summaryrefslogtreecommitdiff
path: root/src/cpu
AgeCommit message (Collapse)Author
2014-09-27arch: Use const StaticInstPtr references where possibleAndreas Hansson
This patch optimises the passing of StaticInstPtr by avoiding copying the reference-counting pointer. This avoids first incrementing and then decrementing the reference-counting pointer.
2014-09-27scons: Address issues related to gcc 4.9.1Andreas Hansson
Fix a number few minor issues to please gcc 4.9.1. Removing the '-fuse-linker-plugin' flag means no libraries are part of the LTO process, but hopefully this is an acceptable loss, as the flag causes issues on a lot of systems (only certain combinations of gcc, ld and ar work).
2014-09-27misc: Fix a bunch of minor issues identified by static analysisAndreas Hansson
Add some missing initialisation, and fix a handful benign resource leaks (including some false positives).
2014-09-20cpu: Remove unused deallocateContext callsMitch Hayenga
The call paths for de-scheduling a thread are halt() and suspend(), from the thread context. There is no call to deallocateContext() in general, though some CPUs chose to define it. This patch removes the function from BaseCPU and the cores which do not require it.
2014-09-20alpha,arm,mips,power,x86,cpu,sim: Cleanup activate/deactivateMitch Hayenga
activate(), suspend(), and halt() used on thread contexts had an optional delay parameter. However this parameter was often ignored. Also, when used, the delay was seemily arbitrarily set to 0 or 1 cycle (no other delays were ever specified). This patch removes the delay parameter and 'Events' associated with them across all ISAs and cores. Unused activate logic is also removed.
2014-09-20mem: Rename Bus to XBar to better reflect its behaviourAndreas Hansson
This patch changes the name of the Bus classes to XBar to better reflect the actual timing behaviour. The actual instances in the config scripts are not renamed, and remain as e.g. iobus or membus. As part of this renaming, the code has also been clean up slightly, making use of range-based for loops and tidying up some comments. The only changes outside the bus/crossbar code is due to the delay variables in the packet. --HG-- rename : src/mem/Bus.py => src/mem/XBar.py rename : src/mem/coherent_bus.cc => src/mem/coherent_xbar.cc rename : src/mem/coherent_bus.hh => src/mem/coherent_xbar.hh rename : src/mem/noncoherent_bus.cc => src/mem/noncoherent_xbar.cc rename : src/mem/noncoherent_bus.hh => src/mem/noncoherent_xbar.hh rename : src/mem/bus.cc => src/mem/xbar.cc rename : src/mem/bus.hh => src/mem/xbar.hh
2014-09-20cpu: Update DRAM traffic genWendy Elsasser
Add new DRAM_ROTATE mode to traffic generator. This mode will generate DRAM traffic that rotates across banks per rank, command types, and ranks per channel The looping order is illustrated below: for (ranks per channel) for (command types) for (banks per rank) // Generate DRAM Command Series This patch also adds the read percentage as an input argument to the DRAM sweep script. If the simulated read percentage is 0 or 100, the middle for loop does not generate additional commands. This loop is used only when the read percentage is set to 50, in which case the middle loop will toggle between read and write commands. Modified sweep.py script, which generates DRAM traffic. Added input arguments and support for new DRAM_ROTATE mode. The script now has input arguments for: 1) Read percentage 2) Number of ranks 3) Address mapping 4) Traffic generator mode (DRAM or DRAM_ROTATE) The default values are: 100% reads, 1 rank, RoRaBaCoCh address mapping, and DRAM traffic gen mode For the DRAM traffic mode, added multi-rank support.
2014-09-20base: Clean up redundant string functions and use C++11Andreas Hansson
This patch does a bit of housekeeping on the string helper functions and relies on the C++11 standard library where possible. It also does away with our custom string hash as an implementation is already part of the standard library.
2014-09-20cpu: Add ExecFlags debug flagMitch Hayenga
Adds a debug flag to print out the flags a instruction is tagged with.
2014-09-20cpu: use probes infrastructure to do simpoint profilingDam Sunwoo
Instead of having code embedded in cpu model to do simpoint profiling use the probes infrastructure to do it.
2014-09-19arch: Pass faults by const reference where possibleAndreas Hansson
This patch changes how faults are passed between methods in an attempt to copy as few reference-counting pointer instances as possible. This should avoid unecessary copies being created, contributing to the increment/decrement of the reference counters.
2014-09-19cpu: Use a deque in o3 rename instruction queueAndreas Hansson
Switch from a list to a data structure with better data layout.
2014-09-19misc: Use safe_cast when assumptions are made about return valueAndreas Hansson
This patch changes two dynamic_cast to safe_cast as we assume the return value is not NULL (without checking).
2014-09-12cpu: Fix memory access in Minor not setting parent Request flagsAndrew Bardsley
This patch fixes cases where uncacheable/memory type flags are not set correctly on a memory op which is split in the LSQ. Without this patch, request->request if freely used to check flags where the flags should actually come from the accumulation of request fragment flags. This patch also fixes a bug where an uncacheable access which passes through tryToSendRequest more than once can increment LSQ::numAccessesInMemorySystem more than once.
2014-09-12style: Fix line continuation, especially in debug messagesAndrew Bardsley
This patch closes a number of space gaps in debug messages caused by the incorrect use of line continuation within strings. (There's also one consistency change to a similar, but correct, use of line continuation)
2014-09-12minor: Fix typo in DPRINTF for Minor branch predictionAndreas Hansson
2014-09-09cpu: Only iterate over possible threads on the o3 cpuMitch Hayenga
Some places in O3 always iterated over "Impl::MaxThreads" even if a CPU had fewer threads. This removes a few of those instances.
2014-09-09misc: Fix a number of unitialised variables and membersAndreas Hansson
Static analysis unearther a bunch of uninitialised variables and members, and this patch addresses the problem. In all cases these omissions seem benign in the end, but at least fixing them means less false positives next time round.
2014-09-03base: Use the global Mersenne twister throughoutAndreas Hansson
This patch tidies up random number generation to ensure that it is done consistently throughout the code base. In essence this involves a clean-up of Ruby, and some code simplifications in the traffic generator. As part of this patch a bunch of skewed distributions (off-by-one etc) have been fixed. Note that a single global random number generator is used, and that the object instantiation order will impact the behaviour (the sequence of numbers will be unaffected, but if module A calles random before module B then they would obviously see a different outcome). The dependency on the instantiation order is true in any case due to the execution-model of gem5, so we leave it as is. Also note that the global ranom generator is not thread safe at this point. Regressions using the memtest, TrafficGen or any Ruby tester are affected and will be updated accordingly.
2014-05-13mem: Refactor assignment of Packet typesCurtis Dunham
Put the packet type swizzling (that is currently done in a lot of places) into a refineCommand() member function.
2014-09-03cpu: Fix o3 drain bugMitch Hayenga
For X86, the o3 CPU would get stuck with the commit stage not being drained if an interrupt arrived while drain was pending. isDrained() makes sure that pcState.microPC() == 0, thus ensuring that we are at an instruction boundary. However, when we take an interrupt we execute: pcState.upc(romMicroPC(entry)); pcState.nupc(romMicroPC(entry) + 1); tc->pcState(pcState); As a result, the MicroPC is no longer zero. This patch ensures the drain is delayed until no interrupts are present. Once draining, non-synchronous interrupts are deffered until after the switch.
2014-04-29arm: use condition code registers for ARM ISACurtis Dunham
Analogous to ee049bf (for x86). Requires a bump of the checkpoint version and corresponding upgrader code to move the condition code register values to the new register file.
2014-09-03cpu: fix bimodal predictor to use correct global history regDam Sunwoo
A small bug in the bimodal predictor caused significant degradation in performance on some benchmarks. This was caused by using the wrong globalHistoryReg during the update phase. This patches fixes the bug and brings the performance to normal level.
2014-09-03cpu: Fix cache blocked load behavior in o3 cpuMitch Hayenga
This patch fixes the load blocked/replay mechanism in the o3 cpu. Rather than flushing the entire pipeline, this patch replays loads once the cache becomes unblocked. Additionally, deferred memory instructions (loads which had conflicting stores), when replayed would not respect the number of functional units (only respected issue width). This patch also corrects that. Improvements over 20% have been observed on a microbenchmark designed to exercise this behavior.
2014-09-03cpu: Fix o3 quiesce fetch bugMitch Hayenga
O3 is supposed to stop fetching instructions once a quiesce is encountered. However due to a bug, it would continue fetching instructions from the current fetch buffer. This is because of a break statment that only broke out of the first of 2 nested loops. It should have broken out of both.
2014-09-03cpu: Fix SMT scheduling issue with the O3 cpuMitch Hayenga
The o3 cpu could attempt to schedule inactive threads under round-robin SMT mode. This is because it maintained an independent priority list of threads from the active thread list. This priority list could be come stale once threads were inactive, leading to the cpu trying to fetch/commit from inactive threads. Additionally the fetch queue is now forcibly flushed of instrctuctions from the de-scheduled thread. Relevant output: 24557000: system.cpu: [tid:1]: Calling deactivate thread. 24557000: system.cpu: [tid:1]: Removing from active threads list 24557500: system.cpu: FullO3CPU: Ticking main, FullO3CPU. 24557500: system.cpu.fetch: Running stage. 24557500: system.cpu.fetch: Attempting to fetch from [tid:1]
2014-09-03cpu: Fix incorrect speculative branch predictor behaviorMitch Hayenga
When a branch mispredicted gem5 would squash all history after and including the mispredicted branch. However, the mispredicted branch is still speculative and its history is required to rollback state if another, older, branch mispredicts. This leads to things like RAS corruption.
2014-09-03cpu: Add a fetch queue to the o3 cpuMitch Hayenga
This patch adds a fetch queue that sits between fetch and decode to the o3 cpu. This effectively decouples fetch from decode stalls allowing it to be more aggressive, running futher ahead in the instruction stream.
2014-09-03cpu: Fix o3 front-end pipeline interlock behaviorMitch Hayenga
The o3 pipeline interlock/stall logic is incorrect. o3 unnecessicarily stalled fetch and decode due to later stages in the pipeline. In general, a stage should usually only consider if it is stalled by the adjacent, downstream stage. Forcing stalls due to later stages creates and results in bubbles in the pipeline. Additionally, o3 stalled the entire frontend (fetch, decode, rename) on a branch mispredict while the ROB is being serially walked to update the RAT (robSquashing). Only should have stalled at rename.
2014-09-03cpu: Change writeback modeling for outstanding instructionsMitch Hayenga
As highlighed on the mailing list gem5's writeback modeling can impact performance. This patch removes the limitation on maximum outstanding issued instructions, however the number that can writeback in a single cycle is still respected in instToCommit().
2014-09-03arch, cpu: Factor out the ExecContext into a proper base classAndreas Sandberg
We currently generate and compile one version of the ISA code per CPU model. This is obviously wasting a lot of resources at compile time. This changeset factors out the interface into a separate ExecContext class, which also serves as documentation for the interface between CPUs and the ISA code. While doing so, this changeset also fixes up interface inconsistencies between the different CPU models. The main argument for using one set of ISA code per CPU model has always been performance as this avoid indirect branches in the generated code. However, this argument does not hold water. Booting Linux on a simulated ARM system running in atomic mode (opt/10.linux-boot/realview-simple-atomic) is actually 2% faster (compiled using clang 3.4) after applying this patch. Additionally, compilation time is decreased by 35%.
2014-09-01mem: change the namespace Message to ProtoMessageNilay Vaish
The namespace Message conflicts with the Message data type used extensively in Ruby. Since Ruby is being moved to the same Master/Slave ports based configuration style as the rest of gem5, this conflict needs to be resolved. Hence, the namespace is being renamed to ProtoMessage.
2014-09-01ruby: eliminate type TimeNilay Vaish
There is another type Time in src/base class which results in a conflict.
2014-08-13scons: Build the branch predictor for all CPUsAndreas Sandberg
The branch predictor is normally only built when a CPU that uses a branch predictor is built. The list of CPUs is currently incomplete as the simple CPUs support branch predictors (for warming, branch stats, etc). In practice, all CPU models now use branch predictors, so this changeset removes the CPU model check and replaces it with a check for the NULL ISA.
2014-08-13cpu: Don't forward declare RefCountingPtrAndreas Sandberg
RefCountingPtr is sometimes forward declared to avoid having to include refcnt.hh. This does not work since we typically return instances of RefCountingPtr rather than references to instances. The only reason this currently works is that we include refcnt.hh in cprintf.hh, which "leaks" the header to most other source files. This changeset replaces such forward declarations with an include of refcnt.hh.
2014-08-13cpu: Modernise the branch predictor (STL and C++11)Andreas Hansson
This patch does some minor house keeping of the branch predictor by adopting STL containers, and shifting some iterator to use range-based for loops. The predictor history is also changed from a list to a deque as we never to insertion/deletion other than at the front and back.
2014-08-10cpu: Ensure the traffic generator suppresses non-memory packetsAndreas Hansson
This patch adds a check to ensure that packets which are not going to a memory range are suppressed in the traffic generator. Thus, if a trace is collected in full-system, the packets destined for devices are not played back.
2014-07-23cpu: `Minor' in-order CPU modelAndrew Bardsley
This patch contains a new CPU model named `Minor'. Minor models a four stage in-order execution pipeline (fetch lines, decompose into macroops, decompose macroops into microops, execute). The model was developed to support the ARM ISA but should be fixable to support all the remaining gem5 ISAs. It currently also works for Alpha, and regressions are included for ARM and Alpha (including Linux boot). Documentation for the model can be found in src/doc/inside-minor.doxygen and its internal operations can be visualised using the Minorview tool utils/minorview.py. Minor was designed to be fairly simple and not to engage in a lot of instruction annotation. As such, it currently has very few gathered stats and may lack other gem5 features. Minor is faster than the o3 model. Sample results: Benchmark | Stat host_seconds (s) ---------------+--------v--------v-------- (on ARM, opt) | simple | o3 | minor | timing | timing | timing ---------------+--------+--------+-------- 10.linux-boot | 169 | 1883 | 1075 10.mcf | 117 | 967 | 491 20.parser | 668 | 6315 | 3146 30.eon | 542 | 3413 | 2414 40.perlbmk | 2339 | 20905 | 11532 50.vortex | 122 | 1094 | 588 60.bzip2 | 2045 | 18061 | 9662 70.twolf | 207 | 2736 | 1036
2014-06-30cpu: implement a bi-mode branch predictorAnthony Gutierrez
2014-06-21o3: make dispatch LSQ full check more selectiveBinh Pham
Dispatch should not check LSQ size/LSQ stall for non load/store instructions. This work was done while Binh was an intern at AMD Research.
2014-06-21o3: split load & store queue full cases in renameBinh Pham
Check for free entries in Load Queue and Store Queue separately to avoid cases when load cannot be renamed due to full Store Queue and vice versa. This work was done while Binh was an intern at AMD Research.
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: Useful getters for ActivityRecorderAndrew Bardsley
Add some useful getters to ActivityRecorder
2014-05-09cpu: Add flag name printing to StaticInstAndrew Bardsley
This patch adds a the member function StaticInst::printFlags to allow all of an instruction's flags to be printed without using the individual is... member functions or resorting to exposing the 'flags' vector It also replaces the enum definition StaticInst::Flags with a Python-generated enumeration and adds to the enum generation mechanism in src/python/m5/params.py to allow Enums to be placed in namespaces other than Enums or, alternatively, in wrapper structs allowing them to be inherited by other classes (so populating that class's name-space with the enumeration element names).
2014-05-09cpu: Timebuf const accessorsAndrew Bardsley
Add const accessors for timebuf elements.
2014-05-09arch, arm: Preserve TLB bootUncacheability when switching CPUsGeoffrey Blake
The ARM TLBs have a bootUncacheability flag used to make some loads and stores become uncacheable when booting in FS mode. Later the flag is cleared to let those loads and stores operate as normal. When doing a takeOverFrom(), this flag's state is not preserved and is momentarily reset until the CPSR is touched. On single core runs this is a non-issue. On multi-core runs this can lead to crashes on the O3 CPU model from the following series of events: 1) takeOverFrom executed to switch from Atomic -> O3 2) All bootUncacheability flags are reset to true 3) Core2 tries to execute a load covered by bootUncacheability, it is flagged as uncacheable 4) Core2's load needs to replay due to a pipeline flush 3) Core1 core does an action on CPSR 4) The handling code for CPSR then checks all other cores to determine if bootUncacheability can be set to false 5) Asynchronously set bootUncacheability on all cores to false 6) Core2 replays load previously set as uncacheable and notices it is now flagged as cacheable, leads to a panic. This patch implements takeOverFrom() functionality for the ARM TLBs to preserve flag values when switching from atomic -> detailed.
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.
2014-04-23cpu: Fix setTranslateLatency() bug for squashed instructionsMitchell Hayenga
setTranslateLatency could sometimes improperly access a deleted request packet after an instruction was squashed.