This patch relaxes the check performed when squashing non-speculative instructions, as it caused problems with loads that were marked ready, and then stalled on a blocked cache. The assertion is now allowing memory references to be non-faulting.
2013-12-03cpu: call BaseCPU startup() function in o3 cpuNilay Vaish
2013-11-15cpu: allow the fetch buffer to be smaller than a cache lineAnthony Gutierrez
the current implementation of the fetch buffer in the o3 cpu is only allowed to be the size of a cache line. some architectures, e.g., ARM, have fetch buffers smaller than a cache line, see slide 22 at: http://www.arm.com/files/pdf/at-exploring_the_design_of_the_cortex-a15.pdf this patch allows the fetch buffer to be set to values smaller than a cache line.
2013-10-31cpu: Construct ROB with cpu params struct instead of each variableFaissal Sleiman
Most other structures/stages get passed the cpu params struct.
2013-10-31cpu: Fix O3 issuse with load+barrier instructions.Ali Saidi
Fix a problem in the O3 CPU for instructions that are both memory loads and memory barriers (e.g. load acquire) and to uncacheable memory. This combination can confuse the commit stage into commitng an instruction that hasn't executed and got it's value yet. At the same time refactor the code slightly to remove duplication between two of the cases.
2013-10-17cpu: add consistent guarding to *_impl.hh files.Matt Horsnell
2013-10-17cpu: Removing an unused variable in renameFaissal Sleiman
2013-10-17cpu: Change IEW DPRINTF to use IEW debug flagFaissal Sleiman
IEW DPRINTF uses Decode debug flag, which appears to be a copying error. This patch changes this to the IEW Debug flag.
2013-10-17cpu: Put in assertions to check for maximum supported LQ/SQ sizeFaissal Sleiman
LSQSenderState represents the LQ/SQ index using uint8_t, which supports up to 256 entries (including the sentinel entry). Sending packets to memory with a higher index than 255 truncates the index, such that the response matches the wrong entry. For instance, this can result in a deadlock if a store completion does not clear the head entry.
2013-10-15arch/x86: add support for explicit CC register fileYasuko Eckert
Convert condition code registers from being specialized ("pseudo") integer registers to using the recently added CC register class. Nilay Vaish also contributed to this patch.
2013-10-15cpu: add a condition-code register classYasuko Eckert
Add a third register class for condition codes, in parallel with the integer and FP classes. No ISAs use the CC class at this point though.
2013-10-15cpu/o3: clean up rename map and free listSteve Reinhardt
Restructured rename map and free list to clean up some extraneous code and separate out common code that can be reused across different register classes (int and fp at this point). Both components now consist of a set of Simple* objects that are stand-alone rename map & free list for each class, plus a Unified* object that presents a unified interface across all register classes and then redirects accesses to the appropriate Simple* object as needed. Moved free list initialization to PhysRegFile to better isolate knowledge of physical register index mappings to that class (and remove the need to pass a number of parameters to the free list constructor). Causes a small change to these stats: cpu.rename.int_rename_lookups cpu.rename.fp_rename_lookups because they are now categorized on a per-operand basis rather than a per-instruction basis. That is, an instruction with mixed fp/int/misc operand types will have each operand categorized independently, where previously the lookup was categorized based on the instruction type.
2013-10-15cpu: rename *_DepTag constants to *_Reg_BaseSteve Reinhardt
Make these names more meaningful. Specifically, made these substitutions: s/FP_Base_DepTag/FP_Reg_Base/g; s/Ctrl_Base_DepTag/Misc_Reg_Base/g; s/Max_DepTag/Max_Reg_Index/g;
2013-10-15cpu/o3: clean up scoreboard objectSteve Reinhardt
It had a bunch of fields (and associated constructor parameters) thet it didn't really use, and the array initialization was needlessly verbose. Also just hardwired the getReg() method to aleays return true for misc regs, rather than having an array of bits that we always kept marked as ready.
2013-10-15cpu/o3: clean up physical register fileSteve Reinhardt
No need for PhysRegFile to be a template class, or have a pointer back to the CPU. Also made some methods for checking the physical register type (int vs. float) based on the phys reg index, which will come in handy later.
2013-10-15cpu: clean up architectural register classificationSteve Reinhardt
Move from a poorly documented scheme where the mapping of unified architectural register indices to register classes is hardcoded all over to one where there's an enum for the register classes and a function that encapsulates the mapping.
2013-09-11cpu: Dynamically instantiate O3 CPU LSQUnitsJoel Hestness
Previously, the LSQ would instantiate MaxThreads LSQUnits in the body of it's object, but it would only initialize numThreads LSQUnits as specified by the user. This had the effect of leaving some LSQUnits uninitialized when the number of threads was less than MaxThreads, and when adding statistics to the LSQUnit that must be initialized, this caused the stats initialization check to fail. By dynamically instantiating LSQUnits, they are all initialized and this avoids uninitialized LSQUnits from floating around during runtime.
2013-09-04cpu: Move the branch predictor out of the BaseCPUAndreas Hansson
The branch predictor is guarded by having either the in-order or out-of-order CPU as one of the available CPU models and therefore should not be used in the BaseCPU. This patch moves the parameter to the relevant CPU classes.
2013-08-19cpu: Fix a bug in the O3 CPU introduced by the cache line patchAndreas Hansson
This patch fixes a bug in the O3 fetch stage that was introduced when the cache line size was moved to the system. By mistake, the initialisation and resetting of the fetch stage was merged and put in the constructor. The resetting is now re-added where it should be.
2013-07-18mem: Set the cache line size on a system levelAndreas Hansson
This patch removes the notion of a peer block size and instead sets the cache line size on the system level. Previously the size was set per cache, and communicated through the interconnect. There were plenty checks to ensure that everyone had the same size specified, and these checks are now removed. Another benefit that is not yet harnessed is that the cache line size is now known at construction time, rather than after the port binding. Hence, the block size can be locally stored and does not have to be queried every time it is used. A follow-on patch updates the configuration scripts accordingly.
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.
2013-06-27cpu: 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).
2013-04-22sim: 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: 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.
2013-03-04cpu: 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 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.
2013-02-15cpu: Avoid duplicate entries in tracking structures for writes to misc regsGeoffrey Blake
setMiscReg currently makes a new entry for each write to a misc reg without checking for duplicates, this can cause a triggering of the assert if an instruction get replayed and writes to the same misc regs multiple times. This fix prevents duplicate entries and instead updates the value.
2013-02-15cpu: Fix rename mis-handling serializing instructions when resource constrainedGeoffrey Blake
The rename can mis-handle serializing instructions (i.e. strex) if it gets into a resource constrained situation and the serializing instruction has to be placed on the skid buffer to handle blocking. In this situation the instruction informs the pipeline it is serializing and logs that the next instruction must be serialized, but since we are blocking the pipeline defers this action to place the serializing instruction and incoming instructions into the skid buffer. When resuming from blocking, rename will pull the serializing instruction from the skid buffer and the current logic will see this as the "next" instruction that has to be serialized and because of flags set on the serializing instruction, it passes through the pipeline stage as normal and resets rename to non-serializing. This causes instructions to follow the serializing inst incorrectly and eventually leads to an error in the pipeline. To fix this rename should check first if it has to block before checking for serializing instructions.
2013-02-15o3: fix tick used for renaming and issue with range selectionMatt Horsnell
Fixes the tick used from rename: - previously this gathered the tick on leaving rename which was always 1 less than the dispatch. This conflated the decode ticks when back pressure built in the pipeline. - now picks up tick on entry. Added --store_completions flag: - will additionally display the store completion tail in the viewer. - this highlights periods when large numbers of stores are outstanding (>16 LSQ blocking) Allows selection by tick range (previously this caused an infinite loop)