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path: root/src/cpu/simple/timing.cc
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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.
2014-05-13mem: 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.
2014-01-24cpu: 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.
2014-01-24mem: 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.
2013-08-19cpu: Accurately count idle cycles for simple cpuLena Olson
Added a couple missing updates to the notIdleFraction stat. Without these, it sometimes gives a (not) idle fraction that is greater than 1 or less than 0.
2013-08-19cpu: Fix timing CPU drain checkAndreas Hansson
This patch modifies the SimpleTimingCPU drain check to also consider the fetch event. Previously, there was an assumption that there is never a fetch event scheduled if the CPU is not executing microcode. However, when a context is activated, a fetch even is scheduled, and microPC() is zero.
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.
2013-04-22sim: 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.
2013-02-15sim: Add a system-global option to bypass cachesAndreas Sandberg
Virtualized CPUs and the fastmem mode of the atomic CPU require direct access to physical memory. We currently require caches to be disabled when using them to prevent chaos. This is not ideal when switching between hardware virutalized CPUs and other CPU models as it would require a configuration change on each switch. This changeset introduces a new version of the atomic memory mode, 'atomic_noncaching', where memory accesses are inserted into the memory system as atomic accesses, but bypass caches. To make memory mode tests cleaner, the following methods are added to the System class: * isAtomicMode() -- True if the memory mode is 'atomic' or 'direct'. * isTimingMode() -- True if the memory mode is 'timing'. * bypassCaches() -- True if caches should be bypassed. The old getMemoryMode() and setMemoryMode() methods should never be used from the C++ world anymore.
2013-02-15cpu: Refactor memory system checksAndreas Sandberg
CPUs need to test that the memory system is in the right mode in two places, when the CPU is initialized (unless it's switched out) and on a drainResume(). This led to some code duplication in the CPU models. This changeset introduces the verifyMemoryMode() method which is called by BaseCPU::init() if the CPU isn't switched out. The individual CPU models are responsible for calling this method when resuming from a drain as this code is CPU model specific.
2013-01-07cpu: Unify the serialization code for all of the CPU modelsAndreas Sandberg
Cleanup the serialization code for the simple CPUs and the O3 CPU. The CPU-specific code has been replaced with a (un)serializeThread that serializes the thread state / context of a specific thread. Assuming that the thread state class uses the CPU-specific thread state uses the base thread state serialization code, this allows us to restore a checkpoint with any of the CPU models.
2013-01-07cpu: Make sure that a drained timing CPU isn't executing ucodeAndreas Sandberg
Currently, the timing CPU can be in the middle of a microcode sequence or multicycle (stayAtPC is true) instruction when it is drained. This leads to two problems: * When switching to a hardware virtualized CPU, we obviously can't execute gem5 microcode. * If stayAtPC is true we might execute half of an instruction twice when restoring a checkpoint or switching CPUs, which leads to an incorrect execution. After applying this patch, the CPU will be on a proper instruction boundary, which means that it is safe to switch to any CPU model (including hardware virtualized ones). This changeset also fixes a bug where the timing CPU sometimes switches out with while stayAtPC is true, which corrupts the target state after a CPU switch or checkpoint. Note: This changeset removes the so_state variable from checkpoints since the drain state isn't used anymore.
2013-01-07cpu: Rename defer_registration->switched_outAndreas Sandberg
The defer_registration parameter is used to prevent a CPU from initializing at startup, leaving it in the "switched out" mode. The name of this parameter (and the help string) is confusing. This patch renames it to switched_out, which should be more descriptive.
2013-01-07cpu: Correctly call parent on switchOut() and takeOverFrom()Andreas Sandberg
This patch cleans up the CPU switching functionality by making sure that CPU models consistently call the parent on switchOut() and takeOverFrom(). This has the following implications that might alter current functionality: * The call to BaseCPU::switchout() in the O3 CPU is moved from signalDrained() (!) to switchOut(). * A call to BaseSimpleCPU::switchOut() is introduced in the simple CPUs.
2013-01-07cpu: Check that the memory system is in the correct modeAndreas Sandberg
This patch adds checks to all CPU models to make sure that the memory system is in the correct mode at startup and when resuming after a drain. Previously, we only checked that the memory system was in the right mode when resuming. This is inadequate since this is a configuration error that should be detected at startup as well as when resuming. Additionally, since the check was done using an assert, it wasn't performed when NDEBUG was set (e.g., the fast target).
2012-11-02sim: Move the draining interface into a separate base classAndreas Sandberg
This patch moves the draining interface from SimObject to a separate class that can be used by any object needing draining. However, objects not visible to the Python code (i.e., objects not deriving from SimObject) still depend on their parents informing them when to drain. This patch also gets rid of the CountedDrainEvent (which isn't really an event) and replaces it with a DrainManager.
2012-08-28Clock: Add a Cycles wrapper class and use where applicableAndreas Hansson
This patch addresses the comments and feedback on the preceding patch that reworks the clocks and now more clearly shows where cycles (relative cycle counts) are used to express time. Instead of bumping the existing patch I chose to make this a separate patch, merely to try and focus the discussion around a smaller set of changes. The two patches will be pushed together though. This changes done as part of this patch are mostly following directly from the introduction of the wrapper class, and change enough code to make things compile and run again. There are definitely more places where int/uint/Tick is still used to represent cycles, and it will take some time to chase them all down. Similarly, a lot of parameters should be changed from Param.Tick and Param.Unsigned to Param.Cycles. In addition, the use of curTick is questionable as there should not be an absolute cycle. Potential solutions can be built on top of this patch. There is a similar situation in the o3 CPU where lastRunningCycle is currently counting in Cycles, and is still an absolute time. More discussion to be had in other words. An additional change that would be appropriate in the future is to perform a similar wrapping of Tick and probably also introduce a Ticks class along with suitable operators for all these classes.
2012-08-28Clock: Rework clocks to avoid tick-to-cycle transformationsAndreas Hansson
This patch introduces the notion of a clock update function that aims to avoid costly divisions when turning the current tick into a cycle. Each clocked object advances a private (hidden) cycle member and a tick member and uses these to implement functions for getting the tick of the next cycle, or the tick of a cycle some time in the future. In the different modules using the clocks, changes are made to avoid counting in ticks only to later translate to cycles. There are a few oddities in how the O3 and inorder CPU count idle cycles, as seen by a few locations where a cycle is subtracted in the calculation. This is done such that the regression does not change any stats, but should be revisited in a future patch. Another, much needed, change that is not done as part of this patch is to introduce a new typedef uint64_t Cycle to be able to at least hint at the unit of the variables counting Ticks vs Cycles. This will be done as a follow-up patch. As an additional follow up, the thread context still uses ticks for the book keeping of last activate and last suspend and this should probably also be changed into cycles as well.
2012-08-22Packet: Remove NACKs from packet and its use in endpointsAndreas Hansson
This patch removes the NACK frrom the packet as there is no longer any module in the system that issues them (the bridge was the only one and the previous patch removes that). The handling of NACKs was mostly avoided throughout the code base, by using e.g. panic or assert false, but in a few locations the NACKs were actually dealt with (although NACKs never occured in any of the regressions). Most notably, the DMA port will now never receive a NACK and the backoff time is thus never changed. As a consequence, the entire backoff mechanism (similar to a PCI bus) is now removed and the DMA port entirely relies on the bus performing the arbitration and issuing a retry when appropriate. This is more in line with e.g. PCIe. Surprisingly, this patch has no impact on any of the regressions. As mentioned in the patch that removes the NACK from the bridge, a follow-up patch should change the request and response buffer size for at least one regression to also verify that the system behaves as expected when the bridge fills up.
2012-08-15O3,ARM: fix some problems with drain/switchout functionality and add Drain ↵Anthony Gutierrez
DPRINTFs This patch fixes some problems with the drain/switchout functionality for the O3 cpu and for the ARM ISA and adds some useful debug print statements. This is an incremental fix as there are still a few bugs/mem leaks with the switchout code. Particularly when switching from an O3CPU to a TimingSimpleCPU. However, when switching from O3 to O3 cores with the ARM ISA I haven't encountered any more assertion failures; now the kernel will typically panic inside of simulation.
2012-06-05cpu: Don't init simple and inorder CPUs if they are defered.Anthony Gutierrez
initCPU() will be called to initialize switched out CPUs for the simple and inorder CPU models. this patch prevents those CPUs from being initialized because they should get their state from the active CPU when it is switched out.
2012-05-01MEM: Separate requests and responses for timing accessesAndreas Hansson
This patch moves send/recvTiming and send/recvTimingSnoop from the Port base class to the MasterPort and SlavePort, and also splits them into separate member functions for requests and responses: send/recvTimingReq, send/recvTimingResp, and send/recvTimingSnoopReq, send/recvTimingSnoopResp. A master port sends requests and receives responses, and also receives snoop requests and sends snoop responses. A slave port has the reciprocal behaviour as it receives requests and sends responses, and sends snoop requests and receives snoop responses. For all MemObjects that have only master ports or slave ports (but not both), e.g. a CPU, or a PIO device, this patch merely adds more clarity to what kind of access is taking place. For example, a CPU port used to call sendTiming, and will now call sendTimingReq. Similarly, a response previously came back through recvTiming, which is now recvTimingResp. For the modules that have both master and slave ports, e.g. the bus, the behaviour was previously relying on branches based on pkt->isRequest(), and this is now replaced with a direct call to the apprioriate member function depending on the type of access. Please note that send/recvRetry is still shared by all the timing accessors and remains in the Port base class for now (to maintain the current bus functionality and avoid changing the statistics of all regressions). The packet queue is split into a MasterPort and SlavePort version to facilitate the use of the new timing accessors. All uses of the PacketQueue are updated accordingly. With this patch, the type of packet (request or response) is now well defined for each type of access, and asserts on pkt->isRequest() and pkt->isResponse() are now moved to the appropriate send member functions. It is also worth noting that sendTimingSnoopReq no longer returns a boolean, as the semantics do not alow snoop requests to be rejected or stalled. All these assumptions are now excplicitly part of the port interface itself.
2012-04-14MEM: Remove the Broadcast destination from the packetAndreas Hansson
This patch simplifies the packet by removing the broadcast flag and instead more firmly relying on (and enforcing) the semantics of transactions in the classic memory system, i.e. request packets are routed from a master to a slave based on the address, and when they are created they have neither a valid source, nor destination. On their way to the slave, the request packet is updated with a source field for all modules that multiplex packets from multiple master (e.g. a bus). When a request packet is turned into a response packet (at the final slave), it moves the potentially populated source field to the destination field, and the response packet is routed through any multiplexing components back to the master based on the destination field. Modules that connect multiplexing components, such as caches and bridges store any existing source and destination field in the sender state as a stack (just as before). The packet constructor is simplified in that there is no longer a need to pass the Packet::Broadcast as the destination (this was always the case for the classic memory system). In the case of Ruby, rather than using the parameter to the constructor we now rely on setDest, as there is already another three-argument constructor in the packet class. In many places where the packet information was printed as part of DPRINTFs, request packets would be printed with a numeric "dest" that would always be -1 (Broadcast) and that field is now removed from the printing.
2012-04-14MEM: Separate snoops and normal memory requests/responsesAndreas Hansson
This patch introduces port access methods that separates snoop request/responses from normal memory request/responses. The differentiation is made for functional, atomic and timing accesses and builds on the introduction of master and slave ports. Before the introduction of this patch, the packets belonging to the different phases of the protocol (request -> [forwarded snoop request -> snoop response]* -> response) all use the same port access functions, even though the snoop packets flow in the opposite direction to the normal packet. That is, a coherent master sends normal request and receives responses, but receives snoop requests and sends snoop responses (vice versa for the slave). These two distinct phases now use different access functions, as described below. Starting with the functional access, a master sends a request to a slave through sendFunctional, and the request packet is turned into a response before the call returns. In a system without cache coherence, this is all that is needed from the functional interface. For the cache-coherent scenario, a slave also sends snoop requests to coherent masters through sendFunctionalSnoop, with responses returned within the same packet pointer. This is currently used by the bus and caches, and the LSQ of the O3 CPU. The send/recvFunctional and send/recvFunctionalSnoop are moved from the Port super class to the appropriate subclass. Atomic accesses follow the same flow as functional accesses, with request being sent from master to slave through sendAtomic. In the case of cache-coherent ports, a slave can send snoop requests to a master through sendAtomicSnoop. Just as for the functional access methods, the atomic send and receive member functions are moved to the appropriate subclasses. The timing access methods are different from the functional and atomic in that requests and responses are separated in time and send/recvTiming are used for both directions. Hence, a master uses sendTiming to send a request to a slave, and a slave uses sendTiming to send a response back to a master, at a later point in time. Snoop requests and responses travel in the opposite direction, similar to what happens in functional and atomic accesses. With the introduction of this patch, it is possible to determine the direction of packets in the bus, and no longer necessary to look for both a master and a slave port with the requested port id. In contrast to the normal recvFunctional, recvAtomic and recvTiming that are pure virtual functions, the recvFunctionalSnoop, recvAtomicSnoop and recvTimingSnoop have a default implementation that calls panic. This is to allow non-coherent master and slave ports to not implement these functions.
2012-03-30CPU: Unify initMemProxies across CPUs and simulation modesAndreas Hansson
This patch unifies where initMemProxies is called, in the init() method of each BaseCPU subclass, before TheISA::initCPU is called. Moreover, it also ensures that initMemProxies is called in both full-system and syscall-emulation mode, thus unifying also across the modes. An additional check is added in the ThreadState to ensure that initMemProxies is only called once.
2012-02-24CPU: Round-two unifying instr/data CPU ports across modelsAndreas Hansson
This patch continues the unification of how the different CPU models create and share their instruction and data ports. Most importantly, it forces every CPU to have an instruction and a data port, and gives these ports explicit getters in the BaseCPU (getDataPort and getInstPort). The patch helps in simplifying the code, make assumptions more explicit, andfurther ease future patches related to the CPU ports. The biggest changes are in the in-order model (that was not modified in the previous unification patch), which now moves the ports from the CacheUnit to the CPU. It also distinguishes the instruction fetch and load-store unit from the rest of the resources, and avoids the use of indices and casting in favour of keeping track of these two units explicitly (since they are always there anyways). The atomic, timing and O3 model simply return references to their already existing ports.
2012-02-12mem: Add a master ID to each request object.Ali Saidi
This change adds a master id to each request object which can be used identify every device in the system that is capable of issuing a request. This is part of the way to removing the numCpus+1 stats in the cache and replacing them with the master ids. This is one of a series of changes that make way for the stats output to be changed to python.
2012-01-31Merge with head, hopefully the last time for this batch.Gabe Black
2012-01-31clang: Enable compiling gem5 using clang 2.9 and 3.0Koan-Sin Tan
This patch adds the necessary flags to the SConstruct and SConscript files for compiling using clang 2.9 and later (on Ubuntu et al and OSX XCode 4.2), and also cleans up a bunch of compiler warnings found by clang. Most of the warnings are related to hidden virtual functions, comparisons with unsigneds >= 0, and if-statements with empty bodies. A number of mismatches between struct and class are also fixed. clang 2.8 is not working as it has problems with class names that occur in multiple namespaces (e.g. Statistics in kernel_stats.hh). clang has a bug (http://llvm.org/bugs/show_bug.cgi?id=7247) which causes confusion between the container std::set and the function Packet::set, and this is currently addressed by not including the entire namespace std, but rather selecting e.g. "using std::vector" in the appropriate places.
2012-01-28Merge with the main repo.Gabe Black
--HG-- rename : src/mem/vport.hh => src/mem/fs_translating_port_proxy.hh rename : src/mem/translating_port.cc => src/mem/se_translating_port_proxy.cc rename : src/mem/translating_port.hh => src/mem/se_translating_port_proxy.hh
2012-01-17MEM: Simplify ports by removing EventManagerAndreas Hansson
This patch removes the inheritance of EventManager from the ports and moves all responsibility for event queues to the owner. Eventually the event manager should be the interface block, which could either be the structural owner or a subblock like a LSQ in the O3 CPU for example.
2012-01-17CPU: Moving towards a more general port across CPU modelsAndreas Hansson
This patch performs minimal changes to move the instruction and data ports from specialised subclasses to the base CPU (to the largest degree possible). Ultimately it servers to make the CPU(s) have a well-defined interface to the memory sub-system.
2012-01-17MEM: Add port proxies instead of non-structural portsAndreas Hansson
Port proxies are used to replace non-structural ports, and thus enable all ports in the system to correspond to a structural entity. This has the advantage of accessing memory through the normal memory subsystem and thus allowing any constellation of distributed memories, address maps, etc. Most accesses are done through the "system port" that is used for loading binaries, debugging etc. For the entities that belong to the CPU, e.g. threads and thread contexts, they wrap the CPU data port in a port proxy. The following replacements are made: FunctionalPort > PortProxy TranslatingPort > SETranslatingPortProxy VirtualPort > FSTranslatingPortProxy --HG-- rename : src/mem/vport.cc => src/mem/fs_translating_port_proxy.cc rename : src/mem/vport.hh => src/mem/fs_translating_port_proxy.hh rename : src/mem/translating_port.cc => src/mem/se_translating_port_proxy.cc rename : src/mem/translating_port.hh => src/mem/se_translating_port_proxy.hh
2011-11-18SE/FS: Get rid of FULL_SYSTEM in the CPU directory.Gabe Black
2011-11-01SE/FS: Expose the same methods on the CPUs in SE and FS modes.Gabe Black
2011-08-07Translation: Use a pointer type as the template argument.Gabe Black
This allows regular pointers and reference counted pointers without having to use any shim structures or other tricks.
2011-07-02ExecContext: Rename the readBytes/writeBytes functions to readMem and writeMem.Gabe Black
readBytes and writeBytes had the word "bytes" in their names because they accessed blobs of bytes. This distinguished them from the read and write functions which handled higher level data types. Because those functions don't exist any more, this change renames readBytes and writeBytes to more general names, readMem and writeMem, which reflect the fact that they are how you read and write memory. This also makes their names more consistent with the register reading/writing functions, although those are still read and set for some reason.
2011-07-02ExecContext: Get rid of the now unused read/write templated functions.Gabe Black
2011-05-04CPU: Add some useful debug message to the timing simple cpu.Ali Saidi
2011-05-04CPU: Fix a case where timing simple cpu faults can nest.Ali Saidi
If we fault, change the state to faulting so that we don't fault again in the same cycle.
2011-04-15trace: reimplement the DTRACE function so it doesn't use a vectorNathan Binkert
At the same time, rename the trace flags to debug flags since they have broader usage than simply tracing. This means that --trace-flags is now --debug-flags and --trace-help is now --debug-help
2011-04-15includes: sort all includesNathan Binkert
2011-03-17ARM: Detect and skip udelay() functions in linux kernel.Ali Saidi
This change speeds up booting, especially in MP cases, by not executing udelay() on the core but instead skipping ahead tha amount of time that is being delayed.
2011-03-01Spelling: Fix the a spelling error by changing mmaped to mmapped.Gabe Black
There may not be a formally correct spelling for the past tense of mmap, but mmapped is the spelling Google doesn't try to autocorrect. This makes sense because it mirrors the past tense of map->mapped and not the past tense of cape->caped. --HG-- rename : src/arch/alpha/mmaped_ipr.hh => src/arch/alpha/mmapped_ipr.hh rename : src/arch/arm/mmaped_ipr.hh => src/arch/arm/mmapped_ipr.hh rename : src/arch/mips/mmaped_ipr.hh => src/arch/mips/mmapped_ipr.hh rename : src/arch/power/mmaped_ipr.hh => src/arch/power/mmapped_ipr.hh rename : src/arch/sparc/mmaped_ipr.hh => src/arch/sparc/mmapped_ipr.hh rename : src/arch/x86/mmaped_ipr.hh => src/arch/x86/mmapped_ipr.hh
2011-02-11SimpleCPU: Fix a case where a DTLB fault redirects fetch and an I-side walk ↵Ali Saidi
occurs. This change fixes an issue where a DTLB fault occurs and redirects fetch to handle the fault and the ITLB requires a walk which delays translation. In this case the status of the cpu isn't updated appropriately, and an additional instruction fetch occurs. Eventually this hits an assert as multiple instruction fetches are occuring in the system and when the second one returns the processor is in the wrong state. Some asserts below are removed because it was always true (typo) and the state after the initiateAcc() the processor could be in any valid state when a d-side fault occurs.
2011-02-06TimingSimpleCPU: split data sender state fixJoel Hestness
In sendSplitData, keep a pointer to the senderState that may be updated after the call to handle*Packet. This way, if the receiver updates the packet senderState, it can still be accessed in sendSplitData.
2011-02-06mcpat: Adds McPAT performance countersJoel Hestness
Updated patches from Rick Strong's set that modify performance counters for McPAT
2011-01-07Replace curTick global variable with accessor functions.Steve Reinhardt
This step makes it easy to replace the accessor functions (which still access a global variable) with ones that access per-thread curTick values.